ORTHOPEDIC MCQS ONLINE 013 PEDIATRIC 

2013 Pediatric Orthopaedic Self-Assessment Examination by Dr.Dhahirortho

 

 

1

 

 

 

Question 1-Figure 1 is the radiograph of a child who has pain in his left thigh. Extensive pigmentation with a jagged border is seen on the left trunk. This child is at increased risk for

 

1. patellar instability and nail abnormalities.

2. involvement of other bones and precocious puberty.

3. cardiac abnormalities and hearing loss.

4. syndactyly and fibular hypoplasia.

 

DISCUSSION-The radiograph shows coxa vara with a lucency in the femoral neck, typical of the ”ground glass“appearance of fibrous dysplasia.

Hyperpigmentantion with a ”Coast of Maine“ border is indicative of McCune-Albright syndrome, which consists of polyostotic fibrous dyplasia and endocrine disturbances,especially precocious puberty. Nail deformity, patellar instability, cardiac abnormalities, hearing loss,syndactyly, and fibula abnormalities are not associated with this syndrome. PREFERRED RESPONSE: 2

 

 

 

Question 2-What gene is implicated in spinal muscular atrophy?

1. Survival motor neuron I (SMN-I)

2. Peripheral myelin protein 22 (PMP22)

3. Dystrophin

4. Androgen receptor

 

DISCUSSION-Deletions in the SMN-I gene are found in 95% to 98% of patients with spinal muscular atrophy. Genetic testing is typically part of the diagnostic workup for spinal muscular atrophy. A positive test result is diagnostic, and, in most cases, eliminates the need for muscle biopsy. The other choices are not associated with spinal muscular atrophy. Defects in PMP22 are the cause of 70% to 80% of cases of Charcot-Marie-Tooth disease. Mutations in the dystrophin gene cause Duchenne muscular dystrophy, and mutations in the androgen receptor cause spinobulbar muscular atrophy (Kennedy’s disease).

PREFERRED RESPONSE: 1

 

 

 

Question 3-Video 3 shows the physical examination of the right hip of a 14-day-old full-term female infant. There is no history of breech presentation, she was born vaginally, and is the second child born to her mother. She is otherwise healthy and has been eating and gaining weight appropriately. What is the most appropriate course of action at this time?

 

1. Observation, with a repeat clinical examination in 2 weeks

2. Application of a hip abduction device and early follow-up to confirm reduction

3. Arthrogram and closed reduction of the right hip under general anesthetic, followed by spica casting

4. Open reduction of the right hip with a capsulorrhaphy

 

DISCUSSION-The video shows an unstable right hip in a female infant. The visual ”clunk“ of the positive Barlow and Ortolani tests is readily evident. Initial treatment in a young infant consists of application of an abduction device to achieve and maintain hip location. Confirmation of successful hip location is usually performed by ultrasound examination. In the United States, the Pavlik harness remains the most commonly used hip abduction device, although others, such as hip abduction braces and the Frejka pillow, are available and have been shown to have similar success.

Observation is not necessary when the examination shows clear instability. Arthrogram, closed manipulation, and spica casting are reserved for an older age group (those between 6 and 18 months of age). Open reduction is appropriate if the hip remains dislocated after 18 months of age.

PREFERRED RESPONSE: 2

 

 

 

Question 4 -Figures 4a and 4b are the radiographs of a 7-year-old girl who fell and sustained an injury to her left elbow in a foreign country 2 years ago. She was treated by a local ”healer“ with arm massage. Her pain and swelling improved, but her mother noticed an abnormal appearance of the elbow that clinically manifested as cubitus valgus. The child denied significant pain or functional limitations. Her neurologic and vascular examination findings are normal. She denies fever, weight loss, or systemic illness. Her elbow is not tender, there is no instability, and her range of motion reveals full flexion, extension, pronation, and supination of the elbow. What is the most appropriate course of action?

 

1. Observation

2. Administration of intravenous antibiotics

3. Operative repair and bone grafting of the nonunited fragment

4. Distal humerus osteotomy to correct cubitus valgus

 

DISCUSSION-The patient and her parents should be counseled that although progressive cubitus valgus, pain, instability,and tardy ulnar nerve palsy can occur, their incidence in this setting is unknown, and, as long as the girl remains asymptomatic, observation is appropriate. The radiographs reveal a chronic nonunion of a lateral humeral condyle fracture.

Although the appearance could be confused

with osteomyelitis, the patient has a history of trauma and no clinical symptoms of infection. Fixation of the distal fragment has been recommended to relieve pain and instability. Distal humerus osteotomy has been recommended to correct cubitus valgus and to treat tardy ulnar nerve palsy.

 

 

PREFERRED RESPONSE: 1

 

Question 5-Figure 5 is the anteroposterior radiograph of a 7-year-old girl with a congenital limb difference. This type of limb difference commonly is associated with

 

1. insufficient medial collateral ligament of the knee (MCL).

2. insufficient extensor mechanism.

3. absent lateral rays of the foot.

4. cleft hands.

 

DISCUSSION -Fibular hemimelia is associated with missing or absent lateral rays/toes, partial or complete absence of the fibula, and anterior cruciate ligament insufficiency. Tibial hemimelia is associated with insufficient extensor mechanism, clubfoot deformity, and, in some cases, cleft hands. MCL is not usually involved in this disorder. PREFERRED RESPONSE: 3

 

Question 6-Figures 6a through 6d are the CT scans of a 5-year-old girl who fell out of bed 4 weeks ago. She had been treated for a nondisplaced clavicle fracture by her pediatrician and was referred for evaluation of acute torticollis that was noticed after her fall. On examination, she had a fixed torticollis and resisted all attempts at manipulation. The family denied a prior history of torticollis. What is the most appropriate next step in her treatment?

 

 

1. Cervical traction

2. Sternocleidomastoid release

3. Use of a soft cervical collar

4. Posterior cervical fusion

 

 

DISCUSSION -Cervical traction, usually initiated with a Halter device, is the most appropriate initial

treatment. Halo traction may eventually be required, especially in long-standing cases, because of the inability of a child’s skin to handle the traction weight and difficulty maintaining Halter traction at increased weights. The CT scans show an atlantoaxial rotatory fixation of C1 on C2, which can happen after acute trauma. Given the long-standing nature of the problem, a soft cervical collar will be of no benefit but may be useful in acute cases associated with upper respiratory tract infections.

Sternocleidomastoid release is used in cases of congenital muscular torticollis, a condition ruled out by this child’s history. Posterior cervical fusion is reserved for children who have failed nonsurgical treatment such as traction. PREFERRED RESPONSE: 1

 

CLINICAL SITUATION FOR QUESTIONS 7 AND 8

 

 

Figures 7a and 7b are the MRI and CT scans of a 12-year-old boy who has had 1 week of low-back pain, a low-grade fever, and an elevated erythrocyte sedimentation rate and white blood cell count. Figure 7a Figure 7b

Question 7-What is the most likely diagnosis?

 

1. Osteomyelitis of the spine

2. Aneurysmal bone cyst

3. Herniated nucleus pulposus

4. Hemangioma

 

PREFERRED RESPONSE: 1

Question 8-What is the most appropriate next treatment step?

 

1. Open biopsy

2. Extension casting

3. CT scan of the chest

4. Blood culture and image-guided needle biopsy or aspiration

 

PREFERRED RESPONSE: 4

 

DISCUSSION FOR QUESTIONS 7 AND 8

Based on the patient’s signs and symptoms, the most likely diagnosis is osteomyelitis of the spine. The imaging studies do not reveal a herniated disk, which would be unusual in someone of this age. Aneurysmal bone cysts would involve the posterior elements with a more expansive lesion of bone, whereas this lesion involves primarily the body and anterior column. Hemangioma would likely not be present with systemic signs or symptoms and has a more characteristic coarse trabecular pattern on radiographs and scans. Given the likelihood that this patient has osteomyelitis of the spine, blood cultures may yield an organism about 50% of the time. If cultures are negative, an image-guided biopsy is warranted. A diagnosis needs to be established before treatment such as extension casting or bracing is rendered. Open biopsy may still be needed if needle biopsy is not diagnostic, but this is not the first treatment option. A chest CT scan is not appropriate as a first step when a tumor is presumed and a diagnosis has not been established.

 

 

 

Question 9-Figures 9a and 9b are the anteroposterior and lateral tibia/fibula radiographs of a 6-month-old infant who was evaluated for a bowed leg. In addition to brace treatment, initial treatment should include

 

1. cast immobilization in a long-leg cast for 4 to 6 weeks to heal the fracture.

2. open reduction and fixation because of the amount of deformity.

3. skeletal survey and referral to social services for evaluation of abuse.

4. referral to genetics to evaluate for a systemic disease.

 

DISCUSSION-The radiographs show a severe pseudarthrosis tibia/fibula that has fractured. This is highly associated with neurofibromatosis type I, which needs to be evaluated with a genetics workup before discussing treatment.

Cast immobilization is not needed if the child is not walking and not in pain. Surgical management should proceed only after the

workup is complete. This is a congenital condition, not a fracture, so workup for abuse is not indicated. PREFERRED RESPONSE: 4

 

 

 

Question 10-Figures 10a and 10b are the sagittal and coronal MRI scans of a 5-year-old boy who noticed “clicking” in his right knee. His family denied any trauma, but admitted that the child was active and fell frequently.Birth and developmental history were unremarkable, and specifically negative for other musculoskeletal conditions. On physical examination, there was no warmth, tenderness, or erythema, or effusion. The child had an audible and palpable clunk when the knee was taken from a position of extreme flexion to full extension. There was no anterior, posterior, medial, or lateral instability on examination or medial or lateral joint line tenderness. The child had not been systemically ill. Radiographs were unrevealing.What is the most likely diagnosis?

 

1. Discoid lateral meniscus

2. Congenital absence of the anterior cruciate ligament

3. Torn medial meniscus

4. Osteomyelitis of the distal femur

 

DISCUSSION A discoid lateral meniscus is probably the most common cause of a symptomatic clicking or clunking in the knee in a young child. This is a congenital problem that can become symptomatic as soon as a child ambulates, or the condition may remain asymptomatic for several years. The meniscus develops from a cartilaginous anlage and at no point in its development is it discoid. The MRI scans reveal a band of meniscal tissue filling the joint’s lateral compartment on both sagittal and coronal images. A

medial meniscal tear is usually accompanied by a history of injury and an effusion, which are not present in this child. There is also no joint line tenderness, which makes this diagnosis less likely. Congenital absence of the anterior cruciate ligament may be found in children born with congenital knee hyperextension, which is ruled out in this case by normal history and examination findings.

Children with osteomyelitis are often systemically ill. On examination, they may have warmth and tenderness. MRI scans will often show an area of increased signal on T1-weighted images.

 

PREFERRED RESPONSE: 1

 

 

 

Question 11-Figure 11 is the radiograph of a 9-year-old African-American boy with left-sided groin and knee pain. His body mass index is 42, and he has had symptoms for 10 days. What is the recommended treatment?

 

1. Physical therapy and a return visit in 6 weeks

2. Crutches and toe-touch weight bearing for 6 weeks

3. Open hip dislocation and a modified Dunn procedure

4. Percutaneous screw fixation of both hips

 

DISCUSSION-This patient is young, obese, and African American. His risk of slip on the right is at least 50%. The radiograph shows a grade 1 slip on the left and an open triradiate cartilage. Recommendations for this patient should include fixation of both hips because risk for problems after a slip of the opposite side is higher than risk for prophylactic fixation. Physical therapy may make the condition worse.

Toetouch weight bearing would only delay needed treatment. The left hip should be treated and the family may elect to only treat the left hip, but recommendations should be given to treat

both hips. Open-hip dislocation is not indicated in this mild slipped capital femoral epiphysis. PREFERRED RESPONSE: 4

 

 

 

Question 12-Figure 12 is the radiograph of a 3-year-old who has deformity of the first ray of the right foot. What is the most appropriate recommendation at this time?

 

1. Observation

2. Excision of the abnormal structure

3. Lengthening of the metatarsal with external fixation

4. Ray resection

 

DISCUSSION -The oblique radiograph shows a well-formed congenital longitudinal epiphyseal bracket. Excision of the bracket leads to decreased deformity and improves the potential for longitudinal growth. Observation alone will lead to the relative shortening of the first metatarsal and medial deviation of the hallux. Metatarsal lengthening can be considered if resection does not lead to sufficient growth. Ray resection is not necessary. PREFERRED RESPONSE: 2

 

 

 

Question 13Figure 13 is the photograph of 18-month-old triplets with a lower-limb condition. What is the best initial treatment?

 

1. Vitamin D supplementation and serum level monitoring

2. Mechanical axis alignment measurements on serial standing knee radiographs

3. Genetic testing and counseling for short-stature syndrome

4. Observation and clinical follow-up.

 

DISCUSSION --These triplets exhibit genu varum and internal tibial torsion that can be part of normal development. Fetal

packing is the likely major contributing cause for these triplets, however. Observation and follow-up will be sufficient. Bowing and torsion can be clinical features of vitamin D deficiency, Blount disease, and short-stature syndromes, but these are not the most likely diagnoses. Radiographic diagnosis of Blount disease may not be accurate at this age.

PREFERRED RESPONSE: 4

 

Question 14-Figures 14a through 14d are the radiographs and sagittal T1- and T2-weighted MRI scans of an otherwise healthy 10-year-old girl who has experienced 3 weeks of worsening pain with weight bearing and is now refusing to bear weight to either of her lower extremities. She denies any history of injury or trauma.She has not had any fevers or recent illnesses. She denies any numbness or parasthesias. She has had no bowel or bladder incontinence. In the emergency department she is afebrile and tender to palpation over the midlumbar spine. She has pain with hyperextension and flexion of her back. Her white blood cell count is 11.4 (reference range, 4.5-11.0 x109/L), erythrocyte sedimentation rate is 40 mm/h (reference range, 0-20 mm/h), and C-reactive protein is 2.6 mg/L (reference range, 0.08-3.1 mg/L). What is the most appropriate course of action at this time?

