Surgical hip dislocation (SHD) is a versatile approach used to address both intra-articular and extra-articular pathology around the hip joint. Developed and popularized by Ganz and colleagues, it allows anterior dislocation of the femoral head for direct visualization of the hip joint while preserving femoral head vascularity and minimizing trauma to the abductor musculature.1,2 In addition to direct visualization of intra-articular structures, it permits intraoperative observation of the pathomechanics of the hip as it is brought through range of motion, allowing the surgeon to address a wide variety of hip pathology in both pediatric and adult patients. Previously described indications for SHD include femoroacetabular impingement (FAI),3–6 deformity resulting from Legg-Calve-Perthes disease,7,8 slipped capital femoral epiphysis (SCFE),9–12 periarticular trauma,13,14 benign lesions of the hip joint,15–18 and osteochondral lesions.19–21 Important considerations to maximize patient outcomes when performing SHD include surgical approach, indications, techniques for addressing intra-articular and extra-articular pathology, and postoperative protocols.
The patient is positioned in the lateral decubitus position taking care to stabilize the pelvis perpendicular to the floor for proper intraoperative assessment of acetabular version. Padding is used to keep the operative leg parallel to the floor. Care is taken to ensure no pressure is on the peroneal, axillary, or ulnar nerves intraoperatively. The sterile field includes the inferior border of the rib cage superiorly and the posterior superior iliac spine posteriorly, extending distally to the operative leg, which is prepped free into the sterile field allowing intraoperative range of motion assessment. A straight incision is made centered over the anterior one third of the greater trochanter (Fig. 1). It extends distally beyond the vastus ridge and proximally to a point halfway between the iliac crest and the greater trochanter to give a final length of approximately 20 cm. Incisional length, particularly proximal to the greater trochanter is critical to minimize tension on soft-tissue structures and optimize visualization throughout the procedure. Proximally, we favor a Gibson modification of the Kocher-Langenbach, which develops the interval between the gluteus medius and gluteus maximus muscles, to minimize damage to the gluteus maximus.2 Distally, the iliotibial band is split in line with the femoral shaft. Bursal tissue from the lateral aspect of the greater trochanter and posterior border of the gluteus medius is gently split to visualize the posterior border of the gluteus medius at its insertion into the greater trochanter (Fig. 2). The hip is extended and internally rotated in preparation for trochanteric osteotomy, which also allows for better soft-tissue retraction of the posterior structures. We have found it beneficial to visualize the posterior border of the gluteus medius and visualize the location of the piriformis tendon before the trochanteric osteotomy. The fascia over the anterior border of the piriformis tendon is opened which allows for gentle distal retraction of the piriformis tendon. Retraction of the tendon will expose the posterior border of the gluteus minimus fascia. In patients with a more proximal trochanter such as Perthes, the inferior boarder of the gluteus minumis may be distal to the piriformis. Once the inferior border of the gluteus minimus fascia is opened, the dissection of the muscle from the capsule can be initiated in a superior/anterior direction. This will facilitate dissection once the trochanteric osteotomy is complete.
The trochanteric osteotomy should be performed parallel to the leg which is internally rotated to improve access for the osteotomy (Fig. 3). The proximal extent of the osteotomy is 1 fingerbreadth anterior to the posterior tip of the greater trochanter leaving some of the medius tendon on the stable trochanter. The distal extent of the osteotomy is the posterior border of the vastus lateralis insertion. The osteotomized fragment is approximately 15 cm in width and may need to be slightly smaller in younger hips. The gluteus medius, gluteus minimus, and vastus lateralis should remain on the trochanteric fragment. The piriformis and short external rotators remain on the femoral side of the osteotomy. The trochanteric osteotomy permits preservation of deep branches of the medial femoral circumflex artery, which provides blood supply to the femoral head. It courses posterior to the tendon of the obturator externus and becomes intracapsular where it provides branches to the retinacular vessels.22,23 Anastomosis with branches of the inferior gluteal artery running along the piriformis and short external rotators also provides perfusion to the femoral head.22,23 Preservation of the obturator externus, piriformis tendon, and short external rotators provides protection of femoral head vasculature.
The trochanteric fragment is mobilized anteriorly and the interval between the gluteus minimus, piriformis, and capsule is identified (Fig. 4). The gluteus minimus is gently lifted off the capsule superiorly and anteriorly (Fig. 5). Flexion and external rotation of the leg facilitates complete anterior exposure of the capsule. Distally, the vastus lateralis and intermedius are elevated off the femur. A Z-shaped capsulotomy is performed (Fig. 6). The transverse limb extends on the anterior femoral neck down to the intertrochanteric line, the superior limb follows the capsulolabral junction along the acetabulum as far as the piriformis tendon, and the inferior limb extends along the inferior femoral neck towards the lesser trochanter. With the hip joint exposed, the hip is taken through a full range of motion. Hip joint mechanics and impingement can be directly visualized as the reduced hip joint is brought through a range of motion intraoperatively.
