John C. Clohisy
Perry L. Schoenecker
Over the past decade there has been a renewed focus on joint preservation surgery of the hip. This is owing to an enhanced understanding of the pathogenesis of degenerative hip disease, improved diagnostic imaging modalities, refined patient selection criteria, and more sophisticated surgical techniques. Perhaps most important is an appreciation of the significance of prearthritic and early arthritic hip symptoms that commonly occur before irreversible joint deterioration. These early symptoms provide a window of opportunity for surgical intervention to remedy the underlying hip abnormality and to improve the prognosis of early hip disease. The goals of joint preservation surgery are to alleviate hip symptoms, improve the functional capacity of the hip, and delay or prevent the biologic cascade of degenerative hip disease. Osteotomy surgery about the hip is one of the mainstay joint preservation strategies and will continue to play a major role in the expanding field of hip preservation surgery. Nevertheless, optimal clinical results of osteotomy surgery are realized only through careful patient selection, detailed preoperative planning, accurate surgical procedures, and supervised patient rehabilitation. The goal of this chapter is to summarize the essential concepts of hip osteotomy surgery. The fundamentals of patient evaluation and the basics of osteotomy procedures will be presented for the most common structural disorders of the hip.
Pathogenesis
Advanced hip osteoarthritis is a common condition in the United States as evidenced by the approximately 200,000 total hip arthroplasties performed annually. The cause of hip osteoarthritis is complex and multifactorial and continues to be an area in need of investigation. Patient characteristics including age, gender, genetic makeup, race, occupation, and activity level have all been identified as factors that impact the pathophysiology of this disease. Most relevant to hip joint preservation surgery is the known correlation between structural hip disorders and secondary osteoarthritis. Harris emphasized that over 90% of patients with osteoarthritis had an underlying deformity of the joint that was present at the cessation of growth. This concept underscores the theory that osteoarthritis of the hip is very commonly associated with a pre-existing, mechanical disorder. In the mechanically compromised hip, instability, abnormal joint loading, and/or impingement can produce abnormal shear forces and excessive loads per unit area at the articular surface and induce premature degeneration of the involved articular cartilage. If left untreated, progressive degenerative articular disease ensues and secondary osteoarthritis can develop.
Development dysplasia of the hip (DDH) is the most common structural deformity associated with secondary osteoarthritis and serves as a model of this pathophysiologic cascade. The dysplastic acetabulum is abnormally inclined in the superolateral direction and does not provide adequate anterolateral femoral head coverage. This leads to hip instability and anterolateral acetabular rim overload. As a result of localized overload, labral disease ensues and adjacent articular cartilage deterioration is initiated. Persistent instability and localized joint overload accelerate articular cartilage degeneration and secondary osteoarthritis.
Diagnosis
Patient History and Physical Exam
The patient history is initially focused on determining the cause of the problem and establishing whether the hip joint is the true source of symptoms. Referred pain from other anatomic regions, most commonly the lumbar spine, needs to be excluded. The interview should then elicit any history of childhood or adolescent hip disease, previous hip surgery, hip trauma, risk factors for osteonecrosis, or a history consistent with inflammatory arthritis. If the patient has authentic hip symptoms, the duration, character, and location of pain are determined. The examiner should question about episodes of snapping, popping, or locking that may suggest soft tissue pathology about the hip or a mechanical intra-articular component to the disease. Activities that exacerbate symptoms should be noted. It is important to delineate whether the patient experiences activity-related hip pain consistent with abductor fatigue (lateral hip discomfort or tiring) or instability and associated joint overload
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(anterior or groin discomfort). Alternatively, the symptoms may be more consistent with anterior impingement disease (anterior or groin discomfort) and exacerbation with hip flexion activities and prolonged sitting. The severity of symptoms and functional limitations should also be discussed as patients with early and less advanced symptoms are usually better candidates for osteotomy surgery. The social history should establish the occupation, activity level, and tobacco and alcohol use habits of the patient. The overall medical condition and patient capacity to comply with surgical treatment and rehabilitation are other factors that need to be considered when contemplating osteotomy surgery. The patient should understand the goals of treatment and must be willing to actively participate in a relatively involved postoperative rehabilitation program.
