Conservative Hip Surgery Case Title: Periacetabular Osteotomy

Demographics

1.  

   Age: 28 Sex: Female BMI: 29

    

2. Relevant Past Medical History

    

   Principal pathologies: None

   Previous surgical procedures: None

   Medication: None

   History of presenting complaint: A 28-year-old female presented with right hip pain for over 1 year. The pain was primarily located in the groin which was constant and worse at the end of the day. She had tried physical therapy and had a corticosteroid injection in her right hip that relieved 100% of her pain but only lasted approximately 25 min. She also complained of occasional left hip pain.

3. Clinical Examination

    

   Symptoms: Right hip anterior groin pain with milder left hip groin pain

   Range of motion: Extension-flexion: 0–125; internal-external rotation: 40–60; abduction-adduction: 45–30

   Specific tests: Positive Stinchfield test, positive flexion-adduction-internal rotation test

   Main disability: Anterior groin pain and difficulty with ambulating and physical activity

   Neurovascular evaluation: Normal motor and sensory exams in the sciatic, femoral, and obturator nerves. Normal pulses in the posterior tibial and dorsalis pedis arteries

    

4. Preoperative Radiological Assessment/Imaging (Figs. 1.26, 1.27, and 1.28)

    

    

    

   Fig. 1.26 Anteroposterior X-ray view of the pelvis demonstrates bilateral hip dysplasia. Note that the bilateral femoral head undercoverages laterally. The right hip lateral center-edge angle (CEA) measured 15-degrees, and the Tonnis angle was 17-degrees. The left hip lateral CEA and the Tonnis angle were 18 and 15 degrees, respectively

    

    

    

    

    

   Fig. 1.27 Cross-table lateral X-ray view of the left hip demonstrates anteversion of the left acetabulum

    

    

    

    

   Fig. 1.28 False profile X-ray image of the left hip shows anterior undercoverage of the femoral head. The anterior CEA was 17- degrees. The right hip also had similar anterior undercoverage with a similar anterior CEA

    

5. Preoperative Planning

    

   Diagnosis: Bilateral symptomatic mild hip dysplasia (Figs. 1.26, 1.27, and 1.28).

   Possible treatment options: Continued nonoperative treatment, probable eventual total hip arthroplasty.

   Chosen treatment method: Staged bilateral periacetabular osteotomies (PAOs). The right side was treated initially with a PAO and an open arthrotomy with anterior inferior iliac spine trimming. The left hip was then treated three years later with a combined hip arthroscopy to address a labral tear as well as acetabular and femoral chondroplasties and a PAO for correction of the dysplasia.

   Selection of implants if applicable and rational: Large fragment 4.5 mm screws.

   Expected difficulties: (1) Sufficient osteotomy to be able to completely mobilize the acetabular fragment in all planes. (2) Adequate deformity correction to address the anterior and lateral femoral head undercoverage. (3) Avoid acetabular overcorrection which would lead to anterior femoroacetabular impingement, and decrease the patient’s flexion and internal rotation.

   Strategies to overcome difficulties: (1) Ensure completely osteotomies of the ischium, pubis, and ilium. The acetabular fragment should be easily mobilized in all planes without much force. The most common location that requires extra attention is the junction of the ischial osteotomy with the posterior column. (2) The deformity correction is performed with a Schanz pin in the iliac portion of the acetabular fragment. A bone hook is also used at the pubic osteotomy to ensure complete release of the pubic segment without any tethering and allows the fragment to be rotated to increase lateral coverage without inadvertently causing retroversion. The fragment is then repositioned with slight extension, internal rotation, and medialization. Of note, it is important to understand that this deformity correction is different as compared to reverse PAOs for acetabular retroversion. The fragment is then temporarily stabilized with 3.2 mm Steinmann pins, and the correction is assessed carefully with intraoperative fluoroscopy. It is important to obtain an adequate anteroposterior view and modified false profile view. (3) Assess the patient’s preoperative range of motion

    

   (ROM) in flexion and internal rotation while the patient is under anesthesia and compare it to the patient’s flexion and internal rotation following deformity correction and temporary fragment stabilization.

    

6. Surgical Note

    

   Patient’s position: Supine.

   Type of anesthesia: General anesthetic as well as an epidural for postoperative pain management.

