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Combined Surgical Dislocation and Proximal FemoralOsteotomy for Correction of SCFE-InducedFemoroacetabular ImpingementMichael P. McClincy, MD, and Patrick P. Bosch, MD

1048-6666/13/doi:http://dx.do

n’s Hospital ofter, Pittsburgh,reprint requeburgh of UPM, Pittsburgh, PA

Slipped capital femoral epiphysis (SCFE) is a common adolescent hip disorder. Its cause is notfully understood but is likelymultifactorial involving both biological and biomechanical factors.The currentmanagement of SCFE is focused on stabilizing the proximal femoral epiphysis as ittranslates along the physis. In significant deformities, the epiphysis remains in a posterior,inferior, and retroverted position after fixation. Some patients undergo osseous remodeling toresolve the deformity, butmost will have residual deformity into adulthood. Residual deformityof the proximal femur frequently leads to a cam-type femoroacetabular impingement, whichcan expedite the process of degenerative osteoarthritis. Many approaches to surgicallyaddress post-SCFE femoroacetabular impingement have been described, including femoralneck osteoplasties to remove the impinging lesion andproximal femoral osteotomies to realignthe femoral head within the acetabulum. Below, we describe a combined approach involvingsurgical hip dislocationwith openosteoplasty followedbyan intertrochanteric osteotomy. Thisoperation addresses both aspects of the proximal femoral deformity associatedwith SCFE andis an optimal approach for correcting severe deformities.Oper Tech Orthop 23:140-145 C 2013 Elsevier Inc. All rights reserved.

KEYWORDS slipped capital femoral epiphysis, surgical hip dislocation, femoroacetabularimpingement

Slipped capital femoral epiphysis (SCFE) is the mostcommon adolescent hip disorder, with an estimated

incidence of 10.8 cases per 100,000 children.1,2 Thegrowing epidemic of childhood obesity means the rate ofSCFE is likely to increase in the near future.3 Althoughcurrent literature endorses a multitude of factors involvinganatomy, endocrinology, and biomechanics as playingsignificant contributory roles in the development of thecondition, a definitive etiology has yet to be established.4,5

As the cause of SCFE is not fully understood, no treatmentsare available to prevent or reverse its clinical course.Practitioners, therefore, are left to manage the disorder withthe intent to minimize its clinical effect. Although the initialmanagement of SCFE is controversial, especially withunstable slips, the majority of patients are managed byin situ fixation of the femoral epiphysis to the femoral

$-see front matter & 2013 Elsevier Inc. All rights reserved.i.org/10.1053/j.oto.2013.08.002

Pittsburgh of UPMC, University of Pittsburgh MedicalPA.sts to Patrick P. Bosch, MD, Children’s Hospital ofC, University of Pittsburgh Medical Center, 4401 Penn15224. E-mail: patrick.bosch@chp.edu

neck.6 In performing an in situ fixation, a formal reductionis generally avoided because of concerns for possiblecompromise of the blood supply to the femoral head andresultant osteonecrosis.7 The proximal femoral anatomy israrely restored with in situ fixation, leaving a potential fordeformity-related complications.As the epiphysis “slides” along the proximal physis, itmost

commonly migrates into a position of posteroinferior trans-lation and retroversion of the femoral head in relation to theneck. This produces distortions in the sagittal, coronal, andaxial planes, creating a complex 3-dimensional deformity. Insitu fixation relies on remodeling of the proximal femur overtime to return to a more anatomically accurate geometry.Some remodeling is predictable and occurs in over 50% ofcases.8 However in the absence of sufficient bony remodelingor in cases of severe slip displacement at the time of initialintervention, residual prominence of the anterolateral fem-oral neck can develop a clinically significant cam-typefemoroacetabular impingement (FAI) and damage the chon-drolabral complex of the acetabulum.9-11 Rab described2 mechanisms of FAI-induced chondrolabral injury, impac-tion, and inclusion, both occurring secondary to the SCFE

Figure 1 Lateral-abduction radiograph of a 14-year-old female withpersistent hip pain. She has had previous flexion (Imhauser type)osteotomy to treat anterior impingement from previous SCFE. Thiscase demonstrates potential need for additional osteoplasty.