Physical examination findings are of utmost importance in evaluating a patient for hip osteotomy surgery. The general physical status, including body height, weight, and apparent conditioning, is noted. During examination, sitting posture and gait pattern are observed. The hip is inspected with specific attention to the presence and position of surgical scars. The Trendelenburg test and side-lying abduction testing indicate the integrity of hip abductor strength. Abductor weakness is a common finding in patients with early hip disease. Leg-length determination is made with the patient standing, noting the presence or absence of a balanced pelvis. Functional leg-length inequality can be measured by noting the height of a block placed under the short leg necessary to balance the pelvis. Alternatively, measurement of true leg-length inequality can be made with the patient supine, measuring from the anterior superior iliac spine to the medial malleolus and comparing the measurement to the contralateral side. The neurovascular status of the extremity should also be determined, especially in patients with a history of previous hip trauma and/or surgery.
Range of motion of the hip is carefully assessed as is the presence of pain and hip joint irritability during the motion examination. When assessing hip range of motion it is important to steady the pelvis with one hand while the examiner's other hand ranges the ipsilateral hip. This determines motion end points more accurately because the examiner better appreciates forced motion of the pelvis through the hip. With this technique hip flexion, abduction, adduction, and rotation are recorded. Hip internal and external rotation both in extension and flexion are measured. Restricted flexion and internal rotation in flexion should be appreciated as this finding is common in patients with anterior femoroacetabular impingement. Again, careful appreciation of motion end points is important to accurately assess true hip joint motion and to judge the joint suitability for osteotomy surgery. The surgeon must verify that the hip has adequate range of motion to accommodate the proposed reconstruction, because a hip with inadequate motion may respond poorly to an osteotomy procedure. In general, at least 90 degrees of hip flexion should be present. One exception is the patient with a severe slipped capital femoral epiphysis (SCFE) or a posttraumatic deformity in which restricted hip flexion may be secondary to malalignment rather than degenerative changes. In contrast, a patient being evaluated for acetabular reorientation to correct classic acetabular dysplasia must demonstrate adequate hip flexion (≥105 degrees) to tolerate the osteotomy, because improved anterior coverage of the femoral head achieved with the osteotomy will reduce hip flexion motion. Thus, during evaluation the surgeon must determine that a functional motion (at least 90 degrees of flexion) will be maintained postoperatively. Similarly, hip abduction motion will be reduced with a varus-producing proximal femoral osteotomy. Therefore, preoperative hip abduction motion must be adequate (>30 degrees) to accommodate the surgical correction and to maintain adequate clinical abduction postoperatively.
Specific physical exam tests can be helpful in characterizing the underlying hip disease. The impingement test (combined flexion, adduction, and internal rotation) is performed to check for groin discomfort that may indicate labral pathology or the presence of anterior femoroacetabular impingement. This test is also an excellent screening maneuver for any intra-articular disease process and can be extremely helpful in distinguishing an intra-articular from an extra-articular disorder. Additionally, an apprehension test (extension, adduction, and external rotation) evaluates anterior stability of the hip. This maneuver elicits hip (groin) pain in the setting of an unstable dysplastic hip with insufficient anterior coverage and associated anterior instability. A positive test is common with moderate to severe acetabular dysplasia, yet hips with mild acetabular dysplasia may not be sensitive to anterior stability testing.
Radiographic Evaluation
The radiographic evaluation defines the structural anatomy of the hip in a comprehensive fashion, determines the severity of secondary osteoarthritis, and provides information regarding the effect of osteotomy correction (congruency and joint space alteration). A thorough radiographic examination of the hip is extremely important in optimizing patient selection for surgery, preoperative planning, and accurate surgical technique. To accomplish this, we obtain a full hip series including a standing anteroposterior pelvis and false profile. Frog and cross-table laterals of the hip are taken supine. When considering an osteotomy, functional radiographs are obtained to check congruency in a position mimicking the osteotomy. These radiographs are performed with the surgeon or assistant holding the extremity and are used to confirm clinical comfort in a position of radiographic congruency. For example, a flexion-abduction view is obtained to assess the hip articulation in anticipation of acetabular reorientation for treatment of classic acetabular dysplasia. This radiograph mimics the joint congruency and improved anterolateral femoral head coverage to be achieved by the osteotomy. Similarly, an abduction functional view is performed to assess the hip for a varus-producing proximal femoral osteotomy. These functional radiographs should demonstrate joint congruency without hinging and ideally show an improvement or at least maintenance of the joint space. If congruency or the optimal joint reorientation position is questionable with functional radiographs, a hip exam with fluoroscopy can provide additional information regarding the joint suitability for osteotomy surgery. With more complicated deformities, fluoroscopic examination can be
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extremely informative regarding congruency of the articulation and for planning an optimal osteotomy correction.