The femoral head can now be dislocated anteriorly with gently flexion and external rotation as the leg is placed in a sterile leg bag. Curved scissors are necessary to release the ligamentum teres. The acetabulum and labrum can be visualized with flexion and gentle axial load on the leg, and retractors can be placed around the acetabulum for further visualization as needed. The femoral head can be inspected for cartilage integrity, deformity, and head-neck offset abnormalities. The retinacular vessels are visualized on the posterosuperior aspect of the femoral neck.
Experience with the extended retinacular flap, in which the retinacular vessels are left intact in a soft-tissue sleeve released from the femoral neck, becomes critical to preserve the blood supply to the femoral head when performing intra-articular osteotomies or procedures such as a modified Dunn.24 It is critical to safely perform this task and cadaveric dissection or mentorship on how to perform the extended retinacular flap is critical to decreasing the potential for avascular necrosis.
At the conclusion of the procedure, the capsule is closed under minimal tension to avoid injury to the retinacular vessels and the trochanteric fragment is fixed with 2 or three 3.5- or 4.5-mm cortical screws. The fascia of the gluteus maximus and medius are reapproximated proximally, the fascia lata is repaired distally, and a standard skin closure is performed. We do not routinely use a drain postoperatively, however, if excellent hemostasis is not achieved, a drain could be placed subfascially to prevent hematoma formation.
FAI results from abnormal contact between the proximal femur and the acetabular rim and/or pelvis with motion of the hip joint.6,25 This abnormal contact can result in pain, soft-tissue impingement, labral tears, chondral injury, and may lead to progressive degenerative arthritis of the hip joint.6,25 Symptomatic FAI primarily affects adolescents and younger adults engaged in activities that promote abnormal hip mechanics such as deep hip flexion or extreme hip range of motion. The diagnosis is being recognized increasingly in younger age groups, particularly those patients engaged in high-level competitive activity from a younger age.26–29 Between 2008 and 2011, children and adolescents between the ages of 10 and 19 represented over 30% of all patients undergoing surgery for FAI in a group of tertiary referral centers for hip preservation.30
Proper localization of impingement lesions and addressing concomitant pathology is critical to achieving success in treating patients with FAI. The most common forms of FAI are caused by abnormal contact between the femoral neck and the acetabular rim. Cam impingement results from contact between osseous abnormalities of the head-neck junction and the acetabular rim, and pincer impingement results from overcoverage of the acetabular rim contacting the femoral neck.6 Diagnosis of FAI can be challenging due to subtle symptoms or failure of recognition by inexperienced practioners, and many patients experience symptoms for extended periods of time before surgical intervention.6,31 Typical symptoms for FAI include activity-related anterior groin pain particularly with flexion and/or internal rotation activities. Physical examination reveals limitations in range of motion (ROM), particularly in internal rotation with the hip flexed, and provocation of pain with hip flexion and adduction of the internally rotated hip.6 Common radiographic abnormalities include deficient offset between the femoral head and neck, a nonspherical femoral head, and/or acetabular overcoverage.32 Advanced imaging such as magnetic resonance imaging may help visualize injury to cartilage and soft-tissue structures around the hip, whereas computed tomography scans may help identify subtle bony deformity contributing to impingement pathology.6,33
Extra-articular impingement is a less common source of hip pain in children and adolescents. This involves abnormal trochanteric-pelvic contact resulting in soft-tissue impingement and pain particular with activities involving extremes in ROM. Different types of trochanteric-pelvic impingement have been recognized. Contact can occur between the anterior facet of the trochanter or intertrochanteric ridge and the anterior rim of the acetabulum or anterior-inferior iliac spine.31 Contact may also occur between a prominent posterior trochanteric ridge and the ischium in flexion, abduction, and external rotation.31 This type of extra-articular impingement may be more common with excessive femoral anteversion due to a relative posterior position of the greater trochanter.31 Patients with extra-articular impingement may have anterior groin pain in provocative hip positions, but posterior or lateral pain with extremes of external rotation or abduction, respectively, may be present. Failure of pain relief with intra-articular injection may also be suggestive of extra-articular source of impingement.31
Treatment of FAI consists of both arthroscopic and SHD approaches. Increasing familiarity with hip arthroscopic approaches has led to an increasing proportion of FAI being treated arthroscopically.30 Our current indications for treatment of FAI with a SHD approach include suspected extra-articular impingement and lesions that are difficult to address arthroscopically such as posterior labral/rim lesions. Advantages of a SHD approach to FAI include the ability to visualize the hip joint through a full ROM, allowing all sources of impingement to be identified intraoperatively.31 Osteochondroplasty of the head-neck junction can be used to address cam-type deformities, and bony resection of the acetabular rim with repair of the labrum using suture anchors can address labral tears and pincer lesions.34 Trochanteric debridement at sites of extra-articular impingement seen with ROM of the hip intraoperatively can be performed to address this pathology. In certain cases, relative neck lengthening may be performed to fully address extra-articular impingement pathology, particularly in patients with relative coxa vara and short femoral necks. Visualization of the femoral head and acetabular cartilage allows treatment of osteochondral lesions.21 SHD remains a versatile surgical approach to address children and adolescents with FAI. Experience of the SHD approach with FAI may benefit the surgeon who is considering the approach with more complex pediatric deformities such as Perthes or SCFE.
