Wrist CASES 3

CASE                               21                               

Following an intense game of football, a player is brought to you with complaints of pain over the ulnar side of his wrist. X-rays reveal a transverse pisiform fracture. What is your treatment plan?

1. Surgery; as these fractures do not heal

2. Short arm splint

3. Steroid injection

4. Ace wrap

5. Do nothing as these fractures heal uneventfully

 

Discussion

The correct answer is (B). A period of splinting in a short arm splint is a reasonable initial line of treatment for a pisiform fracture.

The pisiform is classified as what type of bone?

1. Atavistic

2. Membranous

3. Rudimentary

4. Intercalated

5. Sesamoid

 

Discussion

The correct answer is (E).

 

The pisiform is located within which tendon?

1. ECU

2. FCU

3. FDP of the small finger

4. FDS of the small finger

5. Palmaris brevis

 

Discussion

The correct answer is (B).

 

Your patient fails to respond to an initial period of splinting and you decide on a surgical approach. What is the preferred surgical procedure in this case?

1. ORIF with k wires

2. ORIF with a headless screw

3. Excision of the pisiform

4. Intraosseous wiring

5. Injection of platelet-rich plasma

 

Discussion

The correct answer is (C). Excision of the pisiform is a frequently used procedure for chronic, intractable pain associated with pisiform fractures. It generally does not cause any measurable functional deficit.

 

Objectives: Did you learn...?

 

Treat pisiform fractures?

 

Describe the osteology of the pisiform?

 

Identify anatomy and surgical treatment of pisiform fractures?

 

CASE                               22                               

An elderly lady complains of pain at the base of both of her thumbs. She mentions that it is progressive and does not recollect any trauma to the region. An x-ray is shown (Fig. 3–17). What do you suspect?

1. 1st carpometacarpal (CMC) arthritis

2. Bennett’s fracture

3. Pathological fracture of the base of the trapezium

4. Avascular necrosis of the trapezium

5. Secondaries in the trapezium

 

 

 

Figure 3–17 (©) Sunil Thirkannad and Christine M. Kleinert.

 

Discussion

The correct answer is (A).

 

She says that she has been suffering for too long and would like to proceed with surgery. Which of the following procedures has demonstrated the best longterm results?

1. Trapezium excision alone

2. Trapeziectomy followed by interposition arthroplasty using a free tendon graft anchovy

3. Trapeziectomy followed by a sling arthroplasty using the FCR

4. Trapeziectomy followed by a sling arthroplasty using the ECRL

5. No difference has been demonstrated between any of the above procedures

 

Discussion

The correct answer is (E). Long-term studies have failed to demonstrate any appreciable differences between simple trapeziectomy versus any of the other procedures requiring some form of interposition or arthroplasty by ligament reconstruction. However, individual surgeons continue to perform any of the above procedures or their numerous variations based on personal preference.

You elect to perform a trapeziectomy and sling arthroplasty using part of the FCR tendon. Which structure is at direct risk of injury during dissection for this procedure?

1. Sensory branch of the radial nerve

2. Median nerve

3. Palmar cutaneous branch of the median nerve

4. Radial artery

5. All of the above

 

Discussion

The correct answer is (E). The sensory branches of the radial nerve pass very closely to the site of incision over the 1st CMC joint. The median nerve as well as the palmar cutaneous branch of the median nerve are closely related to the FCR tendon and are at risk if an open dissection technique is used to harvest the tendon. The radial artery crosses the anatomical snuff box and is at risk during deep dissection around the trapezium.

During surgery, you discover that the FCR tendon has undergone attritional rupture and is unavailable for ligament reconstruction. Which alternate tendon has been used in these circumstances to recreate a similar biomechanical construct?

1. EPL

2. EPB

3. ECRL

4. ECRB

5. Palmaris longus

 

Discussion

The correct answer is (C). The ECRL tendon also inserts to the base of the second metacarpal like the FCR. The difference lies in the fact that the FCR is volar while the ECRL is dorsal. Use of the ECRL to create a sling between the 1st and 2nd metacarpals recreates a similar biomechanical structure as would using the FCR. However, care must be taken to ensure that the ECRL tendon graft is passed deep to the radial artery prior to being delivered into the CMC joint area. Failing to do so and passing the tendon graft superficial to the radial artery can create a pincer effect on the artery and potentially lead to its occlusion and thrombosis.