Adjunctive imaging tests are frequently obtained to thoroughly evaluate and define the disease pattern of the hip being considered for surgery. Magnetic resonance arthrogram may be indicated to assess acetabular labral disease, articular cartilage integrity, acetabular rim pathology, and femoral head and femoral neck anatomy. Alternatively, a CAT scan of the hip can be useful for more detailed characterization of osseous abnormalities and can facilitate preoperative planning. Sources of bony impingement, femoral head/neck junction anatomy, version of the acetabulum, and osteonecrotic lesion size and location are also better defined with CAT scan images. Clearly, preoperative assessment of all disease components (both acetabular and femoral) enables the surgeon to develop a comprehensive treatment plan and optimize the results of the procedure.
Treatment
Indications and Contraindications
The general indications and contraindications for hip osteotomy surgery are summarized in Table 10-1. It is extremely important to emphasize that several patient-related variables are considered when selecting patients for surgery and when devising a specific treatment plan. Osteotomy surgery has distinct indications, contraindications, and goals when compared with total joint replacement surgery.
Young and middle-aged patients who present with authentic hip symptoms and have an associated structural abnormality should be considered for osteotomy surgery. Typically, an optimal surgical candidate is relatively young (physiologically less than 50 years old), well-conditioned, and active. The hip has a correctable deformity, sufficient range of motion, adequate congruency, and has not progressed to advanced secondary osteoarthritis. The patient should have an understanding of the hip problem and the proposed surgical procedure and should be willing to comply with the postoperative rehabilitation protocol. Nonoperative measures, including physical therapy, activity restriction, and nonsteroidal anti-inflammatory medicines, can be used to minimize symptoms, although a long-term benefit from these modalities is unlikely. Nonsurgical measures as a primary treatment are reserved for patients who are marginal or poor candidates for an osteotomy and for patients not interested in a major hip surgery.
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TABLE 10-1 General Indications and Contraindications for HIP Osteotomy Surgery |
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Various structural hip disorders can present with prearthritic or early arthritic hip symptoms prior to the development of advanced joint deterioration. In general, prearthritic conditions predispose the hip to dynamic instability, localized joint overload, impingement, or a combination of these factors. If these disorders are diagnosed early, the effects of corrective osteotomy surgery can be extremely beneficial (Tables 10-2 and 10-3). The goals of this type of surgery are to correct the underlying structural abnormality of the hip, relieve the patient's discomfort, enhance hip function and activity, and delay or prevent the progression of hip joint deterioration. Osteotomy correction can improve the structure and biology of the joint in various ways. Surgical correction can normalize the structural anatomy of the hip, enhance stability, relieve or prevent
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impingement, optimize congruency, decrease localized articular surface overload, and improve the biomechanics of the joint. It is important to emphasize that joint instability and impingement can be simultaneous problems. Reconstructive techniques must aim to improve joint function by optimizing the dynamic balance between joint stability and impingement.
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TABLE 10-2 Osteotomy Procedures for Specific HIP Disorders |
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TABLE 10-3 Clinical Results of HIP Osteotomy Surgery (Selected Studies) |
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Distinct types of hip disease have unique pathophysiologic mechanisms of joint deterioration. Thus, the techniques of osteotomy reconstruction must be individualized to the underlying structural abnormality of the hip and to the specific disease characteristics of each case. The most common conditions amenable to joint preservation surgery include classic developmental dysplasia (DDH), Perthes-like deformities, SCFE, osteonecrosis, and posttraumatic deformities.