 

 

1. Admission and traction

2. Open surgical debridement of the lesion

3. Perform an open biopsy of the lesion

4. Nonsurgical treatment with antibiotics and immobilization

 

DISCUSSION -Childhood diskitis represents one end of a continuum of spinal infections, from diskitis to vertebral osteomyelitis with soft-tissue abscess. Diskitis is now generally accepted as a bacterial infection involving the disk space and adjacent vertebral end plates. Optimal treatment includes the use of antibiotics. Empiric coverage is directed against Staphylococcus aureus because it has been the most common organism isolated from culture-positive biopsy specimens. Open biopsy is not necessary for patients who exhibit all of these clinical characteristics, but it is indicated for those whose symptoms do not resolve rapidly with treatment or who have atypical presentation.

PREFERRED RESPONSE: 4

 

 

 

Question 15-Figure 15 is the photograph of a 3-year-old girl. She has intoeing (30-degree internal foot progression angle) and tripping when running fast. Prone examination reveals a neutral thigh foot angle and hips that rotate internally 85 degrees and externally 15 degrees. She has no pain; the remainder of her examination and history is unremarkable. What is the most appropriate treatment?

 

1. Surgical derotation osteotomy of the femurs

2. Shoe inserts

3. A nighttime external rotation brace and physical therapy

4. Observation

 

DISCUSSION -This patient has femoral anteversion, which peaks at around this age. An awkward intoeing gait and W sitting are common complaints, but pain is

rare. Observation is recommended. Special shoes, therapy,and derotating braces have never been shown to improve rates of remodeling, which approach 99% by age8 to 10.

PREFERRED RESPONSE: 4

 

Question 16-A 1-week-old infant was placed in a Pavlik harness for an Ortolani-positive hip. She was seen on a weekly basis and her hip remained dislocated 3 weeks later. What is the most appropriate treatment?

 

1. Continue the Pavlik harness

2. Switch to an abduction orthosis

3. Plan for closed reduction of the hip

4. Schedule for open reduction

 

DISCUSSION-Two series have documented successful hip reduction with rigid abduction orthoses after the failure of Pavlik harness treatment. If a dislocated hip has not stabilized with 3 weeks of Pavlik treatment,prolonging treatment can lead to “Pavlik disease,” or erosion of the posterior margin of the acetabulum.Closed or open reduction should be deferred in favor of a trial of abduction bracing. PREFERRED RESPONSE: 2

 

Question 17-A 15-year-old boy fell from a tree and sustained the injury shown in Figures 17a and 17b. He was treated with closed manipulation and splinting. His radiographs after manipulation are shown in Figures 17c and 17d. His follow-up radiographs, taken 1 week later, are shown in Figures 17e and 17f. At this current follow-up visit, which treatment recommendation is most appropriate?

 

 

1. Acceptance of the current deformity, with the expectation that his bone will remodel

2. Remanipulation and splinting of the fractures using a hematoma block in the office

3. Remanipuation and casting in the operating room under general anesthesia

4. Open reduction and internal fixation of the radius fracture under general anesthesia

 

DISCUSSION-The radiographs show a distal radial shaft fracture. The distal radial physis appears to be nearly or completely closed, so significant remodeling of the residual bayonette apposition should not be expected.

The patient has already attempted manipulation, and remanipulation, whether in an office setting or under general anesthesia, is unlikely to maintain an adequate reduction. In this age group treatment of radial shaft fractures with internal fixation provides the most definitive outcome, posing the least risk for repeat surgery, and allows early rehabilitation. PREFERRED RESPONSE: 4

 

Question 18-A displaced pediatric supracondylar humerus fracture is treated with closed manipulation and placement of 2 Kirschner wires placed from the lateral side. What would be the effect of adding a third pin from the lateral side?

 

1. Increase risk for iatrogenic ulnar nerve injury

2. Provide more construct stiffness than adding a medial pin

3. Improve construct stiffness in the presence of medial column comminution

4. Will not affect construct stiffness in the presence of residual distal fragment internal rotation

 

DISCUSSION-Multiple biomechanical studies have shown that the addition of a third pin from the lateral side improves construct stiffness in the presence of medial column loss or slight internal rotation of the distal fragment.The same studies show that addition of a medial pin (cross pinning) has essentially the same benefit.Placement of a medial pin increases risk for iatrogenic nerve injury.

PREFERRED RESPONSE: 2

 

Question 19-Nonossifying fibroma (NOF) is best characterized as

1. an eccentric scalloped metaphyseal radiolucent lesion.

2. producing a fallen leaf sign.

3. a central metaphyseal radiolucent lesion with fusiform expansion to the width of the physis.

4. having a ground glass appearance.

 

DISCUSSION-NOF lesions are eccentric and scalloped. Unicameral bone cysts (UBC) are central cystic lesions that expand to the width of the physis. When UBCs fracture, a fragment of bone can be seen in the cyst; this is called the fallen leaf sign. A ground glass appearance is seen in fibrous dysplasia. PREFERRED RESPONSE: 1

 

RESPONSES FOR QUESTIONS 20 THROUGH 27

1. Preoperative evaluation by cardiology and pulmonary

2. Preoperative evaluation by pulmonary and nutrition

3. MRI scan of spinal axis

4. Preoperative evaluation by a hematologist

5. Flexion/extension lateral C-spine radiographs

6. Preoperative evaluation by cardiology and an MRI scan of the spinal axis

 

For each of the clinical scenarios below, match the most appropriate preoperative work-up or evaluation.

Question 20-A 14-year-old girl with a 65-degree scoliosis with café au lait cutaneous lesions and axillary freckling.

PREFERRED RESPONSE: 3

Question 21-A 14-year-old boy with Duchene muscular dystrophy and a 48-degree scoliosis.

PREFERRED RESPONSE: 1

Question 22-A 13-year-old girl 1 year postmenarche with a 58-degree left thoracic curve.

PREFERRED RESPONSE: 3

Question 23-A 15-year-old tall, thin girl with positive wrist and thumb signs and a 65-degree scoliosis.

PREFERRED RESPONSE: 6

Question 24-A 16-year-old with cerebral palsy and an 80-degree neuromuscular curve with a body weight below the5th percentile.

PREFERRED RESPONSE: 2

Question 25-A 9-year-old girl with a 57-degree early-onset scoliosis who failed bracing preoperatively for growing rods.

PREFERRED RESPONSE: 3

Question 26 -An 8-year-old girl with Morquio syndrome with a 65-degree scoliosis for growing rods.

PREFERRED RESPONSE: 5

Question 27-A 13-year-old boy with a 58-degree scoliosis and Down syndrome.

PREFERRED RESPONSE: 5

DISCUSSION FOR QUESTIONS 20 THROUGH 27

Scoliosis in the setting of these cutaneous abnormalities is likely occurring in a patient with neurofibromatosis. Prior to surgery in patients with neurofibromatosis, a preoperative MRI scan is helpful to assess for dural ectasia and intraspinal neurofibromas. Patients with Duchenne muscular dystrophy develop impairment of both pulmonary and cardiac function and need pulmonary and cardiac evaluation on an ongoing basis. Spinal fusion surgery should not be performed in these patients without cardiology and pulmonary evaluations before surgery. Left thoracic curves, like all atypical scoliosis conditions, require evaluation before surgery with an MRI scan of the spinal axis to rule-out intraspinal canal abnormalities such as a syrinx. Scoliosis in the setting of arachnodactyly strongly suggests Marfan syndrome. Patients with Marfan syndrome may have dural ectasia and

 

require an MRI scan before spinal fusion surgery. In addition, cardiac abnormalities may also be present, and echocardiography is indicated to rule-out aortic abnormalities. A child with cerebral palsy should be evaluated by both pulmonary and the nutrition service before spinal fusion surgery, especially if the patient’s weight is below the 5th percentile. Although formal pulmonary function testing may not be possible in patients with cerebral palsy, evaluation of the patient’s cough and general pulmonary status is important to assess surgical risk and postsurgical pulmonary problems. Early-onset scoliosis constitutes atypical scoliosis, and studies have confirmed a higher incidence of intraspinal canal abnormalities in patients with atypical scoliosis.

An MRI scan is indicated to rule out intraspinal pathology before instrumenting the spine in these patients. Skeletal dysplasia syndromes may be associated with ligamentous laxity and C1-C2 instability,and this is specifically associated with Morquio mucopolysaccharidosis syndrome. Upper-cervical-spine instability needs to be investigated before proceeding with spinal fusion for scoliosis. Radial longitudinal deficiencies are associated with thrombocytopenia and Fanconi anemia, and careful evaluation before any surgeries are performed in these patients is needed to preclude a bleeding disorder. Down syndrome is associated with ligamentous laxity and upper-cervical-spine instability. Ruling-out C1-C2 instability is necessary for these patients before spinal fusion.

 

 

 

Question 28-What is the most likely complication associated with the injury shown in Figure 28?

1. Infection

2. Malunion with development of varus deformity

3. Chondrolysis

4. Osteonecrosis of the femoral head

 

DISCUSSION-This radiograph shows a Delbet type II fracture of the femoral neck. Osteonecrosis is the most common complication following hip fracture in children. Varus deformity is the second-most-common complication. Nonunion occurs less frequently than coxa vara. Chondrolysis and infection are relatively rare complications. Osteonecrosis is most likely the result of vascular injury that occurs at the time of fracture. Type I, II, and III fractures were 15, 6, and 4 times more likely, respectively, to result in osteonecrosis than were type IV fractures. Disruption of blood flow

may be caused by kinking or tearing of the vessels occurring with fracture displacement or by direct laceration of blood vessels by fracture fragments. PREFERRED RESPONSE: 4

 

Question 29- is the photograph of a 7-month-old infant. What is the mode of inheritance?

 

 

 

1. X-linked recessive

2. Autosomal-recessive

3. Maternal mitochondrial DNA

4. Autosomal-dominant

 

DISCUSSION-Postaxial polydactyly is a common autosomal-dominant trait seen in approximately 1 in 200 births in the United States, usually with a positive family history, although foot polydactyly is less common than hand polydactyly. The other modes of inheritance are not applicable. This condition is not associated with other systemic disorders when the remainder of the physical examination is normal, so no further workup is needed. Children with postaxial polydactyly of the foot exhibit normal motor milestones. Elective surgical

reconstruction is performed to improve cosmesis and shoe wearing, and can be done at any age in accordance with the cultural and social expectations of the family.

PREFERRED RESPONSE: 4

 

Question 30-Figures 30a and 30b are the radiographs of a 10-year-old ambulatory patient with arthrogryposis who fell 2 days ago and sustained an injury to the left knee. Physical examination revealed pain in the anterior knee, a large knee joint effusion, and an inability to straighten the knee. What is the most appropriate treatment?

 

 

1. Open reduction and internal fixation of the fragments with a suture placed in the quadriceps tendon and through patellar bone tunnels

2. Placement of an above-knee cast with the knee extended, and limited weight bearing for 6 weeks

3. Placement of a knee immobilizer and weight bearing as tolerated for 6 weeks

4. Open reduction and direct repair of the quadriceps tendon with sutures

 

DISCUSSION-The radiographs reveal a small rim of bone avulsed proximally from the patella. This represents a superior patellar sleeve fracture. In an ambulatory patient the extensor mechanism must be repaired to function properly. Consequently, immobilization only, either in a cast or knee immobilizer, would not be appropriate. The fracture is distal to the quadriceps tendon insertion. The proximal avulsed fragment likely contains a significant portion of cartilage, which cannot be appreciated on the radiographs. The repair should be made between the bony fragments, usually through bone tunnels in the larger distal fragment. PREFERRED RESPONSE: 1

 

 

 

Question 31-Figure 31 is the T2-weighted MRI scan of an 11-year-old boy with a 7-day history of limping, pain in his right leg, and fevers. His MRI scan reveals soft-tissue swelling. The distal femur is tender to palpation,but there is no pain with hip or knee range of motion. He is unable to bear weight on his right leg. His temperature is 38.8°C, pulse 110, and blood pressure 120/70 mm Hg. Lab study results revealed a white blood cell count of 16000 cells/μL (reference range, 4500-11000 cells/μL), hematocrit 30% (reference range, 41%-50%), and C-reactive protein of 20 mg/L (reference range, 0.08-3.1 mg/L). A gram stain from a blood culture obtained in the emergency department showed gram plus cocci in clusters. What is the most appropriate empiric antibiotic treatment?

 

1. Vancomycin

2. Cephalexin

3. Oxacillin

4. Imipenem

 

 

DISCUSSION-This patient has findings consistent with acute osteomyelitis caused by Staphylococcus aureus. His clinical presentation strongly suggests the causative organism will be methicillin-resistant Staphylococcus aureus (MRSA). A recent study identified 4 independent predictors (temperature > 38.0 C, white bloodcell count > 12000 cells/μL, hematocrit < 34%, and C-reactive protein > 13 mg/L) to reliably differentiate between MRSA and MSSA osteomyelitis. The predicted probability of MRSA osteomyelitis is 92% if all 4 predictors are present (as in this case), 45% if 3 are present, 10% if 2 are present, 1% if 1 predictor is present. Empiric treatment should include an antibiotic active against MRSA, such as vancomycin.

-(Oxacillin, cephalexin, and imipenem are active against MSSA, but not MRSA. PREFERRED RESPONSE: 1

 

CLINICAL SITUATION FOR QUESTIONS 32 AND 33

Figures 32a through 32c are the radiograph, bone scan, and MRI scan of a 15-month-old infant. Intravenous antibiotics were initiated 2 days ago in response to blood cultures that were positive for Staphylococcus aureus. Since antibiotic initiation, his fever dropped from a maximum of 39.4°C to

37.2°C with occasional mild spikes. The hospitalist noticed that the baby’s left upper extremity was not moving.