 

Objectives: Did you learn...?

 

 

Identify CMC arthritis from radiographs? Treat CMC arthritis?

 

 

Name the structures at risk during surgical treatment? Identify the ligaments used for reconstruction?

 

CASE                               23                               

A 30-year-old lady in her third trimester of pregnancy presents with pain at the base of her right thumb. She denies history of any trauma and mentions that it is particularly painful while turning on her car keys. What would you consider most likely to be the cause of her pain?

1. Wartenburg’s syndrome

2. DeQuervain’s tenosynovitis

3. 1st CMC arthritis

4. Radial artery thrombosis in the anatomical snuff box

5. Radio-scaphoid arthritis

 

Discussion

The correct answer is (B). DeQuervain’s tenosynovitis is known to be aggravated or

sometimes even precipitated by pregnancy. While all the other conditions listed above can also potentially cause pain at the base of the thumb, they are significantly less common given the age and circumstances of this particular patient.

Which extensor compartment is affected in DeQuervain’s tenosynovitis?

1. 1st

2. 1st and 2nd

3. 2nd

4. 1st and 3rd

5. 2nd and 3rd

 

Discussion

The correct answer is (A).

 

What tendons are affected by DeQuervain’s tenosynovitis?

1. ECRL and ECRB

2. APL and EPB

3. EPB and EPL

4. APL and APB

5. APB and EPL

 

Discussion

The correct answer is (B).

 

Following a period of conservative treatment, you decide to proceed with surgery. Intraoperatively, you open the compartment and discover two tendons. Traction on both of these tendons produces abduction of the thumb metacarpal. You do not see any other tendons in this area. What is the most likely scenario?

1. Nothing unusual. You have successfully decompressed the affected compartment

2. The EPB is most likely missing in this patient

3. The EPB has most likely ruptured in this patient

4. The EPB is most likely located within a separate subcompartment

5. The patient has a combined extensor pollicis longus et brevis

 

Discussion

The correct answer is (D). While responses A, B, C and are all possible, the

commonest variation seen is the presence of a separate subcompartment. In fact, studies have shown that the presence of a separate subcompartment for the EPB may actually be more common than the presence of a single compartment for the APL and EPB.

 

Objectives: Did you learn...?

 

 

Identify the compartment affected by DeQuervains tenosynovitis? Treat DeQuervains tenosynovitis?

 

Identify variatons of the first compartment anatomy?

 

CASE                               24                               

A 23-year-old auto mechanic presents with several months of an achy pain over the dorsum of his wrist. An x-ray is shown (Fig. 3–18). What is your diagnosis?

1. VISI deformity

2. DISI deformity

3. Osteosarcoma

4. Subluxation of the CMC joint

5. Carpal boss

 

 

 

Figure 3–18 (©) Sunil Thirkannad and Christine M. Kleinert.

Discussion

The correct answer is (E).

 

What further investigation would you recommend in this case?

1. MRI without contrast

2. MRI with contrast

3. Thin slice CT scans

4. Radioisotope bone scan

5. None of the above

 

Discussion

The correct answer is (E).

Plain radiography is sufficient to make a diagnosis of a carpal boss.

 

What is a carpal boss?

1. Synonym for osteochondroma

2. Osteophytes arising from the 2nd or 3rd CMC joint

3. A malunited avulsed fracture of the ECRL tendon

4. Ectopic calcium deposits secondary to hyperparathyroidism

5. None of the above

 

Discussion

The correct answer is (B).

 

Which structures are at greater risk of rupture during surgery for a carpal boss?

1. EPL at Lister’s tubercle

2. The Juncturae tendinum between the EDC tendons

3. ECRB tendon

4. ECU tendon

5. Extensor digitorum quinti tendon

 

Discussion

The correct answer is (C). The ECRB tendon inserts to the base of the 3rd metacarpal which is the most common site of a carpal boss. Often this tendon needs to be sharply dissected away from the metacarpal to enable excision of the osteophytes. Consequently, it is at a greater risk for potential rupture during

surgery.