   Surgical approach: Anterior approach with a curved skin incision centered just lateral to the anterior superior iliac spine (ASIS). The fascia over the tensor fascia lata (TFL) muscle is then seen and incised. The TFL is retracted laterally, and the sartorius is retracted medially. The direct and indirect heads of the rectus femoris are identified and protected. The anterior pelvic brim is then exposed by incising the fascia over the external oblique muscle just lateral to the iliac crest and elevating the iliacus muscle subperiosteally. The sartorius tendon is tagged with a suture and taken off the ASIS. Dissection is further developed along the anterior pelvic brim and superior pubic ramus. The dissection along the superior pubic ramus is advanced just medial to the iliopectineal eminence to ensure an adequate superior pubic ramus osteotomy. During this portion of the exposure, it is important to flex the ipsilateral hip and knee to protect the femoral nerve. Once the approach is complete, attention is then directed to completion of the osteotomies in a reproducible and sequential fashion.

   Main steps:

    

   1. Surgical exposure.

   2. Identification of the ischial osteotomy which is found by following the medial edge of the rectus femoris tendon and the inferomedial capsule with large Metzenbaum scissors and a Cobb elevator. Fluoroscopic guidance is also utilized to ensure proper osteotomy placement within the infracotyloid groove at the superior edge of the ischium. This incomplete osteotomy is aimed toward the middle of the ischial spine.

   3. Superior pubic osteotomy which is done under direct visualization. The osteotomy site is

      exposed with a sharp narrow Homan that is impacted into the superior pubic ramus just medial to the osteotomy site and blunt Homans placed around the superior and inferior aspects of the superior pubic ramus, respectively. This osteotomy is angled away from the hip joint starting medially to the pectineal eminence.

   4. Iliac osteotomy which is usually started at the inferior edge of the ASIS and ends 1 cm from the pelvic brim. A large Homan is first placed into the greater sciatic notch to expose the inner table of the ilium, and fluoroscopy is used to identify the medial end point for the iliac osteotomy which also acts as a target. This site is marked with cautery and a burr. The osteotomy is then completed with an oscillating saw.

   5. Posterior column osteotomy which is done with a combination of direct visualization and fluoroscopy. This osteotomy which is done with osteotome(s) is started at the medial edge of the iliac osteotomy and directed distally to join with the ischial cut. Fluoroscopy is used to ensure proper direction along the retroacetabular space. This helps to avoid osteotome penetration into the hip joint or completely osteotomizing the posterior column. The osteotomy usually propagates distally. As the osteotomy is nearing completion, a large laminar spreader can be placed into the iliac osteotomy to help with mobilization of the acetabular segment.

   6. Placement of a Schanz pin into the superior aspect of the acetabular fragment in the ilium.

   7. Determination of complete mobility of the fragment by moving the Schanz pin and fragment rotationally in a clockwise or counterclockwise fashion.

   8. Reorientation of the fragment followed by temporary stabilization, fluoroscopic assessment of the correction, and assessment of the patient’s hip range of motion, particularly in flexion and internal rotation.

   9. Definitive fixation of the fragment.

    

   Reconstruction techniques: Reorientation of the fragment to increase femoral head lateral and anterior acetabular coverage and to medialize the hip center of rotation. The fragment is stabilized with two to three 4.5 mm screws that are directed from superior to inferior from the iliac crest,

    

   across the iliac osteotomy site and into the fragment (Figs. 1.29 and 1.30).

    

7. Intraoperative Challenges

    

   Challenges and solutions: Challenge: full mobilization of the acetabular fragment; solution: ensure complete osteotomies of the ischium, superior pubic ramus, ilium, and posterior column. This may require several passes with the osteotome(s). It is also beneficial to have several different types of osteotomes available that are different sizes and have varying amounts curvature that can help with osteotomy direction, especially with the posterior column osteotomy which is difficult in obese patients due to the large abdomen. Challenge: reorientation of the fragment to provide increased coverage anteriorly and laterally as well as medialization of the center of rotation; solution: make sure that the fragment is internally rotated, slightly extended, and medialized. This will likely require a bone hook into the superior pubic ramus osteotomy so that it is displaced and not hinged.

   Unanticipated problems and solution: Problem: overcorrection that would cause anterior femoroacetabular impingement; solution: verify hip flexion and internal rotation perioperatively while the patient is under anesthesia and compare the patient’s hip flexion and internal rotation after fragment reorientation. Overcorrection would be indicated by a significant change and limitation to flexion and internal rotation, which would necessitate an adjustment to the acetabular fragment’s position. If the fragment is adequately positioned, it may be necessary to perform an arthrotomy and osteochondroplasty of the head-neck junction if needed.