 

 

 

Question 32-What is the next step in orthopaedic management of this condition?

1. Vital sign monitoring every 2 hours for temperature spikes

2. Peripheral indwelling central catheter placement for 6 weeks of intravenous antibiotics

3. CT scan to further delineate metaphyseal changes

4. Drainage of the gleno-humeral joint and debridement of the humerus

 

PREFERRED RESPONSE: 4

Question 33-What do the bone scan findings represent?

1. Sequestrum

2. Involucrum

3. Osteonecrosis

4. Heterotopic ossification

 

PREFERRED RESPONSE: 3

DISCUSSION FOR QUESTIONS 32 AND 33

The bone scan shows no uptake of the tracer, which indicates osteonecrosis. The MRI scan of the shoulder reveals sepsis with a focus on osteomyelitis. A CT scan will not add more useful information and will delay treatment. A sequestrum is a piece of dead bone that has become separated from normal/solid bone during the osteonecrosis process. It appears as a radiopacity on plain radiograph. The involucrum is new bone formed by an elevated periosteum and can be seen on radiograph.

Heterotopic ossification appears as radiopacity within the soft tissues. Late recognition of pediatric shoulder sepsis has been reported, and damage to the joint can be extensive. Septic joints are one of the few true orthopaedic emergencies. The methodology of drainage in shoulder sepsis is controversial (aspiration vs open drainage vs arthroscopic lavage), but the joint must be drained and sterilized to prevent cartilage damage.

 

Question 34-Physical examination of a 6-week-old infant revealed a positive left Galeazzi sign. With hip abduction to 80 degrees, there was a palpable clunk on the left but none on the right. Ultrasound imaging showed a right hip alpha angle of 60 degrees with 50% coverage of the femoral head; the left hip alpha angle was 40 degrees with 10% coverage of the femoral head. What is the most appropriate treatment for this problem?

 

1. Full-time placement of a Pavlik harness with follow-up in 1 week

2. Full-time placement of a Pavlik harness with follow-up examination and ultrasound in 3 months

3. Observation with follow-up at age 6 months with hip radiographs

4. Double diapering with follow-up examination and ultrasound in 1 month

 

DISCUSSION-This infant has a developmentally dislocated hip that is reducible (Ortolani positive) with an abnormal ultrasound. At age 6 weeks, this should be treated with a full-time Pavlik harness. Observation is likely to lead to a rigidly dislocated hip not amenable to bracing. Double diapering has no treatment effect in true developmental hip dysplasia/dislocation. Infants with unstable hips need to be checked every 1 to 2 weeks until the hip is stable. Follow-up in 3 months is not appropriate for an unstable hip. PREFERRED RESPONSE: 1

 

Question 35-In patients treated with growing rods for early-onset scoliosis, which of the following outcomes has been shown to occur over time with subsequent lengthening procedures?

1. Distraction force required increases, length obtained at each procedure decreases

2. Distraction force required increases, length obtained at each procedure increases

3. Distraction force required decreases, length obtained at each procedure increases

4. Distraction force required decreases, length obtained at each procedure decreases

 

DISCUSSION-In a prospective study of 60 growing rod lengthening procedures to treat early-onset scoliosis, detailed measurements of the amount of distraction force required and length gained during the procedure were taken. The forces required to distract the spine increased over time, and mean length achieved with each distraction decreased. By the fifth lengthening, required distraction forced had doubled vs baseline, and fewer than 8 mm of growth was achieved with each subsequent lengthening. PREFERRED RESPONSE: 1

 

 

 

Question 36-is the sitting radiograph of a 12-year-old boy with Duchenne muscular dystrophy who has a38-degree scoliosis and pulmonary function tests showing a forced vital capacity of 50% of the predicted percentage. His cardiac status is stable. When is the best time to perform spinal fusion surgery?

 

1. When his pulmonary function tests decline to 35% of predicted value

2. When his cardiac status starts to decline

3. When his scoliosis reaches 50 degrees

4. As soon as possible

 

DISCUSSION -Timing of surgery in patients with Duchenne muscular dystrophy is based on the patient’s pulmonary and cardiac status and not the severity of scoliosis. Because more than 90% of these boys will develop scoliosis and pulmonary function declines throughout their lives, operating before the pulmonary function tests decline too significantly enhances the likelihood of successful weaning from the ventilator postsurgically and minimizes the possibility of a tracheostomy. The Cobb angle measurement is superseded in this diagnosis by the cardiopulmonary status of the patient, making the response “When his scoliosis reaches 50 degrees” wrong.

Pulmonary function testing at 35% of predicted value is the absolute

threshold for surgery and a reasonable expectation for a successful wean off the ventilator, so surgery should ideally be done before this time. PREFERRED RESPONSE: 4

 

 

Question 37-is the photograph of a 10-year-old girl standing without shoes who underwent surgical correction of a left clubfoot deformity at age one. The family is concerned that her left lower extremity is smaller than the right. What is the etiology of the size difference between the left and right?

 

1. Tethered cord

2. Lumbar scoliosis

3. Intrinsic hypoplasia of the left lower extremity

4. Hemihypertrophy of the right lower extremity

 

DISCUSSION -Smallness of the entire lower extremity is intrinsic to clubfoot deformity. Multiple etiologies for size difference have been investigated to include vascular, neurologic, and difference in tissue type. Arterial abnormalities in clubfeet appear to produce a deletion phenomenon. Arteriography has shown that a larger percentage of clubfeet have abnormal arterial patterns, with the posterior tibial artery being the predominant vascular supply. Studies suggest that the absence of peripheral nerves or denervation decreases the rate of bone maturation, and this effect may be responsible for the diminished size of denervated limbs and may explain this phenomenon in

clubfoot. However, bone age has been found to be similar in those with clubfoot and controls. Tethering of the cord has not been found to be associated with idiopathic clubfoot. The majority of clubfeet have relatively normal muscle fibers. Hemihypertrophy of the contralateral limb is not associated with clubfoot deformity. PREFERRED RESPONSE: 3

 

RESPONSES FOR QUESTIONS 38 THROUGH 43

1. Pavlik harness treatment

2. Immediate spica casting

3. Titanium elastic intramedullary nailing

4. Submuscular bridge plating

5. Antegrade femoral nailing with a trochanteric entry intramedullary nail

For each of the following fractures, select the most appropriate treatment from the list of responses above.

Question 38-A 3-month-old infant with a displaced spiral midshaft femur fracture.

PREFERRED RESPONSE: 1

Question 39-A 16-year-old boy with a transverse midshaft femur fracture.

PREFERRED RESPONSE: 5

Question 40-A 2-year-old girl with a displaced spiral midshaft femur fracture.

PREFERRED RESPONSE: 2

Question 41-A 37-kg 9-year-old boy with a transverse midshaft femur fracture.

PREFERRED RESPONSE: 3

 

Question 42An 8-year-old boy with a severely comminuted and length-unstable midshaft femur fracture.

PREFERRED RESPONSE: 4

Question 43-A 9-year-old boy who was in a motor vehicle collision and sustained a head injury and grade 1 open transverse midshaft femur fracture.

PREFERRED RESPONSE: 3

DISCUSSION FOR QUESTIONS 38 THROUGH 43

The treatment of pediatric femur fractures varies with the child’s age and fracture characteristics. Children from birth to age 6 months are treated with Pavlik harness application, which provides adequate pain relief and alignment for the short duration required for healing in this age group.

Between 6 months and 5 years of age, most children are treated with immediate spica casting. While there may be some exceptions (with heavier children undergoing titanium elastic nail fixation), this has been more a matter of anecdote than study. While traction remains a treatment option for many femur fractures, many centers have moved away from it because of the associated costs, both to payers and families, and the good results achieved with other methods. Because traction remains a viable

 

treatment option for many femur fractures, it was left out of the suggested responses. Children age 5 to 11 with appropriate fractures are by and large treated with titanium elastic intramedullary nails. One exception is children with severely comminuted and length-unstable femur fracture, for whom titanium elastic nails may be less reliable and submuscular bridge plating is an excellent choice. Titanium elastic nails have also been used without undue complications in the treatment of low-grade open femur fractures, and may offer advantages over external fixation such as improved wound access and decreased refracture rates. For children older than age 11, rigid antegrade nailing through a trochanteric entry point is common. The use of a piriformis entry nail is not recommended in children.

 

Question 44-A 3-year-old girl was evaluated for toe walking. Her history was remarkable for prematurity with known intracranial hemorrhage. Her recent neurologic workup included a brain MRI scan showing periventricular leukomalacia. She walked at age 2. Gait examination revealed a crouched gait on tiptoes with knees and hips flexed. Passive range-of-motion testing revealed hip flexion contracture of 5 degrees,hamstring contracture of 15 degrees on popliteal angle testing, and ankles dorsiflex to neutral in knee extension and 15 degrees above neutral in knee flexion. Initial treatment should consist of

 

1. percutaneous Achilles lengthening.

2. open Achilles tendon lengthening.

3. ankle bracing and therapy.

4. steroid therapy.

 

DISCUSSION -Bracing and therapy are the best initial treatments. The history and examination reveal spastic diplegia GMFCS-II grade, which is a static brain injury that is not progressive. Brain MRI scan findings of periventricular leukomalacia are often seen in spastic diplegia. Her examination shows mild contractures on range-of-motion testing. The ankle range of motion examination shows a gastrocnemius contracture;dorsiflexion is much improved in knee flexion. With a true Achilles contracture, ankle dorsiflexion does not improve in knee flexion. Her history does not support muscular dystrophy, for which steroid therapy can improve short-term function. Surgery is not indicated at this age with this amount of contracture. PREFERRED RESPONSE: 3

 

Question 45-What is the minimum hours per day of wear that has been correlated with the effectiveness of bracing on curve progression in idiopathic scoliosis?

 

1. Prescribed brace wear 23 hours/day

2. Prescribed brace wear 16 hours/day

3. Actual brace wear more than 12 hours/day

4. Actual brace wear 6 hours/day

 

DISCUSSION -The efficacy of brace treatment for patients with adolescent idiopathic scoliosis is controversial because its effectiveness remains unproven. One of the challenges is patient noncompliance with prescribed bracing regimens. A recent study investigated curve progression based on actual brace wear using a temperature sensor to accurately assess brace wear. The total hours of brace wear correlated with lack of curve progression with a dose-response effect noted.

Curves did not progress in 82% of patients who actually wore the brace more than 12 hours per day. For those who wore the brace for fewer than 7 hours per day,curves progressed in 69%. Prescribed bracing regimens (eg, 16 hours/day or 23 hours/day) had no effect on actual brace wear or curve progression.

 

Question 4-Children develop hand dominance by approximately what age?

1. 6 months to 9 months

2. 12 months to 18 months

3. 2 years to 3 years

4. 4 years to 5 years

 

DISCUSSION -Most children develop hand dominance during their third year. Although there is individual variation in age of development of handedness, infants and toddlers are normally

 

ambidextrous. Strong hand preference in a child younger than age 2 may indicate a neurological deficit. Persistence of ambidexterity is not pathological. PREFERRED RESPONSE: 3

 

 

 

Question 47-What is the structure marked by the “B” on Figure 47?

1. Illium

2. Femoral head

3. Triradiate cartilage

4. Labrum

 

DISCUSSION-This is a coronal flexion view of a hip ultrasound. It is often best interpreted as an anteroposterior view rotated 90 degrees to the left. The femoral head is the large circular structure (B) surrounded by the acetabulum. The ilium (A) forms the roof. The triradiate cartilage(C) and ischium

(D) form the medial wall. PREFERRED RESPONSE: 2

 

 

 

Question 48-Figure 48 is the radiograph of an 11-year-old boy who fell directly on his left shoulder while riding a bicycle. He complained of pain in his left shoulder. An MRI scan of the injury is likely to reveal what findings?

 

1. Disruption of the coracoclavicular ligaments

2. Dislocation of the acromioclavicular joint

3. Impingement of the inferior fragment on the brachial plexus

4. Intact periosteal sleeve inferiorly

 

DISCUSSION -In children, fractures of the distal clavicle are almost always through the distal physis

and adjacent metaphysis, and, consequently, the acromioclavicular joint is rarely dislocated. The coracoclavicular ligaments usually remain attached to the thick periosteum on the undersurface of the clavicle and are rarely damaged. Because of the thick periosteum and intact ligaments, these fractures are inherently stable and heal well with conservative treatment. In contrast, similar injuries in adults pose a higher risk for surgical intervention. PREFERRED RESPONSE: 4

 

 

 

Question 49-a is the photograph of the axilla and Figure 49b is the radiograph of the spine of a 13-year-old child referred for scoliosis treatment by a school screening program. What is the most likely diagnosis?

 

1. Idiopathic scoliosis

2. Nondystrophic scoliosis in neurofibromatosis I (NF1)

3. Nondystrophic scoliosis in NF2

4. Dystrophic scoliosis in NF2

 

DISCUSSION -Scoliosis is the most common skeletal manifestation of NF1. Nondystrophic scoliosis is less common than dystrophic scoliosis. Its

clinical appearance and behavior mimic idiopathic scoliosis. Dystrophic scoliosis is recognized earlier than nondystrophic. It is characterized by a sharp angular curve involving 4 to 6 vertebrae. Its clinical appearance and behavior mimic idiopathic scoliosis. Scoliosis is not found in NF2. Axillary freckling is common in NF1 or NF2.

 

PREFERRED RESPONSE: 2

 

 

Question 50-The AP radiograph of a 5-year-old boy shows a 20-degree left thoracic scoliosis. He was noted by his pediatrician to have asymmetry on a forward bend test. On examination he is neurologically intact except for decreased sensation on the lateral aspect of both flanks and to pinprick in both hands. He has no pain.What is the best initial step in treatment at this time?