Combined surgical dislocation and proximal femoral osteotomy 141

deformity.12 In impaction, labral damage results fromaberrant contact of the anterolateral proximal femoralmetaphysis with the acetabular rim. In inclusion, a meta-physeal prominence caused by a low-grade SCFE or osseousremodeling may lie within the joint resulting in chondralwear through outside-in abrasion.Post-SCFE osteoarthritis is a significant concern, with

prior studies showing that all degrees of SCFE deformities(mild 15%-25%, severe 60%-100%) have significant ratesof osteoarthritis that are seen as early as the fourth and fifthdecades of life.13-15 In the absence of other early osteo-arthritis risk factors, several studies have concluded thatresidual FAI is the likely cause of early hip joint degener-ation. In an effort to delay or even prevent the progressionof hip joint degeneration, surgical interventions to restore amore anatomically accurate femoral head or neck complexhave been described.16-20 Surgical techniques previouslydescribed include both osteoplasties and osteotomies ofthe proximal femur. Femoral neck osteoplasties, per-formed through either open or arthroscopic approaches,serve to address the cam-type impinging lesion of theproximal femur by reshaping the femoral head-neckjunction.18,21 Osteotomies in the subcapital, intertrochan-teric, or subtrochanteric regions have been described as ameans of reorienting the femoral head within the acetab-ulum to minimize the effects of impingement and returnthe thickest portion of articular cartilage into the weight-bearing zone.19,20,22

Arthroscopic osteoplasty of the femoral neck has theadvantages of being a limited approach to the hip; however,it is a technically demanding procedure and the amount offemoral neck that is visualized makes it best suited for mildcases. The metaphyseal deformity in more significant casesfrequently prevents adequate visualization and subsequentremoval of the impinging lesion.23 Some authors have added amini–open approach to the proximal femur to improve poorarthroscopic visualization.21 No studies are available for long-term outcomes of arthroscopic osteoplasty, but short-termfollow-up cohorts show modest improvement in range-of-motion and hip scoring systems in patients with mild post-SCFE deformities.16,18

Open osteoplasty became a potential intervention in 2001after Ganz introduced a means of safe surgical hip disloca-tion.24 Its utility in the treatment of SCFE-induced FAI havebeen shown by multiple authors. At an average of 42 monthsfollow-up, Rebello et al17 showed an improvement inWesternOntario andMcMaster Universities Osteoarthritis Index scoresfor pain, function, and stiffness following open osteoplasty incases involving moderate levels of proximal femur deformity.Spencer et al25 also showed promising results over a shorterfollow-up period (12 months) with improvements in WesternOntario and McMaster Universities Osteoarthritis Index painand function scores. Multiple studies have noted surgicaldislocation with osteoplasty to be a relatively safe procedurewith no reported cases of postoperative osteonecrosis.17,25,26

In cases of severe deformity, the role of osteoplasty has beenquestioned owing to concerns of overresection leading tofemoral neck fractures.27

Proximal femoral osteotomy has also been a well-described intervention for SCFE-induced FAI. Osteotomieshave been described at the femoral neck,28 intertrochan-teric,29 and subtrochanteric regions.20 In general, osteoto-mies performed closer to the focus of deformity providebetter correction but also carry a higher risk of femoral headosteonecrosis. Each intervention aims to reverse the flexion,varus and external rotation deformities of the proximalfemur. Overall, the Imhauser intertrochanteric osteotomyhas become the most commonly used due to its relativebalance of deformity correction and complication rate.30 TheImhauser osteotomy performed acutely in SCFE manage-ment has been evaluated in 2 notable long-term studies, eachwith follow-up greater than 20 years. Clinical success (lack ofosteoarthritis symptoms) was demonstrated in 55%-77% ofcases and radiographic success (lack of osteoarthritis changeson radiographs) in 55%-67% of cases. Significant improve-ments were noted in patients with all degrees of deformity.Osteonecrosis was found to have a rate of 2%-5% in thesestudies. Saisu et al8 recently published results on 32 patientstreated with late intertrochanteric osteotomies for SCFE-induced FAI at an average of 5-month follow-up, finding nocases of osteonecrosis and 75% of patients with minimalradiographic evidence of arthrosis.In the cases of severe post-SCFE FAI, many authors have

now begun utilizing a combined approach to deformitycorrection (Fig. 1) including a surgical dislocation andosteoplasty with a proximal osteotomy.17,19 In these severecases, the osteoplasty alone provides insufficient decompres-sion and it is felt that the minor increase in femoral headosteonecrosis from an osteotomy is justified because of theenhanced deformity correction. Our institution has alsoexperienced success with the combined proximal femoralosteoplasty and intertrochanteric osteotomy through a surgicaldislocation in the treatment of severe post-SCFE femoroace-tabular impingement cases. Below, we present the operativetechniques that we employ in addressing these cases.