Developmental Dysplasia of the Hip and Techniques of Hip Osteotomy
Classic DDH is the most common indication for joint preservation osteotomy surgery of the hip. This disease is characterized by deficient anterolateral femoral head coverage, superolateral inclination of the acetabular articular surface, a lateral position of the hip center, and variable version abnormalities of the acetabulum. On the femoral side, coxa valga, excessive anteversion, and a nonspherical femoral head are common. This combination of abnormalities can result in joint instability, localized anterolateral joint overload, acetabular labral disease, and eventual secondary arthrosis. In the presence of a congruent joint and in the absence of advanced secondary osteoarthritis, symptomatic DDH is an excellent indication for a reconstructive acetabular osteotomy.
Although various acetabular osteotomy techniques have been described, the Bernese periacetabular osteotomy (PAO) has gained worldwide popularity over the past decade. This is our preferred technique because the osteotomy is performed with an abductor-sparing approach, uses orthogonal osteotomy cuts, and preserves the posterior column. It enables major multiplanar corrections, preserves acetabular fragment blood supply, provides reliable healing, and enables accelerated rehabilitation. The procedure is most commonly performed through a modified Smith-Peterson approach, and four periacetabular cuts are made to enable acetabular mobilization. The first cut is an infra-acetabular osteotomy that starts just below the inferior lip of the acetabulum, aims toward the middle of the ischial spine, and extends to the level of a trajectory bisecting the posterior column (approximately 1 cm anterior to the posterior cortex of the posterior column). The inferior osteotomy is followed by the superior pubic ramus cut, which is made just medial to the iliopectineal eminence and angled away from the joint. The third cut is made at the anterior superior iliac spine directly towards the sciatic notch. The fourth and final osteotomy cut is made with a goal of bisecting the posterior column between the articular surface anteriorly and the posterior cortex. This osteotomy meets the first infra-acetabular cut posteroinferior to the acetabulum. The acetabular fragment is then mobilized and repositioned with internal rotation, forward tilt, and medial translation. The internal rotation component of the reduction provides lateral coverage and maintains anteversion of the acetabulum. The acetabulum is fixed provisionally with k-wires, the reduction is assessed with intraoperative radiographs, and definitive fixation is then performed. Final radiographs are obtained to confirm an osteotomy correction that improves anterolateral femoral head coverage (lateral center-edge angle 20 to 30 degrees, anterior center-edge angle 15 to 25 degrees), reduces the superolateral inclination of the acetabular articular surface (0 to 15 degrees), restores a more medial position of the hip joint center (medial aspect of the femoral head 5 to 10 mm lateral to ilioischial line), and maintains anteversion of the acetabulum (Fig. 10-1A, B).
Version is assessed by the relative positions of the anterior and posterior lips, and it is important that the acetabulum not be overreduced or retroverted, as this can result in secondary anterior femoroacetabular impingement. Slight undercorrection is preferred over excessive
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correction to avoid creating an femoroacetabular impingement. Additionally, hip flexion and abduction motion is checked clinically, and it is imperative that at least 90 degrees of passive hip flexion and 30 degrees of abduction are achieved on the operating room table. After range of motion evaluation, we perform an arthrotomy to inspect the integrity of the acetabular labrum and to assess for anterior femoroacetabular impingement. Large, unstable labral tears are repaired with suture anchors, whereas stable tears are left untreated. Lack of femoral head/neck offset can result in anterior femoroacetabular impingement postoperatively and can be treated with osteoplasty if found to be a source of impingement. In cases with an associated major femoral deformity, a proximal femoral osteotomy may be necessary. In severely dysplastic hips, a valgus proximal femoral deformity may have to be treated with a varus-producing intertrochanteric osteotomy to optimize the reconstruction. Long-term clinical results of the Bernese periacetabular osteotomy, as reported by Siebenrock et al., have demonstrated good to excellent results in 73% of patients followed for an average of 11.3 years. These data are derived from the learning curve experience with this osteotomy. It is likely that with contemporary patient selection criteria and refined surgical techniques, the good clinical results of this procedure will be longer lasting and more predictable.