 

Objectives: Did you learn...?

 

 

Identify a carpal boss? Diagnose a carpal boss?

 

Identify the structures at risk during treatment of carpal boss?

 

CASE                               25                               

Following a fall on his outstretched hand, a 27-year-old teacher presents with mild pain in his wrist. You obtain an x-ray which is shown (Fig. 3–19). What is your diagnosis?

1. Carpal coalition

2. Perilunate dislocation

3. DISI

4. VISI

5. None of the above

 

 

 

Figure 3–19 (©) Sunil Thirkannad and Christine M. Kleinert.

 

Discussion

The correct answer is (A).

 

People of which ethnicity have a high incidence of lunotriquetral coalition?

1. White Caucasians

2. Native Americans

3. Chinese Americans

4. African Americans

5. Ashkenazi Jews

 

Discussion

The correct answer is (D).

 

Which classification system is commonly used for lunotriquetral coalitions?

1. Steindler classification

2. Minnaar classification

3. Swanson classification

4. American Wrist Society classification

5. Kleinert classification

 

Discussion

The correct answer is (B).

 

Which of the following radiological features is considered to be typical of Minnaar type 1 coalition?

1. Fluted champagne glass appearance

2. Notched appearance

3. Complete coalition

4. Triangle sign

5. Signet Ring sign

 

Discussion

The correct answer is (A). Minnaar Type 1 refers to a fibrous/cartilaginous type of coalition. In these cases, the lunotriquetral joint is seen as a narrowed space, often slightly wider distally than proximally, giving the appearance of a fluted champagne glass.

 

Objectives: Did you learn...?

 

 

Identify carpal coalition from the imaging? Manage carpal coalition?

 

Classify Carpal coalition?

 

CASE                               26                               

An active, 19-year-old gymnast complains of ulnar-sided wrist pain. She has already obtained an MRI scan which reveals ECU tendinitis. Where does this tendon principally insert?

1. Base of 4th metacarpal

2. Hamate

3. Dorsal ridge of triquetrum

4. Blends with the 4th dorsal interosseous aponeurosis

5. Base of 5th metacarpal

 

Discussion

The correct answer is (E).

 

What is the anatomical peculiarity of the ECU?

1. It receives dual nerve supply

2. It is the only extensor which also provides attachment to a lumbrical muscle

3. It contains a sesamoid bone

4. It is enclosed by a separate subsheath

5. It is the only extensor not contained within a compartment

 

Discussion

The correct answer is (D).

 

Which extensor compartment does the ECU pass through?

1. 4th

2. 5th

3. 6th

4. 7th

5. None of the above

 

Discussion

The correct answer is (C).

 

In addition to acting as a wrist extensor, what other role has been attributed to

the ECU?

1. It stabilizes the ulnar head preventing dorsal subluxation

2. It enables opposition of the 5th metacarpal

3. It is responsible for rotatory movements at the capitate-hamate joint

4. It augments the dorsal radio-triquetral bundle

5. It provides attachment to the TFCC

 

Discussion

The correct answer is (A). The ECU tendon, along with its subsheath, acts as a dorsal stabilizer of the ulnar head. It passes through a groove on the dorsoulnar aspect of the head of the ulna and is known to play a role in preventing its dorsal subluxation.

 

Objectives: Did you learn...?

 

 

Recognize the anatomy of the ECU? Identify the role of the ECU?

 

CASE                               27                               

Several years after sustaining an injury to his wrist, a firefighter presents to your clinic with chronic wrist pain. What does his x-ray (Fig. 3–20) reveal?

1. DISI

2. Carpal coalition

3. Ulnar translation

4. VISI

5. None of the above

 

 

Figure 3–20 (©) Sunil Thirkannad and Christine M. Kleinert.

 

Discussion

The correct answer is (C).

 

How much does the width of the lunate need to be off the radius for a diagnosis of ulnar translation to be made?

1. >30%

2. >50%

3. >25%

4. Is determined by the displacement of the scaphoid in the scaphoid fossa

5. None of the above

 

Discussion

The correct answer is (B).