Legg-Calve-Perthes is a childhood hip disorder that results from idiopathic avascular necrosis of the femoral head.35 Residual deformities of the proximal femur and acetabulum can result in pain, abductor weakness, early osteoarthritis, and FAI.8,36 Intra-articular sources of impingement can include head-neck offset abnormalities such as a typical cam lesion, severe femoral head deformity seen in coxa magna, and relative retroversion of the femoral head on the neck.8,36,37 Extra-articular sources of impingement include the greater and less trochanters resulting from trochanteric overgrowth or femoral neck shortening.8,38 Acetabular abnormalities including acetabular retroversion, dysplasia, and joint incongruity also frequently occur in symptomatic patients.8 Physical examination findings indicative of intra-articular and extra-articular impingement may be present along with abductor weakness.8,37 Radiographs may show coxa magna, coxa vara, shortened femoral neck, trochanteric overgrowth, acetabular retroversion, and acetabular dysplasia.8,37,39
Indications for SHD in Legg-Calve-Perthes include symptomatic intra-articular and extra-articular impingement. Osteochondroplasty of the head-neck junction for cam impingement, femoral head reduction osteoplasty for coxa magna, and femoral osteotomy for femoral retroversion can be used to address intra-articular impingement.8,37 Relative femoral neck lengthening can address greater trochanteric impingement and overgrowth8,38,39 (Figs. 7A, B). This involves creating an extended retinacular artery flap, which separates the lateral retinacular vessels from the proximal aspect of the greater trochanter and femoral neck.24 The residual greater trochanter can be debrided safely and the osteotomized portion of the trochanter can be translated distally to improve abductor length and reduce impingement with less risk to the blood supply of the femoral head.8,28,39 Concomitant femoral or acetabular osteotomies can be performed to address residual deformities.8
SCFE is a common hip disorder in adolescents.40 Treatment goals include stabilization of the epiphysis while minimizing the risk of avascular necrosis.11 Traditional treatment involving in situ pinning has provided good results, however, there is increasing evidence of persistent FAI and chondral injury in these patients over time even with less severe slips.41,42 The indications for SHD in SCFE continue to evolve.
For previously treated SCFE with residual FAI, SHD can be used successfully with or without an intertrochanteric osteotomy for osteochondroplasty, labral repair, and treatment of chondral injury.43,44 In cases of unstable or more severe slips, Ganz and colleagues developed a modified Dunn technique, which allows realignment of the epiphysis on the femoral neck, avoiding the postslip deformity and progressive damage to the hip joint.45 A modified Dunn involves creating an extended lateral retinacular flap to protect the blood supply to the femoral head and mobilizing the slipped epiphysis with its blood supply still attached under direct visualization to avoid tension on the vessels.11,45 After excision of the physis and callus, the epiphysis is realigned over the femoral neck and pinned into place45 (Fig. 8). Intraoperative monitoring of femoral head perfusion is possible with the use of laser Doppler flowmetry or a sterile arterial line catheter.11,46 Techniques to reduce the risk of avascular necrosis (AVN) include the extended retinacular flap, slight shortening of the metaphysis to avoid tension on the retinacular flap, and ensuring that the soft-tissue flap is not kinked (which may occur with too much neck shortening) or entrapped between the metaphysis and epiphysis. Advantages of this approach include correction of the deformity at its origin, which will prevent postslip impingement and may decrease the risk of future chondral degenerative changes; however, the procedure has a steep learning curve, which carries the risk of AVN.9,10,12 Given the challenges of this approach and its evolving indications, further study is necessary to evaluate its learning curve and results in high-volume centers.