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Figure 10-1 Standard periacetabular osteotomy (PAO) for developmental dysplasia of the hip (DDH). Preoperative (A) and postoperative (B) anteroposterior pelvic radiographs in a 19-year-old male collegiate athlete with hip pain and instability symptoms. He was treated with staged bilateral periacetabular osteotomies. Note the enhanced lateral coverage, decreased superolateral inclination of the acetabular articular surface, maintained anteversion, and medial translation of the hip center achieved with the osteotomy. The patient returned to full sport activities without restrictions and an excellent clinical outcome. |
As noted previously, the major deformity in classic DDH is usually on the acetabular side of the joint, and currently, most surgeons prefer to address the disease with acetabular reorientation. Uncommonly, the acetabular deformity is very mild and the most profound deformity is femoral-based. It consists of coxa valga with lateral joint overload. In these occasional cases a varus-producing proximal femoral osteotomy can be considered. Perhaps more commonly, a varus-producing proximal femoral osteotomy is indicated to augment the acetabular procedure in severe cases. The varus correction can be combined with extension (apex anterior correction) to enhance hip stability by containing the femoral head anterolaterally and can decrease the load per unit surface area along the anterolateral acetabularrim.
For proximal femoral osteotomies, we prefer a no-wedge technique to obtain correction and minimize the distortion of the proximal femur (Figs. 10-2, 10-3). A varus-producing realignment is performed with a transverse osteotomy at the superior aspect of the lesser trochanter and a 90-degree blade plate for reduction and fixation of the osteotomy fragments. The angle of the chisel and blade insertion dictates the amount of varus correction obtained. For example, if the blade is inserted at a 110-degree angle to the femoral shaft in the frontal plane, a 20-degree correction will be obtained when the 90-degree blade plate is inserted and the osteotomy is reduced. The blade length is estimated with templates and the blade plate offset (10, 15, or 20 mm) is determined to maintain the horizontal offset between the center of the femoral head and the longitudinal axis of the femoral shaft. Specifically, offset is maintained by medial displacement of the femoral shaft for varus osteotomies and lateral displacement for valgus osteotomies. A varus osteotomy shortens the extremity, and the preoperative plan determines the amount of shortening to be produced. For valgus-producing osteotomies, an angled blade plate (110, 120, or 130 degrees) is used. The amount of valgus correction is determined by the angle of insertion and the blade plate angle. For example, a 20-degree correction is obtained by inserting a 110-degree blade plate at a 90-degree angle to the femoral shaft in the frontal plane. With reduction of the osteotomy and fixation of the plate, a 20-degree correction is obtained. Valgus osteotomies lengthen the extremity, and resection of bone may be required to maintain equal leg lengths.
The patient is positioned supine, and a standard lateral approach to the proximal femur is performed. The Watson-Jones interval can be used for access to the anterior hip joint, acetabular labrum, femoral head, and femoral neck if
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necessary. K-wires are placed to guide the osteotomy cut and the blade insertion. To place the blade centrally in the femoral neck, it must be inserted in the anterior half of the lateral greater trochanter owing to the posterior overhang. The insertion site should provide a 1.5- to 2.0-cm bony bridge of lateral femur cortex between the blade entry point and the osteotomy site. This minimizes the risk of fracture in this location. In general, varus and flexion/extension osteotomies are performed with a 90-degree blade plate whereas valgus corrections are obtained with blade plates ranging from 110 to 130 degrees, depending on the magnitude of correction. The chisel is advanced with a K-wire guiding the direction of insertion in the frontal plane and centrally in the femoral neck. If flexion (apex posterior) or extension (apex anterior) of the osteotomy is desired, this is incorporated by adjusting the anterior/posterior angulation of the chisel with respect to the femoral shaft. Rotation of the femur is then marked and the transverse osteotomy is made with an oscillating saw at the upper level of the lesser trochanter. The blade chisel is removed from the proximal fragment and the blade plate inserted along the prepared track. The blade plate is further secured to the proximal fragment with a 4.5-mm cortical screw. The proximal and distal osteotomy fragments are then mobilized, and the osteotomy is reduced by approximation of the lateral femur to the plate. The rotation line is used to facilitate the reduction, and care should be taken to align the two fragments without a major step-off in the anteroposterior plane. Final reduction and fixation of the osteotomy is assessed with radiographs or fluoroscopy in the anteroposterior and lateral planes, and hip range of motion (flexion and rotation) is checked by clinical examination.