1. Observation

2. Initiate bracing

3. MRI scan of the entire spine

4. Spinal instrumentation with growing rod construct

 

DISCUSSION -This patient has atypical scoliosis, given his young age and left thoracic curve. In addition, he has abnormal neurologic findings. MRI scan to evaluate for neural axis abnormalities is indicated. Abnormal MRI findings are present in 2% to 3.8% of all patients with presumed idiopathic scoliosis. Abnormal MRI findings are more likely if specific clinical factors are present, such as absence of thoracic apical segment lordosis, atypical curve pattern, an abnormal neurologic examination, male gender, and age younger than 11. In a patient with an atypical curve and neurologic indicators, the yield of MRI scan for a neuraxis abnormality has been shown to be 25%. This patient had both syringomyelia and a Chiari malformation that were treated neurosurgically.

Observation would have missed these findings. Bracing or spinal instrumentation may eventually be treatment options for scoliosis given his young age, but establishing a diagnosis first with an MRI scan of the spine is the most appropriate initial step. PREFERRED RESPONSE: 3

 

CLINICAL SITUATION FOR QUESTIONS 51 AND 52

Figures 51a and 51b are the radiographs of a 12-year-old girl who fell off her bicycle.

 

 

Question 51-What is the most appropriate initial treatment?

1. Closed reduction and spica cast

2. Anatomic reduction, compression fixation, and spica immobilization

3. Crutches and nonweight-bearing activity for 6 weeks

4. Percutaneous Kirschner wire fixation

PREFERRED RESPONSE: 2

Question 52-What is the incidence of osteonecrosis in the injury shown in Figures 51a and b?

1. 25%

2. 50%

3. 75%

4. 100%

PREFERRED RESPONSE: 2

DISCUSSION- Fractured hips in a child demand anatomic reduction with compression fixation. This type of fracture is mildly displaced and can usually be closed, reduced, and pinned. A hip spica cast is recommended to prevent loss of reduction. Open reduction is recommended in a displaced fracture that cannot be reduced. Kirschner wire fixation is not adequate. Osteonecrosis is the most common complication of hip fractures in children. It occurs in 50% of transcervical fractures similar to the one

 

 

 

shown in the radiographs. It also occurs in 100% of transepiphyseal fractures, 25% of cervico-trochanteric fractures, and 10% to 15% of peritrochanteric fractures.

 

Question 53-Figure 53 is the anteroposterior radiograph of a child’s fractured tibia. The parents want to know why the bone is abnormal. Why is the bone “thicker”?

 

1. Increased bone remodeling

2. Decreased hydroxyapatite

3. Decrease in the number of osteoblasts

4. Decrease in the acidification of Howship’s lacuna

 

DISCUSSION -Albers-Schonberg disease or osteopetrosis is caused by an inability of the osteoclast to acidify Howship’s lacuna. The lack of hydrochloric acid causes incomplete dissolution of hydroxyapatite and incomplete remodeling. The bone remains disorganized and thick. This condition is not diagnosed in some patients with osteopetrosis until a fracture occurs.

Osteoblast activity is not decreased in the condition. PREFERRED RESPONSE: 4

 

 

 

Question 54-Figure 54 is the lateral radiograph of an 8-month-old infant whose mother reports he has not been moving his left leg for 2 to 3 days. His mother denies any known trauma, and says he has not been febrile or ill-appearing. The mother says her infant spends a significant amount of time being cared for by her boyfriend and attending a daycare facility. What is the most likely cause of his injury?

 

1. Vitamin D deficiency

2. Nonaccidental trauma

3. Osteogenesis imperfecta

4. Osteomyelitis

 

DISCUSSION -The radiograph reveals a supracondylar femur fracture in an infant. There is evidence of early fracture healing. All femur fractures in children under age 3 should receive a higher index of suspicion for nonaccidental trauma. Considering that this injury was not witnessed and the child has been cared for by multiple parties other than the mother who brought him to the emergency department, an immediate consultation with child protective services is appropriate. There is no radiographic evidence of rickets, as would be seen in vitamin D deficiency.

 

 

Fractures in patients with osteogenesis imperfecta are typically diaphyseal. There is no evidence of osteomyelitis. PREFERRED RESPONSE: 2

 

Question 55-Figures 55a and 55b are the radiographs of a 5-year-old boy 6 weeks after he was treated for a minimally displaced tibia fracture in a long-leg cast that was recently removed by his pediatrician. He has been afebrile and

laboratory evaluation reveals a white blood cell count of 8.3 x109/L (reference range, 4.5-11.0 x109/L), C-reactive protein of < 0.5 (reference range, 0.08-3.1 mg/L), and erythrocyte sedimentation rate of 2 mm/h (reference range, 0-20 mm/h). In addition to axillary freckling, what physical examination finding is most likely to be present in this patient?

 

1. Posteromedial bowing of his contralateral tibia

2. Multiple café-au-lait spots on his trunk and extremities

3. Calcaneal valgus deformity of the foot

4. Visual disturbance attributable to glaucoma

 

DISCUSSION -Congenital pseudoarthrosis is a rare condition occasionally found in patients with neurofibromatosis (NF). The diagnosis can sometimes be made with progressive anterolateral bowing of the tibia, but often presents as a fracture through the residual dysplastic tibia that presents with nonhealing. Patients with NF1 commonly have axillary and groin freckling, multiple café-au-lait spots, optic gliomas, and Lisch nodules. Other orthopaedic manifestations include scoliosis, cervical spine abnormalities, and other bone dysplasias or pseudoarthrosis (clavicle, radius). NF and congenital pseudoarthrosis are associated with anterolateral bowing of the tibia, not posteromedial bowing, which can be associated with calcaneal valgus deformity of the foot. In addition, NF is associated with optic glioma visual disturbances, not glaucoma. PREFERRED RESPONSE: 2

 

 

 

Question 56-Figures 56a and 56b are the MRI scans of a 2-year-old girl who has a fever of 39°C and inability to move her left arm. She has not had any recent injury and is otherwise healthy. Radiograph findings of her left upper extremity are normal. What is the most appropriate treatment?

 

1. Incision and drainage of the humerus

2. Sling immobilization of the left upper extremity

3. Total body bone scan

4. A course of oral antibiotics and recheck in 1 week

 

DISCUSSION-The MRI scan shows a large abscess along most of the humerus. Incision and drainage of the abscess is indicated. A bone scan will not add any additional information regarding location of the problem.Immobilization will not address the origin of the problem. Oral antibiotics are not adequate for this abscess.

 

PREFERRED RESPONSE: 1

 

 

 

Question 57-is the lateral radiograph of a 14-year-old obese boy who sustained an injury to his right knee while playing soccer. He has a large effusion and pain with any motion. The decision is made to perform surgery. What structure is most likely to be interposed in the fracture site?

 

1. Medial meniscus

2. Intermeniscal ligament

3. Lateral meniscus

4. Osteochondral fragment

 

DISCUSSION-Records of a consecutive series of 80 skeletally immature patients (mean age, 11.6 years; range, ages 5 and internal fixation of type 3 tibial eminence fractures (57) or type 2 fractures that did not reduce in extension (23) between 1993 and 2001 were reviewed. Entrapment of the anterior horn of the medial meniscus(36), intermeniscal ligament (6), or anterior horn of the lateral meniscus (1) was seen in 26% (6 of 23) of type 2 fractures

and 65% (37 of 57) of type 3 fractures. An associated meniscal tear was seen in 3.8% of patients (3 of 80). Meniscal entrapment is common in patients with type 2 and 3 tibial eminence fractures.Arthroscopic or open reduction should be considered for type 3 fractures and for type 2 fractures that do not reduce in

extension to remove the incarcerated meniscus, allowing for anatomic reduction. PREFERRED RESPONSE: 1

Question 58-is the radiograph of a 5-year-old boy who has left thigh pain. What is the most appropriate treatment?

 

1. Valgus osteotomy with internal fixation

2. Curettage and allograft

3. Observation

4. Spica casting

DISCUSSION-This child has symptomatic fibrous dysplasia as evidenced by the coxa vara and ground-glass appearance.

Lucency is also seen more distally in the femoral shaft. He already is symptomatic and is likely to

progress to more severe deformity with observation alone. Although surgery may need to be repeated,corrective osteotomy and fixation are most appropriate. Allograft bone is likely to be resorbed in fibrous dysplasia. Casting is unlikely to relieve symptoms for long. Biopsy can be performed in conjunction with surgical correction. PREFERRED RESPONSE: 1

 

 

 

 

 

Question 59-are the radiographs of a 7-year-old boy who was seen 1 week after he underwent a closed reduction and casting in the emergency department after a fall on an outstretched arm. What is the most appropriate next step for this patient?

 

 

1. Observation

2. Repeat closed reduction and casting

3. Open reduction and plate fixation

4. Closed reduction and intramedullary nail fixation

 

DISCUSSION -This child’s radiograph shows an acceptably reduced fracture of both the radius and ulna. Generally accepted limits of shaft angulation for cast treatment for girls 8 years of age or younger and boys age 10 or younger are 20 degrees for distal-third, 15 degrees for middle-third, and 10 degrees for proximalthird fractures. Remodeling decreases as one goes from distal to proximal in the forearm. Unless the child’s fracture deviates from these criteria, surgical treatment is not necessary. Because of the risk of displacement, however, close follow-up is recommended.

 

PREFERRED RESPONSE: 1

 

Question 60-A 3-year-old boy who was treated with Ponseti-method casting demonstrates supination of the affected foot during swing phase of gait. His ankle has 20 degrees of active and passive dorsiflexion and 45 degrees of plantar flexion. What is the most appropriate treatment?

1. Anterior tibialis tendon lengthening

2. Anterior tibialis tendon transfer to a dorsal lateral foot position

3. Anterior tibialis tendon transfer through the interosseous membrane to the calcaneus

4. Posterior tibialis tendon transfer through the interosseous membrane to the dorsum of the foot

 

PREFERRED RESPONSE: 2-DISCUSSION-Dynamic supination is a known residual problem after the Ponseti casting technique is used. Ponseti applied the principles of the Garceau procedure and transferred the entire anterior tibialis tendon to the lateral cuneiform. The anterior tibialis continues to act as a dorsiflexor of the foot but with a more advantageous trajectory. Lengthening the anterior tibialis by itself will not redirect the pull of the muscle. Likewise, the posterior tibialis tendon transfer through the interosseous membrane will not address the supinating force of the anterior tibialis. It is used when the anterior and lateral compartment muscles are either not functioning or weak in relationship to the posterior tibialis. The anterior tibialis tendon transfer to the calcaneus has been used successfully in myelodysplasia for calcaneal deformity.

 

Question 61-The majority of cases of osteogenesis imperfecta (OI) are caused by mutations in genes that encode

1. fibrillin.

2. type I collagen.

3. type II collagen.

4. fibroblast growth factor receptor (FGFR)-3.

 

DISCUSSION-OI is caused by mutations in type I collagen genes COL1A1 or COL1A2 in 85% of cases; the remainder of mutations are in collagen-associated proteins that destabilize the organic bone matrix. Marfan syndrome is caused by mutations in fibrillin. A variety of epiphyseal dysplasias such as multiple epiphyseal dysplasia have type II collagen mutations. Achondroplasia is caused by a mutation in FGFR-3. PREFERRED RESPONSE: 2

 

Question 62-What genetic defect is responsible for achondroplasia?

1. Trisomy of chromosome 21

2. Defect in collagen, type 1, alpha 1 (COL1A1)

3. Defect in fibroblast growth factor 3 (FGF-3)

4. Defect in fibroblast growth factor receptor 3 (FGFR-3)

 

DISCUSSION -In achondroplasia the defect is always in the same location on this gene (a defect in FGFR-3), and most children share a very similar clinical phenotype. Achondroplasia is not caused by a defect in the gene for FGF-3, the growth factor itself, but rather the gene coding for the receptor.

Trisomy of chromosome 21 is responsible for Down syndrome. Defects in the COL1A1 gene are found in some types of osteogenesis imperfecta. Unlike achondroplasia, the defects occur throughout the gene, with more than 200 mutation sites reported. PREFERRED RESPONSE: 4

 

 

 

Question 63-is the anteroposterior (AP) radiograph of a 12-year-old boy with type 3 spinal muscular atrophy(SMA) whose scoliosis has progressed despite bracing. Because of his curvature, it has become more difficult for him to support his trunk while sitting, and for the last 6 months he has required assisted ventilation at night. What is the most appropriate treatment?

 

1. Growing rod construct

2. Anterior spinal fusion with instrumentation

3. Posterior spinal fusion with instrumentation

4. AP spinal fusion with instrumentation

 

DISCUSSION-Surgery is recommended for scoliosis associated with SMA when curves progress beyond 50 to 60 degrees and are associated with impaired sitting balance and worsening pulmonary function. Continued bracing is unlikely to be effective. Anterior surgery alone is not recommended because it is associated with high rates of secondary curve progression in patients with SMA, and also may further impair pulmonary function. Because curves in SMA are relatively flexible, combined anterior and posterior surgery is usually required only for very large curves (more than 100 degrees) and very young patients (to prevent crankshaft phenomenon), and should be reserved for those without

 

significant pulmonary issues because of the pulmonary morbidity associated with an anterior procedure. In this case, for an older child with a 60-degree curve and developing pulmonary difficulties, posterior surgery alone is the best option.

 

PREFERRED RESPONSE: 3

 

Question 64-A 2-year-old boy was examined for flatfoot when standing. Gait examination revealed normal toddler gait with flat feet; in stance no arch is visible and heels are in 10 degrees of valgus. He has no pain. His arches reconstitute when seated or on tiptoe. Passive ankle dorsiflexion is 15 degrees in knee extension,plantar flexion is 50 degrees, and subtalar motion is 30 degrees. What is the most appropriate treatment?