BENIGN PERIARTICULAR LESIONS AND TRAUMA
Two less common indications for SHD include excision of benign lesions around the hip joint and periarticular trauma. The use of SHD has been described for excision of osteochondromas, synovial chondromatosis, and pigmented villonodular synovitis.15–18 The extensile exposure of both intra-articular and extra-articular structures allows removal of any impinging bony lesions, synovectomy, and treatment of osteochondral defects.15–18,20 In cases of periarticular trauma, SHD has been described for treatment of osteochondral lesions, open reduction and internal fixation of femoral head fractures, and assistance with articular surface visualization in the management of acetabular fractures.14,21 The use of SHD for these less common indications must be evaluated on a case-by-case basis and surgeon comfort with the procedure.
Our postoperative protocols include partial weight-bearing on the operative extremity for 4 to 6 weeks. Continuous passive motion is used for the first 2 weeks from 0 to 30 degrees. No active abduction versus gravity is allowed to protect the trochanteric osteotomy fixation. Patients are counseled to avoid sitting for prolonged periods of time at 90 degrees. For younger patients, mechanical DVT prophylaxis is used exclusively. For young adults and older patients, pharmacologic prophylaxis with aspirin twice per day is used. Other pharmacologic prophylaxis may be used in patients at risk for DVT. Physical therapy is begun at 6 to 12 weeks depending on the procedures performed.
Overall, clinical outcomes show that SHD is a safe procedure that demonstrates improved range of motion and clinical outcomes in FAI, Legg-Calve-Perthes, and SCFE when performed in high-volume centers.5,8,10,12,34,47 The most common complications in a multicenter study of SHD including all current indications were low-grade heterotopic ossification (4.2%) and trochanteric nonunion (1.8%).48 Males were at greater risk of heterotopic ossification, and no cases required further treatment.48 All cases of trochanteric nonunion healed after revision of the fixation.48 There were no cases of AVN or femoral neck fracture in this large cohort that did not include osteotomies.48 In treatment of SCFE using a modified Dunn, the reported rates of AVN vary depending on the series from 0% to 26%.9,10,12 Surgeon experience and baseline AVN rates with unstable SCFE make it difficult to evaluate the true AVN rates with this procedure as it use expands across centers. Continued follow-up studies on clinical outcomes and complication rates for SHD must continue as its indications broaden and an increased number of surgeons begin to perform the procedure.
SHD is a versatile, extensile exposure that allows treatment of both intra-articular and extra-articular pathology of the hip. Surgeon experience and volume are critical to minimize complications and optimize outcomes. Having a mentor with experience and cadaveric dissection will facilitate the surgeon’s learning curve. Having familiarity with the approach before more complex deformities such as SCFE and Perthes is recommended. Learning to perform a careful extended retinacular flap is critical to decrease the complications of complex pediatric deformity. Indications are evolving as understanding of hip pathology improves, and involvement of a multidisciplinary team is important to select patients appropriately.
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8. Albers CE, Steppacher SD, Ganz R, et al.. Joint-preserving surgery improves pain, range of motion, and abductor strength after Legg-Calvé-Perthes disease. Clin Orthop Relat Res. 2012;470:2450–2461.
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25. Leunig M, Beck M, Woo A, et al.. Acetabular rim degeneration: a constant finding in the aged hip. Clin Orthop Relat Res. 2003;413:201–207.
26. Agricola R, Bessems JH, Ginai AZ, et al.. The development of Cam-type deformity in adolescent and young male soccer players. Am J Sports Med. 2012;40:1099–1106.
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in youth ice hockey players. Am J Sports Med. 2013;41:1357–1362.
29. Siebenrock KA, Behning A, Mamisch TC, et al.. Growth plate alteration precedes cam-type deformity in elite basketball players. Clin Orthop Relat Res. 2013;471:1084–1091.
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: early mechanical damage to the acetabular cartilage by a prominent femoral metaphysis. Acta Orthop Scand. 2000;71:370–375.
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. J Pediatr Orthop. 2010;30:26–30.
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: surgical hip dislocation
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46. Nötzli HP, Siebenrock KA, Hempfing A, et al.. Perfusion of the femoral head during surgical dislocation of the hip. Monitoring by laser Doppler flowmetry. J Bone Joint Surg Br. 2002;84:300–304.
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: part II. Midterm results of surgical treatment. Clin Orthop Relat Res. 2004;418:67–73.
48. Sink EL, Beaulé PE, Sucato D, et al.. Multicenter study of complications following surgical dislocation of the hip. J Bone Joint Surg Am. 2011;93:1132–1136.