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Figure 10-2 Periacetabular osteotomy/proximal femoral osteotomy (PAO/PFO) for Perthes/no wedge technique. Preoperative anteroposterior pelvic radiograph (A) of a 21-year-old male with a history of Perthe disease in childhood, leg-length discrepancy and a 2-year history of progressive lateral hip pain. A Perthe deformity of the proximal femur is noted, and secondary acetabular dysplasia is present. This patient was treated with a combined periacetabular osteotomy and a valgus proximal femoral osteotomy (B). The femoral osteotomy lengthened the extremity, enhanced the congruency of the joint, improved clinical abduction, and improved abductor function. This patient had an excellent clinical result 4 years later (C). |
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Figure 10-3 Proximal femoral osteotomy (PFO) for posttraumatic malunion. Standing anteroposterior pelvis (A) of the left hip in a 39-year-old female referred for evaluation of persistent hip pain after treatment of an intertrochanteric femoral fracture. Prior to fracture, the patient was an active recreational runner. She presented complaining of lateral hip pain, leg-length discrepancy, and lack of internal rotation of the left hip. On examination she had a severe limp, profound abductor weakness, a 2-cm leg-length discrepancy, and malrotation with <10 degrees of internal rotation. This proximal femoral malunion was treated with a valgus-derotation femoral osteotomy (B). She had an excellent clinical result and was asymptomatic at 5-year follow-up (C). |
Perthes Deformities
Legg-Calve-Perthes disease of childhood commonly alters the development of the femoral head and acetabulum, resulting in residual deformities that can be associated with hip symptoms in adulthood and can lead to secondary osteoarthritis. Perthes abnormalities are most remarkable on the femoral side (coxa magna, coxa plana, coxa breva, and relative trochanteric overgrowth), but can also encompass a secondary acetabular dysplasia. Generally, these abnormalities are very complex and must be evaluated carefully to optimize the surgical treatment plan. Labral disease, instability and joint overload, joint incongruence, abductor fatigue, and femoroacetabular impingement can all contribute variably to patient symptoms and should be considered.
The primary goals of treating Perthes deformities are to enhance joint stability, decrease localized joint surface overload, and relieve intra-articular impingement. Additional treatment goals may include equalization of leg lengths and repositioning of the greater trochanter. The specific characteristics of the deformity dictate the type of osteotomy correction. Hips with a femoral deformity and an associated secondary acetabular dysplasia (the most common scenario for patients who present with a prearthritic or early arthritic Perthes-like deformity) are most reliably treated with a combined acetabular reorientation and proximal femoral valgus osteotomy (Fig. 10-2A–C). With this comprehensive approach, the acetabular and femoral deformities can be addressed to optimize the hip reconstruction. This treatment strategy has been reported by Beck and Mast with good to excellent clinical results in 85% of cases at an average 3.4-year follow-up. At surgery, we now perform an arthrotomy to inspect the integrity of the acetabular labrum and to assess anterior femoroacetabular impingement from the large, nonspherical femoral head. Osteoplasty of the prominent anterior femoral head in the setting of coxa magna can minimize femoroacetabular impingement after acetabular reorientation.
For patients with a major, primary femoral deformity, a valgus osteotomy can be effective in improving congruency, relieving intra-articular impingement, lengthening the extremity, improving abductor function, and enhancing clinical hip abduction. Osteoplasty of the femoral head/neck junction may also be indicated in conjunction with the femoral osteotomy to completely address impingement disease. For Perthes hips with a less severe femoral deformity and a primary impingement problem, a femoral head/neck junction osteoplasty alone may be considered.