 

1. Arch supports should be prescribed to help his feet develop.

2. Radiographs are needed to evaluate for deformities such as vertical talus or tarsal coalition.

3. Observation and education

4. Physical therapy should be prescribed to help his feet develop and stretch his tight Achilles tendons.

 

DISCUSSION-Flexible flat feet are a normal toddler variant. In the absence of pain or dysfunction, flat feet do not need treatment of any kind. Examination shows normal ankle motion, so Achilles stretching is not needed.His range-of-motion and gait examination does not suggest any abnormalities; therefore, radiographs are unnecessary.

 

PREFERRED RESPONSE: 3`

 

Question 65-Figures 65a and 65b are the initial radiographs of a 13-year-old boy who sustained an injury to his right knee while playing tackle football. He had immediate pain and the inability to bear weight. Open treatment of the injury was recommended and his postoperative radiograph is shown in Figure 65c. Heand his family should be advised that his risk for distal femoral physeal arrest is approximately

 

 

 

1. 10%.

2. 30%.

3. 60%.

4. 95%.

 

DISCUSSION-Multiple studies have shown a fairly high rate of physeal arrest following physeal injuries to the distal femur. Although individual studies list varying rates for physeal arrest, the overall rate is about 60%. The rate has been shown to be higher when the initial fracture is displaced.

 

PREFERRED RESPONSE: 3

 

Question 66-A 5-week-old infant was evaluated for a unilateral clubfoot. The parents are told their child will have Ponseti-type management of clubfoot. What is the best description of the initial phase of this treatment?

 

1. Weekly long-leg casts will be applied to first correct the cavus, adductus, and hindfoot varus components, and then a percutaneous Achilles tenotomy will be used to correct the equinus followed by a final cast.

2. Weekly short-leg casts will be applied to first correct the cavus, adductus, and hindfoot varus components, and then a brace will be used to correct the equinus.

3. Weekly long-leg casts will be applied to correct the equinus first, then an abduction brace will be used to correct the rest of the foot.

4. Weekly long-leg casts will be applied, abducting the forefoot by pushing against the calcaneocuboid joint until the foot is straight, and then the casts will focus on the equinus.

 

DISCUSSION-The Ponseti technique consists of weekly long-leg groin-to-toe casts that correct the components of the clubfoot in the order of cavus, forefoot adductus, hindfoot varus, and equinus. A percutaneous Achillestenotomy is needed to finish correcting the equinus in almost all cases because bracing a foot in equinus will lead to brace failure attributable to the foot sliding out or blistering. The Ponseti technique entails pushing against the laterally positioned talar head and reducing the foot around this fulcrum to the proper position of the talonavicular joint. The technique described in Response 3 is Kite’s method, which created a rocker-bottom foot. Short-leg casts are not used in the Ponseti method. PREFERRED RESPONSE: 1

 

Question 67-Laboratory examination of a 5-year-old boy who toe-walks and recently began tripping and falling revealed a creatine phosphokinase level 10 times higher than the normal level. He has one 11-yearold brother who walks normally. To confirm the diagnosis of Duchenne muscular dystrophy, a creatine phosphokinase test should be ordered on which family member?

 

1. Father

2. Mother

3. Brother

4. Sister

 

DISCUSSION-Creatine phosphokinase levels are elevated in this patient and the mother is the carrier. The father’s test result is always negative because this is a sex-linked disease. The brother’s test result will be normal because he does not have the disease. PREFERRED RESPONSE: 2

 

 

 

Question 68-shows a cast being removed from a child’s forearm. The risk of cast saw burn can be decreased by

 

1. sedating the child.

2. using fiberglass cast material.

3. using an alternative saw technique.

4. using a saw without a vacuum.

 

DISCUSSION--Although the heat generated may be related to the thickness of any material, fiberglass tends to generate more heat than plaster. A sedated patient cannot inform the practitioner of any discomfort during use of the saw. During the cutting of the cast depicted in the video, the saw never leaves the cast material. This

constant contact tends to produce more heat than an intermittent “up and down” technique. The saw vacuum has been shown to contribute to the cooling of the blade. PREFERRED RESPONSE: 3

 

 

Question 69-A 3-year-old girl with spastic right hemiparesis walks on her toes. Her right ankle can be dorsiflexed passively to 5 degrees short of neutral position. Her left ankle dorsiflexes actively and passively to +15 degrees. Botulinum toxin injections were given to her right calf 1 month before this examination. What is

 

the most appropriate treatment at this time?

1. Immediate fitting of right and left ankle-foot orthoses

2. Immediate fitting of a right ankle-foot orthosis

3. Percutaneous heel cord lengthening, right

4. Serial casting of the right foot and ankle

 

DISCUSSION-The patient walks in equinus on the unaffected left side in response to the deformity on the affected right side. Once the equinus is controlled on the hemiparetic side, the other side will be able to function properly and will not require orthotic management. Because of the development of the musculotendinous unit of the gastrosoleus complex, it is best to delay surgical intervention for equinus deformity until this child is at least 4 years of age. It will be difficult to obtain a properly fitting ankle-foot orthosis with even a mild fixed deformity. Serial casting with or without botulinum toxin injection is a useful technique to obtain a neutral ankle position and facilitate orthotic management.

PREFERRED RESPONSE: 4

 

Question 70-What is the most likely cause of an acute femur fracture in a 5-month-old child?

1. Metabolic bone disease

2. Birth trauma

3. Accidental trauma

4. Nonaccidental trauma (abuse)

 

DISCUSSION-Although femur fractures are common in children, fractures in nonambulatory children carry a very high specificity for abuse. Metabolic bone disease is less commonly a cause of femur fractures. Birth trauma,from which femur fractures have been reported, would have been healed by 5 months of age. Accidental trauma generally does not occur in nonambulatory children. Orthopaedic surgeons, like all physicians, are mandated to report suspected cases of child abuse.

PREFERRED RESPONSE: 4

 

 

 

Question 71-is the MRI scan of a 2-year-old girl who has been febrile for 1 week and has refused to bear weight on her left lower extremity for 3 days. Her entire left lower extremity is markedly swollen.Doppler ultrasound shows a deep venous thrombosis of the internal iliac vein. Her white blood cell count is 19000/μL (reference range, 4500-11000/μL) and her C-reactive protein level is higher than 20mg/L (reference range,

0.08-3.1 mg/L). If blood cultures yield positive results, what is the most likely

organism?

 

1. Methicillin-resistant Staphylococcus aureus

2. Salmonella typhii

3. Escherichia coli

4. Vancomycin-resistant Enterococcus

 

DISCUSSION-The clinical picture is one of infection and deep venous thrombosis. The MRI scan is consistent with osteomyelitis. Deep venous thrombosis in association with musculoskeletal infection is more common in osteomyelitis caused by methicillin-resistant Staphylococcus aureus. Presenting C-reactive protein levels generally are higher than 6 mg/L and are higher than with other causative organisms. The presence of the Panton-Valentine leukocidin gene encoded in strains of bacteria may explain the deep venous thrombosis.

PREFERRED RESPONSE: 1

 

Question 72-What is the most common type of skeletal dysplasia?

1. Diastrophic dysplasia

2. Multiple epiphyseal dysplasia

3. Nail patella syndrome

4. Achondroplasia

 

DISCUSSION-Achondroplasia is the most common skeletal dysplasia, with an incidence of 1/30,000 live births. The other choices are all more rare.

PREFERRED RESPONSE: 4

 

Question 73-A 13-year-old boy was evaluated for leg length difference. His pelvis balanced when a 1-inch (2.54 cm)block was placed under his left foot. History revealed he had a left distal femur physeal fracture treated with casting at age 10. Radiographs show normal limb alignment, but his left distal femoral physis is closed and his left femur is 2.5 cm shorter than the right. All other physes are open. His bone age is equal to his chronologic age. What surgical treatments will best equalize his discrepancy?

 

1. Right distal femoral and proximal tibia/fibula epiphysiodesis

2. Right distal femoral epiphysiodesis

3. Right proximal tibia/fibula epiphysiodesis

4. Left proximal tibia/fibula epiphysiodesis

 

DISCUSSION-Because the left distal femoral physis is closed with a leg length difference already at 1 inch,epiphysiodesis of both the right distal femur and proximal tibia/fibula is needed. The amount of correction will be the amount of growth remaining in the left proximal tibia. Presuming the standard rates of growth of 10 mm per year distal femur, 6 mm per year proximal tibia, and 4 mm per year distal tibia, this should yield a correction of 6 mm x 3 years = 1.8 cm by skeletal maturity at age 16.

This would leave the boy with an acceptable discrepancy of 7 mm, well under 1 inch/2.54 cm. Closing only the right distal femoral physis will leave the discrepancy unchanged at 1 inch/2.54 cm because no growth differential will exist.

Closing the right proximal tibia/fibular physis would mean the left knee will grow at 6 mm per year, but the right will grow at 10 mm per year. The discrepancy would increase by 4 mm per year, or 1.2 cm by skeletal maturity of age 16, leaving the boy 3.7 cm short on the left. Closing the left proximal tibia/

fibula physis would increase the discrepancy at the rate of 1.6 cm per year x 3 years because both the right femoral and proximal tibia/fibular physes would be growing, leaving the boy 4.8 + 2.5 = 7.3 cm shorter on the left leg.

 

PREFERRED RESPONSE: 1

 

Question 74-The main blood supply to the capital femoral epiphysis in a 10-year-old child is supplied from the

1. artery of the ligamentum teres.

2. epiphyseal branch of the lateral femoral circumflex artery.

3. posterosuperior and posteroinferior retinacular branches of the lateral femoral circumflex artery.

4. posterosuperior and posteroinferior retinacular branches of the medial femoral circumflex artery.

 

DISCUSSION-Before the age of 4 years, blood to the femoral head is supplied by the medial and lateral femoral circumflex arteries as well as the artery of the ligamentum teres. After the age of 4, the blood supply through the artery of the ligamentum teres diminishes. The lateral femoral circumflex system regresses,and its flow into the physis and epiphysis diminishes significantly so the medial femoral circumflex artery becomes the predominant blood supply to the metaphysis. The medial femoral circumflex artery provides the principal blood supply to the proximal femur via its posterosuperior and posteroinferior retinacular branches.

 

PREFERRED RESPONSE: 4

 

 

 

Question 75-Which muscles are responsible for the displacement of the proximal fragment of the fracture shown in Figure 75?

 

1. Iliopsoas, hip abductors, hip external rotators

2. Iliopsoas, hip adductors, hip internal rotators

3. Rectus femoris, hip abductors, hip external rotators

4. Hamstrings, hip abductors, hip internal rotators

 

DISCUSSION-The radiograph shows a subtrochanteric femoral shaft fracture in a skeletally immature patient. The proximal fragment is displaced into flexion, abduction, and external rotation. Flexion is attributable to the pull of the iliopsoas at the lesser trochanter. Abduction is attributable to the pull of the abductor muscles (gluteus medius and minimus) at the greater trochanter.

External rotation is attributable to the pull of the small external rotators, including the piriformis. The majority of the adductor musculature originates on the symphysis pubis and bypasses the proximal femur, inserting further distally on the adductor tubercle. The hamstrings originate on the ischial tuberosity and also bypass the proximal fragment, inserting distally on the proximal tibia and fibula. PREFERRED RESPONSE: 1

 

Question 76-What is the most common metatarsal fracture in a 3-year-old?

1. Proximal first metatarsal

2. Proximal fifth metatarsal

3. Distal second metatarsal

4. Distal fifth metatarsal

 

DISCUSSION -In children 5 years of age and younger, the proximal first metatarsal is the most common site for metatarsal fractures; the fractures are usually caused by a fall. In children older than age 5, injury to the fifth metatarsal is most common and is sustained during play or sports. Many fractures in children under age 5 are not initially visible on radiograph. Knowing where to look for common injuries is mandatory when treating young children and nonverbal patients.

PREFERRED RESPONSE: 1

 

CLINICAL SITUATION FOR QUESTIONS 77 AND 78

Figures 77a through 77c are the preoperative and postoperative radiographs of a 13-year-old boy who had sudden worsening of left hip pain following many months of mild pain. He was unable to walk because of his pain and underwent screw fixation.

 

 

Question 77-Use of the shorter, anterior screw may result in

1. deformity of the acetabular labrum when the hip is flexed.

2. injury to the femoral artery.

3. chondrolysis.

4. lack of stabilization of the epiphysis.

 

PREFERRED RESPONSE: 1

 

 

Question 78-Six weeks later the boy remains uncomfortable and continues to use crutches for all ambulation. What do the new radiographs seen in Figures 78a and 78b reveal?

1. Osteonecrosis

2. Chondrolysis

3. Fixation failure at the femoral neck

4. Screw cutout of the femoral head

 

PREFERRED RESPONSE: 3

DISCUSSION FOR QUESTIONS 77 AND 78

It has been demonstrated on a cadaver model that screw fixation of moderate and severe slipped capital femoral epiphyses may result in screw impingement upon the acetabulum and labrum. This is likely when the screw head on the anteroposterior view is seen to lie medial to the intertrochanteric line. Femoral artery pseudoaneurysm has been reported when the screws are left long (projecting far from the bone) to ease removal. Chondrolysis is associated with persistent penetration into the hip joint; both screws stop well short of the articular surface. Many in vitro studies of slip models have demonstrated increased strength of construct of two screws compared to one, although the clinical relevance can be questioned.

The radiographs show the screw heads firmly in the femoral head, with loss of fixation in the femoral neck. Sanders and associates reported a series of 7 such failures and hypothesized that acute-on-chronic slips may develop osteopenia of the femoral neck. All patients reported continued pain postoperatively rather than the relief typically seen following surgical stabilization of the epiphysis.

There is no radiographic evidence of osteonecrosis or chondrolysis.

 

Question 79-What is the most common physical examination finding in a patient with chronic painful spondylolysis?