Figure 2 Intraoperative photograph of femoral head exposed bysurgical dislocation. This patient is 8 months following in situ fixationof a stable SCFE. (Color version of the figure is available online.)

M.P. McClincy, P.P. Bosch142

TechniqueThe patient is positioned in the lateral decubitus position andstabilized with positioning posts or a beanbag. Additionalpadding includes axillary roll and foam padding for the greatertrochanter andfibular head of the down leg. A pillow above thedown leg can pad the operative leg, which we will also oftensupport on a padded, sterile Mayo stand used to adjust therelative abduction of the extremity.The skin incision is made longitudinally along the proximal

femur, centered in the anterior-posterior plane over the greatertrochanter. The distal extension of the incisionwill be longer toaccommodate the proximal femoral exposure for the fixationof the osteotomy. In the lateral decubitus position, thesignificant subcutaneous layer often present in this patientpopulation will fall to the side. The fascia lata is incised with ascalpel and subsequently split proximally and distally withMayo scissor.The surgical dislocation and head-neck morphology are

addressed first. The surgical dislocation aspect of this operationhas been expertly presented in a previous publication.24 Inbrief, the posterior aspect of the greater trochanter is visualizedby internal rotation of the hip. The trochanter is osteotomizedfrom the proximal tip of the trochanteric to just inferior to thevastus lateralis ridge. This effectively mobilizes the majority ofthe gluteus medius and vastus lateralis anteriorly with thetrochanteric fragment. Proximally, the interval between thepiriformis and the posterior aspect of the gluteus minumus isexploited with progressive external rotation of the hip, and thehip capsule is exposed. One must not injure the lateralretinacular vessels located posterior to the piriformis tendon.The dissection is carried anteriorly and distally to include therelease of the vastus intermedius off the capsule. The anteriormuscle sling with the trochanter is retracted with a bluntHohmann on the calcar region of the femur and a sharpHohmann impacted on the outer pelvic wall superolateral tothe acetabulum. A capsulotomy in line with the femoral neck isextended anterior inferiorly and posterior medial in a z-type

Figure 3 Schematic representation of operative technique forosteotomy. (A) The greater trochanter is provisionally fixedwithplate are inserted. (B) The osteotomy is performed and the princluding fixation of the greater trochanter. (C) The proximfemoral shaft.

fashion. Awareness of the posterior-lateral retinacular vesselson the femoral neck and the labrum along the acetabular rimguide the entry into the joint.Visualization of the femoral head can now be accomplished

with positioning of the leg in flexion and external rotation. Theleg can be placed into a sterile bag but an arthroplasty-styledrape with a sterile pouch is our preference. For head-neckrecontouring in the subacute and chronic phases, jointsubluxation is often adequate. However, if further examinationand treatment of acetabular damage is desired, a full surgicaldislocation can be performed (Fig. 2). The ability to relocate thejoint and take the hip through a range of motion duringsequential bony resections is a significant advantage of theopen osteoplasty technique. In addition to improving thehead-neck morphology, the posterior slip of the femoralepiphysis should also be assessed. By extending the hip untilthe epiphysis is optimally reduced, the amount of flexion for

fixation of the greater trochanter and intertrochanterica Kwire and the guide pins for a proximal femoral lockingoximal locking plate is affixed to the proximal segment,al segment is “flexed” and the plate is reduced to the

Figure 4 Intraoperative photograph of the reduction of the proximalsegment of femur and locking plate with the femoral shaft. The asterix(*) marks the apex posterior angulation of the proximal femoralsegment. (Color version of the figure is available online.)

Combined surgical dislocation and proximal femoral osteotomy 143

the intertrochanteric osteotomy can be planned. This shouldallow the surgeon to replace the thickest portion of femoralhead cartilage into the main weight-bearing area. When theintra-articular osteoplasty is satisfactory, the joint is reducedand the capsule repaired.