 

Ulnar translation of the lunate serves as a relative contraindication for which

procedure?

1. Total wrist fusion

2. Total wrist arthroplasty

3. Four-corner fusion

4. Proximal row carpectomy

5. Fascia lata interposition arthroplasty

 

Discussion

The correct answer is (D). Ulnar translation of the lunate indicates weakness of the radio-scaphocapitate ligament. This serves as a relative contraindication for proximal row carpectomy as the risk of the capitate also translating ulnar wards is high, leading to an unstable wrist.

Which of the following surgical procedures is indicated in correcting ulnar translation of the carpus?

1. Radioscapholunate fusion

2. Radial styloidectomy

3. Arthroscopic debridement of the TFCC

4. Ulnar shortening

5. Scaphoid excision and four-corner fusion

 

Discussion

The correct answer is (A).

 

Objectives: Did you learn...?

 

Identify criteria of ulnar translation?

 

 

Identify contraindications of proximal row carpectomy? Surgically manage ulnar translation of the carpus?

 

CASE                               28                               

A young lady presents with chronic pain in her wrist which she describes as a deep boring type. An x-ray (Fig. 3–21) is shown. She denies any history of trauma in the past. What do you suspect?

1. Kienbock’s disease

2. Osteoid osteoma

3. Preiser’s disease

4. Osteopetrosis

5. Hyperparathyroidism

 

 

 

Figure 3–21 (©) Sunil Thirkannad and Christine M. Kleinert.

 

Discussion

The correct answer is (C).

 

What investigation would help confirm your diagnosis?

1. CT scan

2. Arthroscopy

3. Arthrogram

4. MRI with contrast

5. Angiogram

 

Discussion

The correct answer is (D).

Preiser’s disease is a spontaneous avascular necrosis of the scaphoid. MRI with gadolinium is the most sensitive modality to confirm this condition.

What is your preferred treatment for this condition?

1. Scaphoid excision and four-corner fusion

2. Botox injection

3. Daily application of nitroglycerine paste over the scaphoid

4. Proximal row carpectomy

5. Vascularized bone graft to the scaphoid

 

Discussion

The correct answer is (E).

 

Which pedicle is commonly used to revascularize the scaphoid?

1. 2–3 ICSRA

2. 1–2 ICSRA

3. 1st ECA

4. 2nd ECA

5. Dorsal carpal arch

 

Discussion

The correct answer is (B).

 

Objectives: Did you learn...?

 

Diagnose Preiser’s disease?

 

 

Identify signs and symptoms of Preiser’s disease? Operatively manage Preiser’s disease?

 

CASE                               29                               

A 19-year-old girl presents to you with a painful wrist. As part of your investigations, you ask for x-rays of the wrist. Your radio technician is inexperienced and unsure of how to obtain proper views. How would you position the patient to obtain a PA view?

1. Shoulder adducted, elbow flexed to 90 degrees with forearm pronated and hand placed flat on the film

2. Shoulder abducted to 90 degrees, elbow flexed to 90 degrees with forearm neutral and hand placed flat on the film

3. Shoulder adducted, elbow flexed to 90 degrees with forearm supinated and hand placed flat on the film

4. Shoulder abducted to 90 degrees, elbow flexed to 90 degrees with forearm supinated and hand placed flat on the film

5. Shoulder abducted to 90 degrees, elbow flexed to 90 degrees with forearm pronated and hand placed flat on the film

Discussion

The correct answer is (B).

 

How would you position your patient for a lateral view of the wrist?

1. Shoulder adducted, elbow flexed to 90 degrees with forearm neutral and ulnar border of hand placed on the film

2. Shoulder abducted to 90 degrees, elbow flexed to 90 degrees with forearm neutral and ulnar border of hand placed on the film

3. Shoulder adducted, elbow flexed to 90 degrees with forearm supinated and ulnar border of hand placed on the film

4. Shoulder abducted to 90 degrees, elbow flexed to 90 degrees with forearm supinated and ulnar border of hand placed on the film

5. Shoulder abducted to 90 degrees, elbow flexed to 90 degrees with forearm pronated and ulnar border of hand placed on the film

Discussion

The correct answer is (A).