 

1. Positive straight leg raise

2. Pain with forward flexion

3. Pain with lumbar extension

4. Absent tendo-Achilles reflex

 

DISCUSSION -Patients with spondylolysis typically demonstrate increased pain with lumbar extension, not with forward flexion. In the absence of a disk herniation, a straight leg raise test result should be negative. Pain with forward flexion is not common in spondylolysis, and without nerve root impingement there should be no loss of the tendo-Achilles reflex. PREFERRED RESPONSE: 3

 

Question 80-Plain radiographs do not provide an accurate assessment of bone mineral density (BMD) until what percentage of mineral has been lost?

1. 5%

2. 20%

3. 40%

4. 90%

 

DISC-Radiographic evidence of BMD loss is not apparent until 40% reduction. Osteopenia should not be ruled out based on an apparently normal mineralized bone. PREFERRED RESPONSE: 3

 

 

 

Question 81- are the anteroposterior radiograph of the spine and neck and the 3-dimensional reconstruction of the shoulders and spine of a 6-year-old girl. The child’s parent reported that she cannot keep up with her peers. She has difficulty with monkey bars and any activities that required her to raise her arms above her shoulder. Her neck is short, broad, and tilted. What is the diagnosis?

 

1. Facial scapular humeral dystrophy

2. Turner syndrome

3. Sprengel’s deformity

4. Congenital muscular torticollis

 

DISCUSSION

Sprengel’s deformity or congenital elevation of the scapula is the result of failure of caudal migration of the scapula. Approximately 30% of patients with this condition have an omovertebral bone as seen in the figures. In this patient the deformity is bilateral. Bilateral deformities occur in 10% to 30% of these cases. Cartilage, fibrous tissue or bone (the omovertebral bone) may attach the scapula to the cervical and thoracic spine. The latter limits shoulder abduction to 90 degrees. Cosmetically, the neck is broad and webbed similar to the condition seen in Turner syndrome. Sprengel’s deformity is found in 35% of patients with Klippel-Feil syndrome. Facial scapular humeral dystrophy does not entail an omoverterbral bone as noted on this patient’s CT scan. PREFERRED RESPONSE: 3

 

Question 82-show the radiograph and 3-dimensional (3-D) CT scans of a 2-year-old boy whose scoliosis has progressed 15 degrees during the past year. The child is clinically

healthy. He has been walking since 11 months of age. An MRI scan of the entire spine revealed no other anomalies. What additional study is indicated?

 

 

1. Renal ultrasound

2. Blood cultures

3. Flexion-extension cervical spine radiographs

4. Platelet count

 

DISCUSSION-Renal anomalies are found in as many as one-third of patients with congenital scoliosis, so a renal ultrasound should be obtained. There may be other anomalies, including cardiac. There are no other anomalies on MRI, so flexion-extension cervical spine radiographs are not

 

indicated. There is no associated marrow or platelet problem with hemivertebra. There is no indication for blood cultures because this is a noninfection disorder. The radiographs and 3-D CT scans show a hemivertebra scoliosis already beyond 45 degrees. Resection of the hemivertebra with stabilization is the indicated treatment.The scoliosis will get worse with observation and bracing. Fusion posteriorly can only minimally correct and not stop progression of the scoliosis. PREFERRED RESPONSE: 1

 

Question 83-At the time of arthroscopy, a 9-year-old boy was found to have a Watanabe type II discoid lateral meniscus. What is the most appropriate treatment?

1. Saucerization of the mensicus only

2. Saucerization and stabilization of the mensicus

3. Stabilization of the meniscus only

4. Complete menisectomy

 

DISCUSSION -The Watanabe type II mensicus should only require saucerization for treatment because it is not unstable.The Watanabe classification defines 3 types of discoid mensici. In type I (stable, complete), the blockshaped lateral meniscus covers the entire lateral tibial plateau, whereas in type II (stable, partial), the lateral meniscus covers ≤ 80% of the tibial plateau. Type III discoid menisci (unstable, ligament of Wrisberg) appear to be normal except for a thickened posterior horn, but they lack posterior meniscal attachments, including the meniscotibial (ie, coronary) ligament. The type III discoid meniscus is stabilized only by the meniscofemoral ligament of Wrisberg. This results in hypermobility of the lateral meniscus at the posterior horn, which pulls into the intercondylar notch with knee extension, resulting in snapping knee syndrome. Complete menisectomy should be avoided if possible. PREFERRED RESPONSE: 1

 

Question 84-are the anteroposterior and lateral radiographs of one of the feet of a 7-month-old infant who had bilateral flat feet on examination that exhibited 40-degree dorsiflexion and 10-degree plantar flexion at the ankles and no subtalar motion. What is the most appropriate next step in management?

 

 

1. Urgent surgical correction

2. Obtain a neurologic workup that includes neural axis imaging

3. Obtain an MRI scan of the foot

4. Advise the parents that flat feet are normal in infants and observation is recommended

 

DISCUSSION-Vertical tali have a high association with neural axis abnormalities and genetic neurologic syndromes, so a neurologic workup is the first step. The radiographs show rigid vertical tali that do not reduce in plantar flexion. Although the feet may correct with serial casting and less-invasive surgery may be required,this is less likely with rigid feet that do not reduce in plantar flexion. Flexible flat feet are common in infants and toddlers, but vertical tali are not. Vertical tali can be differentiated on examination by the lack of plantar flexion, subtalar motion, and a rocker-bottom appearance. An MRI scan will not provide additional information. PREFERRED RESPONSE: 2

 

 

 

Question 85-is the radiograph of a 3-year-old boy whose chief issue is knocked knees. His mother notes that she has a similar condition and required multiple surgeries as a child. She states that her son walks with an unsteady gait and is small for his age. He does not currently take any medications and is not under medical care for any disorders. What is the most appropriate next treatment step?

 

1. Recommend bilateral valgus-producing proximal femoral osteotomies to correct coxa vara

2. Recommend bilateral medial distal femoral and proximal tibial hemiepiphyseal arrests to

   correct genu valgum using guided growth

3. Obtain serum calcium, phosphorus, alkaline phosphatase, and vitamin D studies and refer the

   patient to an endocrinologist for evaluation

4. Refer the patient to a geneticist to evaluate him for skeletal dysplasia

 

DISCUSSION -The radiograph shows a patient with osteopenia; marked limb deformity, including bilateral coxa vara and bilateral genu valgum; and extreme physeal widening, which is pathonomonic for rickets. Although surgery to correct the limb deformities may be appropriate, a definitive

diagnosis first needs to be established, and, if possible, the patient needs to be treated medically. In cases in which limb realignment surgery has been performed without proper medial correction of the metabolic bone disease, the recurrence rate is high. Serum calcium, phosphorus, alkaline phosphatase, and vitamin D are appropriate screening studies for diagnosis of metabolic bone disease, and treatment is most commonly performed by an endocrinologist. A geneticist may play a role in establishing the cause of the disease, especially if there is a hereditary component, but this step should not delay the consultation with endocrinology. PREFERRED RESPONSE: 3

 

Question 86-Where is the physis with the highest growth rate (in mm per year) located?

1. Proximal humerus

2. Distal femur

3. Distal tibia

4. Distal radius

 

DISCUSSION -The distal femur averages 9 mm to 11 mm in growth per year, the proximal humerus 7 mm per year, the distal tibia 4 mm to 5 mm per year, and the distal radius 5 mm to 6 mm per year.

PREFERRED RESPONSE: 2

 

 

 

Question 87-is the pelvic radiograph of a newborn who had stiff bilateral talipes equinovarus and flexion contractures of both wrists with ulnar deviation. The Ortolani test result is negative in both hips. The newborn is to remain in the neonatal unit to address feeding issues for 1 to 2 weeks. What is the recommended course of action?

 

1. A Pavlik harness

2. A rigid abduction brace

3. CT scan of the pelvis

4. No treatment or imaging of the hips for several months

 

DISCUSSION -This child has a syndrome of multiple deformities, most likely amyoplasia. The right hip shows a teratologic dislocation with suggestion of pseudoacetabulum formation. It is appropriate to proceed with treatment of the foot and hand deformities and plan for open reduction of the hip at 6 months of age or older. Harness or brace treatment is unlikely to succeed in this high-riding teratologic dislocation. A

CT scan performed during the neonatal period would not be helpful. PREFERRED RESPONSE: 4

 

 

 

Question 88-is the anteroposterior elbow radiograph of an 8-month-old boy who had swelling and decreased use of his left elbow. His neurovascular examination is intact and he has no fever or chills. What is the most appropriate initial

treatment?

 

1. Obtain an MRI scan

2. Apply a long-arm splint

3. Closed reduction with pinning

4. Open reduction with pinning

 

DISCUSSION-This child has a Salter-Harris-type I fracture of the distal humerus. Standard treatment is closed reduction with or without internal fixation with pins. An MRI scan is typically not needed. Applying a splint without reduction will leave the fracture to heal in a suboptimal position. Open reduction is rarely necessary and would not be the most appropriate initial treatment. PREFERRED RESPONSE: 3

 

CLINICAL SITUATION FOR QUESTIONS 89 THROUGH 90

Figures 89a through 89c are the lateral radiograph and MRI scans of the right foot of a 15-year-old girl who was born with terminal amputations of her right middle and ring fingers, a cleft lip and palate, constriction bands at the left distal leg, and a right clubfoot for which she underwent surgical treatment at age 2. She has a chronic draining ulcer of her distal fifth metatarsal.

 

 

Question 89-What is the most likely cause of her foot deformity and the ulcer?

1. Pin tract infection from fixation after posterior medial release

2. Inadequate abductor hallucis release

3. Inadequate lateral release

4. Right peroneal neuropathy

 

Question 90-What is the most likely diagnosis for her condition?

1. Congenital amniotic band syndrome

2. Ehlers-Danlos syndrome

3. Fibular hemimelia

4. Arthrogryposis multiplex congenital

PREFERRED RESPONSE: 4

 

PREFERRED RESPONSE: 1

 

DISCUSSION FOR QUESTIONS 89 THROUGH 90

Streeter dysplasia or amniotic band syndrome is a congenital disorder caused by entrapment of fetal parts (usually a limb or digits) in fibrous amniotic bands in utero. It is associated with cleft lip or palate, terminal amputations, constriction bands, encephalocele, renal abnormalities, cardiac defects, hemihypertrophy, anterolateral bowing, tibial pseudarthrosis, and limb-length discrepancy. Clubfoot is seen in up to 25% of cases. Tight bands around the peroneal nerve that occur in 50% of children with

 

clubfeet can lead to nerve damage. This patient has chronic osteomyelitis resulting from pressure on the fifth metacarpal head in the presence of an insensate lateral foot. Traditional pinning in open clubfoot surgery does not breach the distal metatarsal. In an open procedure, releasing the abductor hallucis addresses forefoot abduction and is performed medially. The lateral release impacts the midfoot and hindfoot, but not lateral ray plantar flexion.

 

Question 91 -A 13-year-old boy who has a history of a pituitary adenoma has an unstable unilateral slipped capital femoral epiphysis. What is the indication for prophylactic pinning of the contralateral, unslipped side?

1. Patient gender

2. Patient age

3. Presentation with an unstable slipped epiphysis

4. Coexisting endocrine disorder

 

DISCUSSION-Endocrine disorders post the highest risk for bilateral involvement, and prophylactic pinning of the uninvolved side is most often recommended. Risk of contralateral slippage is highest in the youngest patients. In a study by Riad and associates, all girls younger than age 10 and all boys younger than age 12 presenting with a unilateral slipped capital femoral epiphysis subsequently developed a contralateral slip. Initial presentation of an unstable slip has not been shown to be an independent risk factor for later contralateral slippage. PREFERRED RESPONSE: 4

 

 

 

Question 92-is the CT scan of an 8-month-old girl with a left developmental hip dislocation who underwent a closed reduction with adductor longus tenotomy. An intraoperative arthrogram confirmed an adequate reduction and the child was placed in a hip spica cast. What is the most appropriate treatment?

 

1. Return to the operating room in 6 weeks for a cast change under anesthesia

2. Urgent repeat closed reduction and casting

3. Open reduction and femoral shortening osteotomy

4. Open reduction and Salter innominate osteotomy

 

 

 

DISCUSSION-The CT scan shows the left femoral head is subluxated posteriorly. Because reduction was adequate in the operating room, the best approach is to return to the operating room expeditiously, repeat the closed reduction, and recast in a better position. Open reduction could be considered if closed treatment is unsuccessful, but femoral shortening or innominate osteotomy should not be required at this age.PREFERRED RESPONSE: 2

 

Question 93-is the radiograph of 3½-year-old girl who was evaluated for a progressive increase in tibia vara and complains that her feet are turning in. What is the most appropriate course of action?

1. Bilateral tibia and fibular osteotomies

2. Valgus positioning knee-ankle-foot orthosis (KAFO)

3. Use of a Denis-Browne bar

4. Schedule a return visit in 4 months

 

DISCUSSION-The radiograph shows advanced changes in the medial tibial growth plates. The metaphyseal-diaphyseal angle is more than 20 degrees. With these advanced changes, an osteotomy is indicated.

Waiting will allow the problem to increase. Bracing (KAFO or night bar) has not been shown effective in advanced Blount disease.

PREFERRED RESPONSE: 1

Question 94-An 18-month-old girl sustained the isolated injury seen in Figure 94. She had pain and deformity at the fracture site and intact motor function and sensation distal to the injury. What is the most appropriate treatment?