Figure 5 Case example of surgical correction achievedwith comb(A and B) Anterior-posterior and abduction-lateral radiographs ofor stable SCFE. She continues to have low-grade hip painwith awith hip flexion and internal rotation. (C and D) Anterior-poste4 months after surgical dislocation osteoplasty and proximal fe

The osteotomy is usually started just inferior to the level ofthe initial trochanteric osteotomy, and exits slightly proximalto the lesser trochanter. To expose this portion of the femur:the vastus lateralis should be incised 1-1.5 cm posterior toanterior from the inferior aspect of the trochanter, preservingthe anterior half of its insertion. Distal dissection of the vastuslateralis anteriorly is needed to allow for plate fixation to thefemoral shaft.The greater trochanter can be repaired before performing

the osteotomy with the use of 3.5-mm screws from thegreater trochanter piece into the proximal femur. However,we have found fixation to be less cumbersome by combiningfixation of the trochanter and the osteotomy with a fixed-angle locking plate (Fig. 3). The implant we commonly useallows guide pins to be placed through an aiming device inpreparation for the proximal locking screws of the plate.Initially, a provisional directional guide pin is inserted freehand to direct the version of the eventual screw trajectory.The version is checked by fluoroscopy with the hip in anequivalent to “frog-leg abduction.” The neck-shaft angle ofthis pin is less precise by this technique since the proximal

ined osteoplasty and proximal femoral osteotomy for FAI.f a 12-year-old female 8 months following in situ fixationctivity, obligate external rotationwith hip flexion and painrior and abduction-lateral radiographs of the same patientmoral osteotomy.

M.P. McClincy, P.P. Bosch144

femur will be extended upon fixation. This pin should beplaced fairly posteriorly to allow for “flexed positioning” ofthe aiming device. The aiming device then swings anteriorlyto set the amount of flexion to be accomplished with theosteotomy. This is analogous to what was previously donewith the chisel for a blade plate. The 2 pins to be replaced byscrews are now measured for length and the locking plate(typically a 1101 angle with step off) and appropriate length-locking screws are prepared at the back table. Furthermore,we place a guide pin in the distal femur to judge version.The osteotomy is a single transverse cut made with an

oscillating saw and completed with an osteotome. It should bedone approximately 1-1.5 cm inferior to the pins, roughly atthe inferior level of the trochanter. Owing to the significantrigidity of our locking plate construct, we no longer perform aclosing-wedge osteotomy. This effectively avoids any limbshortening, which had been commonwhen an anterior wedgeof bone was resected to improve bone opposition. The lockingplate is fixed to the proximal femur and trochanter. The2 previously placed guide pins are sequentially replaced bylocking screws. As the provisional guide pin remains in placethroughout, there should always be 2 points of fixation. Afterthe 2 proximal locking screws are placed in the proximalfragment, the trochanter osteotomy is fixed. As the plate wasapplied with an anterior (flexed) trajectory, reducing the plateto the femoral shaft will “extend” the proximal femur and thefemoral head. The plate can be held to the distal femoral shaftwith a Verbrugge or “Turkey-claw” bone clamp (Fig. 4) and isgenerally fixed with standard large fragment (4.5) bicorticalcompression screws. The provisional guide pin and distalfemoral pin help guide rotation. Although internal rotation ofthe distal fragment can “correct” the asymmetric external footprogression angle common in patients with post-SCFE mor-phology, it is our experience that the correction of the head-neck impingement alleviates the obligate external rotation andimproves the foot progression. Thus, we aim to maintain theoriginal femoral version during plate fixation.Upon completion of thefixation,we remove guide pins, and

obtain final digital radiographs. Closure is standard layeredrepair, without a drain. The postoperative course typicallyinvolves a 3-5 days inpatient stay. Postoperative activityrequires 4-6 weeks of touch-down weight bearing, untilhealing of the greater trochanter is evident. Thereafter,weight-bearing and hip abduction exercises are added. After3-4 months, the patient usually regains adequate abductionstrength to increase activity. At this time, their Trendelenburglurch resolves, and marked improvement from preoperativesymptoms becomes apparent (Fig. 5).

DiscussionFemoroacetabular impingement following SCFE has become awell-recognized cause of progressive hip pain and osteo-arthritis after in situ pinning.6,30,31 The proximal femoraldeformity can vary significantly, and multiple interventionsare available for mild to moderate cases including arthro-socopic osteoplasty, surgical dislocation with osteoplasty, or

surgical dislocation with proximal femoral osteotomy. In thecases of severe deformity causing FAI, a combined approachincluding surgical dislocation with both osteoplasty andproximal osteotomy is an effective method of deformitycorrection. While the inclusion of an intertrochanteric osteo-tomy adds a small but real risk of femoral head osteonecrosis, italso provides the benefit of improved deformity correctionwithout excessive resection of the femoral neck deformity.Further studies are required to more specifically evaluate thelong-term effects of this combined procedure on hip function.

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