 

Whose lines are used to determine proper intercarpal alignment within the proximal and distal carpal rows?

1. Shenton’s lines

2. Kleinert’s lines

3. Zaidemberg’s lines

4. Barton’s lines

5. Gilula’s lines

Discussion

The correct answer is (E). Gilula described three smooth lines drawn on a PA view. The first corresponds to the proximal articular surfaces of the scaphoid, lunate, and triquetrum. The second line is along the distal articular surfaces of the scaphoid, lunate, and triquetrum while the third line is along the proximal articular surfaces of the capitates and hamate.

How is the carpal height ratio determined on an x-ray of the wrist?

1. Ratio of the height of the lunate to the height of the capitate

2. Ratio of the height of the carpus to the height of the third metacarpal

3. Ratio of the height of the capitate to the height of the carpus

4. Both B and C

5. Ratio of the height of the lunate to the longitudinal axis of the scaphoid

 

Discussion

The correct answer is (D). The carpal height ratio is classically described as the ratio of the height of the carpus to the height of the third metacarpal. However, as most wrist x-rays do not include the entire third metacarpal, the ratio of the height of the capitate to the height of the carpus is accepted as an alternate method of assessing the carpal height ratio.

 

Objectives: Did you learn...?

 

 

How to properly position the upper extremity for a PA view of the wrist? Describe the significance of Gilula’s Lines?

 

How to determine the carpal height ratio on x-ray?

 

CASE                               30                               

You are invited by your medical school to speak to first year medical students about the anatomy of the wrist. One of the students asks you about the most likely role of the terminal branches of the posterior interosseous nerve. What is your response?

1. They carry cutaneous nerves to the dorsum of the wrist

2. They supply proprioceptive branches to the wrist joint

3. They carry motor nerves to the 3rd and 4th dorsal interossei

4. They carry sympathetic fibers to the dorsal carpal arch artery

5. They carry sudomotor nerves to the dorsum of the wrist

 

Discussion

The correct answer is (B). The posterior interosseous nerve ends in a pseudoganglion over the dorsum of the carpus. Small terminal branches pass from this to the wrist joint. The general consensus is that these fibers are mainly proprioceptive in nature and may also carry deep pain sensations. Resection of the posterior interosseous nerve over the wrist joint is often carried out as a remedy for intractable wrist pain.

Another student asks you to name the weak spot over the carpus that has been implicated in lunate and perilunate dislocations. What would you say?

1. Parona’s space

2. Midpalmar space

3. Poisuelli’s space

4. Poirier’s space

5. Carpal recess

 

Discussion

The correct answer is (D). The space of Poirier is a bare area over the volar aspect of the lunate that is not covered by any extrinsic or intrinsic carpal ligament. While controversy exists about the exact nomenclature of the ligaments that border this space, it is generally agreed that this is the weak spot through which volar luxations of the lunate occur.

Your old anatomy teacher tells you that he thinks there is a muscle that has a dual nerve supply in the hand but is unable to recollect its name. What would you say to him?

1. There is no muscle with a dual nerve supply in the hand

2. Flexor pollicis brevis

3. Second lumbrical

4. Palmaris brevis

5. Abductor digitorum minimus

Discussion

The correct answer is (B). The FPB has two bellies and receives supply from both the median nerve and deep branch of the ulnar nerve.

Finally, a bright, eager student asks you what the nerve of Henle is. What is your response?

1. It is a branch of the ulnar nerve that carries sympathetic fibers

2. It is an anomalous connection between the median and ulnar nerves in the wrist

3. It is a branch from the posterior interosseous nerve that provides proprioception to the carpus

4. It is an anomalous branch from the median nerve that can sometimes supply the palmaris brevis muscle

5. It is the nerve supplying the anomalous extensor digitorum manus brevis muscle

 

Discussion

The correct answer is (A).

 

Objectives: Did you learn...?

 

 

Discuss the role of the terminal branches of the posterior interosseous nerve? Identify the significance of Poirier’s space?

 

 

Identify the innervation of the FPB? Describe the nerve of Henle?