 

1. Open reduction and internal fixation

2. Closed reduction and percutaneous pinning

3. Splinting and use of a sling for comfort

4. Application of a hanging-arm cast

 

DISCUSSION-The radiograph shows a left midshaft humerus fracture in a young, skeletally immature patient. The fracture does show significant angulation at age 18 months; however, even if the fracture heals with a malunion, excellent remodeling can be expected. As a result, none of the invasive treatment methods are necessary. Application of a hanging-arm cast likely would not provide any advantage in such a young patient who probably does not spend much time in a sitting or standing position. Any humeral shaft fracture in a nonambulatory patient should prompt consideration of nonaccidental trauma. PREFERRED RESPONSE: 3

 

 

 

Question 95-An 11-year-old boy with bipolar disorder fell from a tree and sustained an open fracture dislocation of the right ankle with extensive abrasions of the leg. Immediate irrigation, debridement, reduction, and provisional fixation with Kirschner wires was performed. Twenty-four hours later, the patient’s blood pressure is 190/100 mm Hg and pulse rate is 120. He has required only 1 dose of an oral analgesic for pain control. His foot and ankle are markedly swollen, but there is no pain on passive extension of the toes. The dorsalis pedis pulse cannot be palpated. What is the most appropriate next treatment step?

 

1. Remove the Kirschner wires and reposition the ankle

2. Measure foot compartment pressures

3. Order an echocardiogram

4. Order serum blood urea nitrogen and creatinine levels

 

DISCUSSION-The most common symptom of compartment syndrome in the extremities is intense pain. Compartment syndrome can be difficult to diagnose in children and patients who are comatose, nonverbal, and/or mentally compromised because they may not be able to properly express their level of pain. In compartment syndrome of the leg, pain on passive extension of the toes is the most frequent clinical diagnostic finding. However, in compartment syndrome of the foot, pain on passive extension of the toes may or may not be present. Swelling and absence of the dorsalis pedis pulse may be expected findings with extensive trauma to the foot, making the clinical diagnosis even more difficult. Repositioning the ankle will add to further swelling. The clinician must be alerted regarding elevations in blood pressure and pulse because such elevations may be the only manifestation of the deeper problem. The transient blood pressure elevation does not require cardiac screening with electrocardiogram or echocardiogram as in chronic hypertension. Kidney function testing is not necessary because the blood pressure elevation is not renal in origin. Compartment pressures should be measured immediately in the foot and will require anesthesia in the pediatric age group.

PREFERRED RESPONSE: 2

 

Question 96-What is a known risk factor for wound infection after spinal fusion for neuromuscular scoliosis?

1. Number of levels fused

2. Blood loss

3. Serum albumin level < 3.5 g/dL

4. Preoperative curve magnitude

 

DISCUSSION-The risk for wound infection after spinal fusion for neuromuscular scoliosis ranges from 4% to 14% and is higher than risk after spinal fusion in idiopathic scoliosis. A recent study of a database of 151 patients with neuromuscular scoliosis found the presence of ventriculoperitoneal

 

shunt to be associated with an increased risk for wound infection. Age, preoperative major curve magnitude, number of vertebral levels fused, length of surgery, blood loss, and transfusion requirements were not associated with increased risk.

A previous study found that poor nutritional status as measured by serum albumin < 3.5 g/dL (reference range, 3.5-5.0 g/dL) or lymphocytes < 1500 cells/μL (reference range, 1000-4800/μL) has been associated with increased postoperative wound infections.

PREFERRED RESPONSE: 3

 

Question 97 A 2-year-old boy was evaluated for toe-walking and clumsiness that were not present when he first walked at 1 year. His calves were noted to be quite large. He had a rigid equinus contracture of 10 degrees.When getting up from the floor, he rose to a tripod position and walked his hands up his legs until he was upright. Which of the following tests is most useful at this time?

 

1. Radiographs of his legs

2. Nerve conduction testing of his peripheral nerves

3. Creatine kinase blood level

4. MRI scan of his brain and spine

 

DISCUSSION-This history is classic for Duchenne muscular dystrophy, a condition present in approximately 1 in 3500 live male births. The disorder is caused by absent dystrophin in muscle; consequently, the creatine kinase levels at symptom onset are quite high (often > 25000 IU/L) (reference range, 55-365 IU/L). This is not a nerve disorder, so nerve tests, radiographs of the legs, and MRI scans of the neural axis will not yield a diagnosis.

PREFERRED RESPONSE: 3

 

Question 98 A dorsal bunion is a complication of clubfoot treatment. The pathophysiology is believed to be a muscle imbalance between

 

1. a weak anterior tibial muscle and strong peroneus longus muscle.

2. weak triceps and strong toe flexors.

3. strong triceps and weak toe flexors.

4. strong anterior tibial and strong toe flexors.

 

DISCUSSION-Two mechanisms can create a dorsal bunion in a treated clubfoot. In the clubfoot, strong toe flexors,flexor hallucis brevis, and abductor hallucis try to compensate for a weak triceps during push off. The classic mechanism is a strong anterior tibial dorsiflexing the first metatarsal, which is unopposed by weak peroneals. The other responses would not produce this deformity.

 

PREFERRED RESPONSE: 2

 

Question 99-A 3-year-old child with achondroplasia is hypotonic, and sleep studies reveal central apneic episodes. An initial workup should evaluate for what diagnosis?

 

1. Foramen magnum stenosis

2. C1-C2 instability

3. Adenoid and tonsillar hypertrophy

4. Tethered spinal cord

 

DISCUSSION-Foramen magnum stenosis can cause sudden death in young children with achondroplasia and must be ruled out with CT or MRI scans. C1-C2 instability does not occur in patients with achondroplasia.Lumbar stenosis and thoracolumbar kyphosis can be seen but are not life threatening and would not cause apnea or global hypotonia. Although many children with achondroplasia have adenoid and tonsillar hypertrophy, this condition causes obstructive rather than central sleep apnea and does not cause hypotonia. A tethered spinal cord is not particularly associated with achondroplasia and would not cause central apnea.

PREFERRED RESPONSE: 1

 

RESPONSES FOR QUESTIONS 100 THROUGH 104

1. Borrelia titer

2. Calcium, phosporus, alkaline phosphatase, vitamin D

3. Human leukocyte antigen (HLA)-B27

4. Complete blood count, erythrocyte sedimentation rate, C-reactive protein

5. Rheumatoid factor

6. Antinuclear antibody

7. Uric acid

 

The laboratory studies listed above are needed to diagnose the disorders listed below. Match theappropriate laboratory studies with each of these disorders.

 

Question 100-A 4-year-old girl has a 3-day history of progressive knee pain and the inability to bear weight. Her mother notes that she had a minor fall last week, but at that time her ambulation was not inhibited. Her physical examination reveals no knee effusion and tenderness in the distal femoral metaphysis. She has a lowgrade fever. Knee radiograph findings are normal.

PREFERRED RESPONSE: 4

Question 101-A 5-year-old boy has a 3-month history of pain in his left knee. His mother notes that he wakes each morning complaining of pain and stiffness. He has trouble walking to the breakfast table. His mother reports that the pain improves with ibuprofen, that he is able to go to school, and that he does not complain in the afternoons or evenings. His physical examination reveals mild swelling of the left knee compared to the right, but no effusion.

Range of motion of the knee is painless. He does not have any bony tenderness. Knee radiograph findings are normal.

PREFERRED RESPONSE: 4

Question 102-A 17-year-old boy has a 6-month history of low-back pain and stiffness. He localizes the pain to the lower lumbar paraspinous muscles. He has tried ibuprofen, experiencing some relief. His physical examination reveals pain in the low back with flexion, abduction, and external rotation of the hips. His radiographs reveal increased sclerosis adjacent to the sacroiliac joints.

PREFERRED RESPONSE: 3

Question 103-A 14-month-old African-American boy is evaluated for bowed legs. His mother notes no family history of limb deformities. He has been walking for 3 months. His mother notes that the bowing seems to be worsening. She reports that he has gained weight and met his motor milestones appropriately. He eats well but remains exclusively breastfed. His radiographs reveal osteopenia and widening of the physes at the distal femurs and proximal tibias.

PREFERRED RESPONSE: 2

 

Question 104-A 9-year-old boy returned from summer camp 4 months ago. He now has a 4-week history of right knee swelling. He denies significant pain, history of trauma, or any recent fevers or illness. His physical examination reveals a large knee joint effusion, painless range of motion of the knee, and stable knee ligaments.

PREFERRED RESPONSE: 1

DISCUSSION FOR QUESTIONS 100 THROUGH 104

The patient in Question 100 has a history most consistent with an infectious process such as osteomyelitis. Osteomyelitis most often presents acutely in children and is frequently associated with a precipitating minor trauma.

For the patient in Question 101 these findings are more consistent with juvenile idiopathic arthritis. Complete blood count, erythrocyte sedimentation rate, and C-reactive protein labs are indicated as initial testing in inflammatory conditions, including infection and juvenile idiopathic arthritis. Unlike adults who have rheumatoid arthritis, children with juvenile idiopathic arthritis are not likely to have a positive rheumatoid factor and testing does not need to be routinely ordered.

 

The patient in Question 102 has a history and examination suggestive of ankylosing spondylitis. HLA-B27 has 92% sensitivity and specificity for ankylosing spondylitis in European Americans and is

 

present in 90% of affected individuals. Alkaline phosphatase, along with serum calcium, phosphorus, and vitamin D, are essential to screen for metabolic bone disorders, including rickets.

The presentation of the child in Question 103 is most consistent with nutritional rickets. Although rare in the United States because multiple dietary supplements are easily accessible, nutritional rickets still occurs, most commonly in exclusively breastfed children (human breast milk does not provide significant vitamin D) who are dark skinned (vitamin D is synthesized in the skin from ultraviolet light exposure, and dark-skinned children absorb less UV light than light-skinned children).

The patient in Question 104 has a history and examination suggestive of Lyme arthritis. Lyme disease is caused by the bacterium borrelia burgdorferi, which is transferred to humans through deer tick bites, most often in the Northeastern United States. Lyme arthritis usually presents as a relatively painless knee effusion. A titer for this organism, which is initially an enzymelinked immunosorbent assay, is appropriate. Antinuclear antibodies are most commonly ordered when there is suspicion for systemic lupus erythematosis. Uric acid is most commonly ordered when there is suspicion for gouty arthritis.

 

Question 105-are the radiographs of a 13-year-old girl with right medial foot pain. The pain has been present for 3 months, is exacerbated by walking and running, and is relieved by rest. She had tried over-the-counter arch supports and nonsteroidal anti-inflammatory drugs for pain relief, but without success. Surgical treatment has been recommended. Which surgical procedure is most likely to relieve the patient’s symptoms?

 

 

1. Advancement of the posterior tibialis tendon to the inferior portion of the navicular

2. Splitting of the posterior tibialis tendon to excise the bony prominence

3. Performing a hindfoot osteotomy to correct pes planus

4. Performing osteosynthesis of the nonunited bone

 

DISCUSSION-Studies that have compared simple excision of the painful accessory navicular and prominent medial navicular with advancement of the posterior tibialis into the plantar midfoot (Kidner procedure) have shown no significant difference in outcomes. Simple excision, without correction of hindfoot valgus,has been shown to provide adequate pain relief in the majority of patients. Fixation of the nonunited accessory navicular to the proper navicular will not decrease the size of the painful medial prominence. PREFERRED RESPONSE: 2

 

Question 106-Which gene correlates with severity of disease in spinal muscular atrophy (SMA)?

1. Peripheral myelin protein 22 (PMP22)

2. Survival motor neuron I (SMN1)

3. Survival motor neuron II (SMN2)

4. Dystrophin

 

PREFERRED RESPONSE: 3-DISCUSSION-SMA is caused by a deficiency in SMN protein. Deficiency of SMN protein leads to progressive loss of anterior horn cells and progressive muscle weakness. The severity of disease is directly related to the amount of reduction in circulating levels of SMN proteins, which are encoded by 2 alleles of the SMN1 gene and multiple copies of the SMN2 genes on chromosome 5. Affected patients with all types of SMA will have functional loss of both SMN1 genes, so this does not differentiate disease severity. Disease severity depends on the number of functional copies of SMN2 that remain. Patients with SMA1 have only 1 functioning SMN2 gene, whereas the milder forms, SMA types 2 and 3, have multiple copies that

produce higher levels of SMN protein.

The other choices are not associated with spinal muscular atrophy.Defects in PMP22 are the cause of 70% to 80% of cases of Charcot-Marie-Tooth disease. Mutations in the dystrophin gene cause Duchenne muscular dystrophy.

 

Question 107-A 6-year-old girl is brought in for orthopaedic examination because she “walks funny” and occasionally trips. Her feet are normal in appearance. Internal rotation of her hips is 60 degrees and external rotation is 40 degrees bilaterally. The thigh-foot angle on the right is

-20 degrees, and +10 degrees on the left. What is the source of her gait abnormality?

 

1. Increased femoral anteversion

2. Increased femoral retroversion

3. Internal tibial torsion, right

4. External tibial torsion, left

 

DISCUSSION-Normal rotation in the hips should total approximately 100 degrees. Hip internal rotation is usually greater than external rotation, especially in girls. The thigh-foot angle is measured in a prone position and measures the angle the midaxis of the foot subtends with the midline of the thigh. The thigh-foot angle quantifies tibial rotation. Normal adult thigh-foot angle is approximately 10 to 15 degrees. This patient has increased internal rotation of the right tibia compared with the left; this is the likely cause of her gait problem.

 

PREFERRED RESPONSE: 3

 

Question 108-A 15-year-old boy with mild type I osteogenesis imperfecta (OI) has a midshaft radius/ulna fracture that is in bayonet apposition with loss of the radial bow and 40-degree apex volar and ulnar angulation. Closed reduction improves the angulation to 20 degrees; the bayonet apposition and loss of radial bow remains.His contralateral forearm has a normal appearance upon examination. What is the best treatment for this fracture?

 

1. Open reduction and plate fixation

2. Open reduction and intramedullary rod fixation with casting

3. Cast immobilization with expected remodeling of the fracture and near-full motion

4. Cast immobilization, accepting malunion and some dysfunction because surgical treatment has a high rate of nonunion in OI

 

DISCUSSION-Teenagers with displaced midshaft forearm fractures do not remodel fully if the angulation is beyond 10 degrees after reduction. Excellent outcomes have been shown with intramedullary rodding as well as plate fixation. In patients with bone fragility, plate fixation poses higher risks for fracture attributable to stress shielding. Load sharing with intramedullary rodding is preferred in surgical management of fractures whenever possible. This patient is 15 years old with unacceptable reduction, so remodeling of this fracture would not be expected with closed management. Patients with OI are not at higher risk for nonunion with surgery; there is no reason to withhold surgery for this patient.