   Thorough description of decision making, including the reason for the final decision: Hip dysplasia can cause hip pain and is a known cause of early hip osteoarthritis. Given this patient’s significant bilateral hip pain, labral tears, and hip dysplasia, the decision was made to undergo bilateral PAOs with the goals of improving the patient’s symptoms, hip biomechanics, and longevity. The right hip, which was addressed first, was also treated with an open arthrotomy at the same time of the PAO. Three years later, a combined hip arthroscopy and PAO was performed to

   address the labral tear and dysplasia of the left hip. That is our treatment of choice today.

    

8. Postoperative Radiographs

   (Figs. 1.29 and 1.30)

    

    

    

    

   Fig. 1.29 Anteroposterior X-ray demonstrates bilateral periacetabular osteotomies, each stabilized with two

   4.5 mm screws. Note increased lateral coverage of both femoral heads and medialization of both hip centers. Lack of anterior overcoverage was verified intraoperatively with ROM examination

    

    

    

    

   Fig. 1.30 False profile view of the left hip which demonstrates increased anterior coverage of the femoral head. The false profile view of the right hip demonstrated a similar correction

    

9. Postoperative Management

    

   Chemoprophylaxis and anticoagulant treatment period: Sequential compression devices while in the hospital and compression stockings worn for six weeks. Aspirin 325 mg twice daily is also given for six weeks.

   Gait/limb loading until full loading: Toe-touch weight bearing for four weeks with a maximum of 30 pounds on the operative limb. The patient was able to progress to weight bearing as tolerated four weeks postoperatively. She also used a continuous passive motion device for four weeks for the left hip from 0 to 90 degrees of knee flexion for 4–6 h per day because of the arthroscopic labral repair.

    

10. Follow-Up and Complications

     

    None

     

11. Discussion

     

    Advantages of the applied method: The periacetabular osteotomy has several advantages. First off, it is joint preserving and may extend or obviate the need for a total hip arthroplasty. The procedure allows for complete control of the fragment which provides a large degree of deformity correction in multiple directions. The posterior column also remains intact which provides acetabular stability and allows for partial weight bearing postoperatively. Furthermore, an anterior arthrotomy can be performed through the same approach at the same time to address any intra-articular pathology, such as a labral tear or a CAM lesion.

    Disadvantages of the method: The PAO is a large surgical procedure that requires extensive rehabilitation, including a 4-week period of toe-touch weight bearing. It usually leads to injury to the lateral femoral cutaneous nerve causing a decreased sensation and occasionally can cause dysesthetic pain along the lateral aspect of the thigh. Symptomatic hardware is also not uncommon and often requires a second procedure for removal of hardware.

    Alternative evidence-based techniques for the case: Total hip arthroplasty. No role of hip arthroscopy alone.

    Why is the chosen technique better for this case? It is a hip preservation technique and allows for multidirectional reorientation of the acetabulum.

    Indications and contraindications for your technique: Indications: hip dysplasia and isolated acetabular retroversion that causes impingement [36]. Contraindications, young pediatric patients with an open triradiate cartilage, patients with asymptomatic mild hip dysplasia or asymptomatic retroversion, and patients with radiographic evidence of osteoarthritis.

    Learning curve and how to manage complications: The learning curve for performing a PAO is high, especially with patient selection. The most technically demanding portions of the surgery include fully mobilizing the acetabular fragment and performing an adequate deformity correction while avoiding under-correction or overcorrection. Proper patient selection and carefully determining the patient’s preoperative radiographic undercoverage and ROM can help to avoid these pitfalls. Complications include superficial wound infection, wound dehiscence, deep infection, failed hardware, osteotomy delayed union or nonunion, intra-articular acetabular fracture, neurologic injury to the lateral femoral cutaneous nerve or sciatic or femoral nerve, and heterotopic ossification [37]. Recently, obesity was found to be a major independent risk factor for increased complication for a PAO [38]. Wound complications are typically treated with oral or intravenous antibiotics with or without an irrigation and debridement procedure. Established symptomatic aseptic nonunions are addressed with surgery for stabilization and bone grafting, but that is rarely required. Neurologic injuries, which are rare, are usually treated with observation as they are commonly neurapraxias. Symptomatic heterotopic ossification can be treated with heterotopic bone excision followed by prophylaxis with either indomethacin or radiation. Hardware failure may require revision of the fixation or removal of the hardware.

    Level of evidence concerning the superiority

    of this method against others: Level IV [39].