 

PREFERRED RESPONSE: 2

 

 

 

Question 109-is the radiograph of an 11-year-old boy who felt a snap in his right hip while jumping hurdles during track practice yesterday. He complains of pain to his right groin region and is walking with a limp.What physical examination test will cause the patient to experience the most discomfort?

 

1. Resisted hip adduction

2. Resisted hip abduction

3. Resisted hip extension

4. Resisted knee extension

 

DISCUSSION-The radiograph shows an avulsion fracture from the right anterior inferior iliac spine. This is the site of origin of the rectus femoris tendon.

Contraction of the rectus femoris is most pronounced with extension of the knee. The adductor muscles, which would be tested with resisted hip adduction,

 

 

originate predominantly on the symphysis pubis. The abductors, which would be tested with resisted hip abduction,originate on the outer iliac crest. The hip extensors, which would be tested with resisted hip extension,originate on the posterior iliac crest. PREFERRED RESPONSE: 4-

 

Question 110-is the hips-to-ankles radiograph of a 3½-year-old girl being evaluated for bow legs. Her examination reveals her body mass index is 35, and she has a left knee varus alignment with a lateral thrust in gait. What is the most appropriate treatment?

 

1. Follow-up appointment in 6 months

2. Endocrine workup for rickets with calcium and vitamin D levels

3. Knee-ankle-foot orthosis brace to be worn during sports and follow-up in 6 months

4. Lateral hemiepiphysiodesis with guided growth technique

 

DISCUSSIO-This patient has left knee early-stage infantile Blount disease. After age 2, physiologic genu varum should be resolving. By age 3½ affected children have physiologic genu valgum, so observation is not appropriate because her medial physeal disturbance will progress to laterstage Blount disease with a bony bar. Infantile Blount disease is believed to be a mechanical disorder and does not need endocrine workup;also, the radiographs show no signs of rickets (physeal widening/cupping). Braces can be used, but they are associated with success rates of 50% to 70% if worn appropriately and are most effective for children younger than age 3.

To be effective, bracing is best worn full time, and has not been shown effective when worn fewer than 12 hours per day. Because recurrence rates after surgery are much higher in laterstage Blount disease and in children older than age 4, a hemiepiphysiodesis should be done now. Lateral hemiepiphysiodesis in Blount disease can be successful if done during the early stage and is minimally invasive. Corrective osteotomy also would be a reasonable choice for treatment.

PREFERRED RESPONSE: 4

 

Question 111-The Coleman block test is used to test for

 

1. flexibility of the forefoot.

2. flexibility of the hindfoot.

3. valgus deformity of the hindfoot.

4. tightness of tendo Achilles.

 

DISCUSSION -The Coleman block test is used to determine the flexibility of the hindfoot. When a block is placed under the lateral border of the foot, the medial column is unsupported. As a result, the first metatarsal drops off the side of the block. If the subtalar joint is flexible, there is no fixed varus

 

deformity of the hindfoot. The hindfoot will no longer be in varus from behind. The varus deformity of the hindfoot will be corrected. If there is no subtalar motion, the varus deformity remains fixed.

PREFERRED RESPONSE: 2

 

 

 

Question 112-is the photograph of a 2-month-old infant with a left leg deformity. The mother’s pregnancy and delivery were unremarkable, and the infant is otherwise healthy. What is the most appropriate course of action?

 

1. Osteotomy of the tibia and fibula

2. Clamshell knee-ankle-foot orthotic

3. Serial casts

4. Observation and a repeat visit in 4 months

 

DISCUSSION-The photograph shows posteromedial bowing of the tibia. The child should be followed for later limblength discrepancy, which may need treatment. Treatment with bracing or serial casts has not been shown to alter this condition. Surgery is not indicated in infancy because much of the deformity corrects with time. At a later age, treatment of a limb-length discrepancy or residual deformity can be addressed.

 

PREFERRED RESPONSE: 4

 

 

 

Question 113-are the radiographs of a 7-year-old girl who was evaluated for a visible elbow deformity by a foster parent. She thought the child fell, but her history was vague. On physical examination, a large prominence was seen over the posterolateral elbow, and the girl lacks the terminal 20 degrees of elbow extension. She has 75 degrees of elbow pronation and supination. She was nontender on examination. What is the most appropriate next treatment step?

 

1. Child abuse workup

2. Closed reduction

3. Open reduction with possible osteotomy

4. Observation

 

DISCUSSION-The most appropriate management of this condition is observation. The patient most likely has a congenital dislocation of the radial head, although this may also represent a posttraumatic deformity. The absence of findings on physical examination speaks against an acute injury.

The appearance of the radial head reveals the typical findings of a congenital dislocation, namely the convex appearance of the proximal radial articular surface. These children typically have very functional range of motion and do not require treatment unless they are symptomatic. There is nothing in this child’s history to suggest abuse.

PREFERRED RESPONSE: 4

 

 

 

Question 114-are the radiographs of a 5-year-old girl who fell from monkey bars. What is the first consideration regarding treatment for this injury?

 

 

 

1. Open reduction of the radiocapitellar joint

2. Reconstruction of the annular ligament

3. Closed reduction of the radial head dislocation and placement of a pin across the radiocapitellar joint

4. Accomplishing and maintaining a reduction of the ulnar fracture

 

DISCUSSION The radiographs show an ulnar shaft fracture with a radial head dislocation (Monteggia fracture). The ulnar shaft fracture requires reduction, either closed or open. Once the ulnar fracture has been reduced,usually the radiocapitallar joint will relocate with closed manipulation. In patients for whom the radiocapitallar joint does not relocate after ulnar reduction, or in patients with missed Monteggia injury,reduction of the radiocapitellar joint usually requires opening of the elbow capsule and reconstruction of the annular ligament. PREFERRED RESPONSE: 4-

 

CLINICAL SITUATION FOR QUESTIONS 115 THROUGH 117

show the radiographs of a child who sustained a fall from his bunk bed onto an outstretched arm.

 

 

Question 115-What is the best description of this fracture?

1. Gartland type I supracondylar humerus fracture

2. Gartland type II supracondylar humerus fracture

3. Gartland type III supracondylar humerus fracture

4. Flexion-type supracondylar humerus fracture

 

Question 116-What is the most appropriate initial treatment?

1. Closed reduction and casting

2. Open reduction and plating

3. Skeletal traction with an olecranon pin

4. Attempted closed reduction and percutaneous pinning

 

PREFERRED RESPONSE: 3

 

PREFERRED RESPONSE: 4

Question 117-The patient was unable to extend his wrist on preoperative examination. This was caused by injury to the

1. ulnar nerve.

2. radial nerve.

3. recurrent motor branch of the median nerve.

4. anterior interosseous branch of the median nerve. PREFERRED RESPONSE: 2

 

DISCUSSION FOR QUESTIONS 115 THROUGH 117

The radiographs show a Gartland type III supracondylar humerus fracture. Although multiple classification systems exist that describe supracondylar humerus fractures, Gartland’s classification is simple and widely used. Type I fractures are nondisplaced according to this classification. Type II

fractures are displaced with a variable amount of angulation, but the posterior cortex of the humerus is intact. Type III fractures are completely displaced with no cortical contact. In flexion-type supracondylar humerus fractures, the distal fragments are anterior to the humeral shaft. The most appropriate treatment method for this fracture is attempted closed reduction and pin fixation. Closed reduction and casting is inappropriate for a Gartland type III supracondylar humerus fracture.

Although open reduction may be required in some cases, most supracondylar humerus fractures, even those that are severely displaced, can be treated with closed reduction and percutaneous pin fixation (and this should be the initial approach).

 

 

Although olecranon traction is an option in managing these fractures, it involves repeated radiographs and prolonged hospitalization and is not widely used in North America. The preoperative examination is consistent with a radial nerve injury. Neuropraxias are common in supracondylar humerus fractures, with anterior interosseous nerve injury being the most common, followed by radial nerve. Ulnar nerve injuries occur in flexion-type supracondylar fractures and occasionally as the result of medial pin placement during surgery. The recurrent motor branch of the median nerve supplies the thenar muscles.

 

Question 118-is the radiograph of a 2-year-old boy who had an isolated injury. An immediate hip spica cast was chosen as the method of treatment. Which of the following techniques increases risk for compartment syndrome in the left leg following cast placement?

 

1. Using a single-leg spica instead of a double-leg spica

2. Wrapping the left short-leg portion of the cast first, then pulling traction through the fracture site

3. Placing the cast in an emergency department setting under sedation

4. Placing the cast within 24 hours of the injury

108 • American Academy of Orthopaedic Surgeons

 

DISCUSSION -Spica casting remains the standard of care for diaphyseal femur fractures in this age group. Spica casting has been shown effective when the cast is placed by experienced personnel while the patient is relaxed,whether in a setting using sedation or general

anesthesia. Immediate spica casting has not been associated with a higher rate of fracture shortening or other complications compared to traction and delayed casting.

To avoid the potential for compartment syndrome in the leg, the body and upper-leg portions of the cast should be placed first, followed by the lower-leg portion after the initial portion of the cast has been molded and the material has hardened. PREFERRED RESPONSE: 2

 

 

 

Question 119-are the anteroposterior (AP) and lateral radiographs of a 15-year-old boy who sustained an injury to his elbow after a fall while skateboarding. What structure is most at risk during the surgical repair of this lesion?

 

1. Median nerve

2. Ulnar nerve

3. Brachial artery

4. Ulnar collateral ligament

 

DISCUSSION-The structure most at risk at the time of surgical repair is the ulnar nerve. The lateral radiograph shows a bony structure in the joint space that represents the medial epicondyle, which is absent from its usual location on the

 

42

 

 

AP radiograph. The median nerve and the brachial artery should be well away from the surgical field. The ulnar collateral ligament is often attached directly to the medial epicondyle. PREFE RESP: 2

 

Question 120 A 12-year-old boy from Maine has an atraumatic knee effusion. He has no fever, mild tenderness, and lacks 10 degrees of flexion and extension. He continues to play basketball. He had flu-like symptoms 3 months ago. Radiographs and white blood cell count (WBC) findings are normal. His erythrocyte sedimentation rate is 53 mm/h (reference range, 0-20 mm/h) and C-reactive protein is 3.2 mg/L (reference range, 0.08-3.1 mg/L). The knee aspiration WBC count is 55000 leukocytes/mL (a synovial fluid count < 200 leukocytes/mL is within defined limits) with no organisms seen. What is the most appropriate initial treatment?

 

1. Administer Lyme titer and oral doxycycline

2. Operative lavage of the knee and start intravenous cephalosporin

3. Start nonsteroidal anti-inflammatory drugs (NSAIDs) and refer to rheumatology

4. Hospitalization for intravenous cephalosporin

 

DISCUSSION-This history suggests second-stage Lyme infection, which is common in the Northeastern United States. The condition often goes undiagnosed during the initial flu-like illness. Without treatment, Lyme disease progresses to the arthritic stage in 3 to 6 months. The Lyme antibody test should be ordered for this patient. Lyme is effectively treated with a 1-month course of doxycycline and does not require a surgical lavage. This history does not suggest acute septic arthritis or osteomyelitis because the boy can bear weight and has preserved range of motion with little pain and no fever despite his high inflammatory markers. Inflammatory monoarticular arthritis is less likely at this age, and Lyme disease needs to be excluded first in endemic areas. NSAIDs will not resolve Lyme disease without antibiotics. PREFERRED RESPONSE: 1

 

Question 121-are the anteroposterior (AP) and lateral radiographs of the right elbow of a 7-yearold boy who fell off the monkey bars onto his outstretched right hand. Immediate pain and swelling were noted around his elbow; there were no other injuries. His hand was neurovascularly intact. What is the best treatment for this fracture?

 

 

1. Closed reduction and casting in the emergency department

2. Closed reduction and percutaneous pinning of the fracture

3. Open reduction and plate fixation of the fracture in the operating room with early mobilization and no cast

4. Cast immobilization in the emergency department with the expectation that this injury will heal and remodel uneventfully

 

DISCUSSION-Displaced supracondylar fractures are best treated with surgical closed reduction and pin fixation followed by casting for 3 weeks. Closed reduction alone requires hyperflexion to hold the reduction and poses higher risk for compartment syndrome and Volkmann ischemia. Plate fixation in this age group is unnecessary considering robust periosteum and rapid healing with pin fixation.

Casting the fracture without reduction will lead to a malunion that does not usually remodel. The

 

radiographs reveal that the anterior humeral line does not intersect the capitellum in the lateral view, and the Baumann angle is disrupted in the AP view.

 

PREFERRED RESPONSE: 2

 

 

 

Question 122-is the radiograph of an 11-year-old gymnast who was evaluated for lateral foot pain that has been increasing during the past 6 months. She had 3 ankle sprains during the last 6 months. She was prescribed proprioceptive ankle exercises, orthotics, and a trial of a cast immobilization, but experienced no relief. She has foot pain with daily activity and is now unable to participate in gymnastics. What is the most appropriate course of action?

 

1. Discontinue gymnastics

2. Cast immobilization

3. Surgical treatment

4. Continued physical therapy

 

DISCUSSION-The radiograph shows a calcaneonavicular coalition. Surgical treatment of the coalition should result in symptom improvement. Nonsurgical treatment has been tried and failed. She has pain with daily activities, so discontinuing gymnastics is not likely to help. Cast treatment may provide temporary relief but does not provide relief once the cast is removed. Continued physical therapy is not likely to help because it has previously failed. PREFERRED RESPONSE: 3