Slipped Capital Femoral Epiphysis
Another cause of hip dysfunction in the young patient, and premature osteoarthritis in adulthood, is a residual deformity from a SCFE. The SCFE deformity most commonly involves posteromedial displacement of the epiphysis, resulting in an extension and retroversion deformity of the proximal femur. An apparent varus deformity is also present. These patients most commonly complain of restricted hip flexion and symptoms from anterior femoroacetabular impingement combined with an external rotation deformity of the involved lower extremity. Direct correction of this deformity can be performed at the level of the femoral neck, although the risk of osteonecrosis makes this technique less attractive. Alternatively, a transverse intertrochanteric osteotomy can adequately address the deformity with less risk of osteonecrosis. A flexion and derotation osteotomy can correct the deformity and markedly improve clinical symptoms. The flexion correction should aim to place the femoral shaft perpendicular to the epiphysis in the sagittal plane. Slight valgus can be incorporated into the osteotomy but is frequently obtained with the flexion correction alone. An anterior capsulotomy should also be performed to ensure unrestricted postoperative hip extension and to inspect for residual femoroacetabular impingement. If present, the prominent anterolateral femoral head/neck junction should be resected. Severe SCFE deformities can require major deformity corrections (>50 degrees). In these cases it is particularly important to align the proximal and distal fragments by combining anterior translation and flexion of the distal fragment. This preserved alignment facilitates future total hip arthroplasty surgery.
Long-term results of intertrochanteric osteotomy for the treatment of SCFE deformities support continued use of these procedures. One recent follow-up study of the Imhauser osteotomy demonstrated good to excellent results in 77% of patients followed for an average of 23.4 years. This osteotomy provides a multiplanar correction
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consisting of flexion, internal rotation, and valgus that is dictated by resection of a three-dimensional intertrochanteric bone wedge. A similar multiplanar realignment can also be achieved with the no-wedge osteotomy technique discussed previously.
Osteonecrosis of the Femoral Head
The surgical management of osteonecrosis of the femoral head is a controversial topic, and there are many acceptable treatment options depending on patient characteristics, stage, size, and location of the lesion. The literature does support the intertrochanteric osteotomy as an effective strategy for the treatment of very specific disease patterns. It is imperative that these patients are carefully selected, and various factors must be considered when contemplating an intertrochanteric osteotomy for the diagnosis of osteonecrosis. Patients with a subchondral fracture and/or femoral head collapse without significant joint space narrowing can be evaluated as potential candidates for osteotomy surgery. The ideal candidate is a compliant, healthy patient not on corticosteroids who has a lesion with a combined osteonecrotic angle on the anteroposterior and lateral radiographs of <200 degrees. Such patients represent a relatively small subgroup of the patient population with osteonecrosis. In general, anterolateral lesions that can be delivered away from the weight-bearing surface of the femoral head are treated with a flexion-valgus osteotomy. This repositions the healthier posteromedial femoral head articular cartilage and subchondral bone into the weight-bearing zone. Anteromedial lesions that cannot be delivered away from the weight-bearing zone with a valgus osteotomy are managed with a varus flexion osteotomy to use the healthy posterolateral femoral head as the primary weight-bearing surface. In well-selected candidates treated with sound surgical technique, proximal femoral osteotomy can be very effective. Mont et al. reviewed 37 varus osteotomies (26 with a combined flexion or extension component) in the treatment of Ficat stage II and III disease. At 11.5 year follow-up, they noted 76% good or excellent clinical results.
Posttraumatic Hip Disorders
Selected posttraumatic disorders of the proximal femur can be excellent indications for osteotomy surgery. For example, nonunions of the femoral neck are associated with profound clinical symptoms and can be effectively managed with a valgus-producing proximal femoral osteotomy in appropriate patients. With the Pawuel technique, a laterally based closing wedge osteotomy at the intertrochanteric level achieves valgus correction. This converts the tension and shear forces across the nonunion (secondary to varus displacement) to a compressive force that facilitates healing. Marti et al. reviewed 50 cases of femoral neck nonunion treated with the Pawuel valgus-producing osteotomy at an average 7.1-year follow-up. They observed 86% of the nonunions to be healed, whereas 14% had been converted to total hip replacements.
Proximal femoral malunions may also present as a source of hip dysfunction, especially in active young patients. Such deformities must be carefully characterized, and the corrective osteotomy is planned to address the specific malunion pattern of each case. In the intertrochanteric region, a transverse osteotomy at the superior aspect of the lesser trochanter and the no-wedge technique can be used to correct multiplanar deformities and obtain predictable healing (Fig. 10-3).
Postoperative Management
Patients treated with a periacetabular osteotomy or proximal femoral osteotomy are mobilized on the first or second postoperative day. For the first 6 weeks, patients bear 30 pounds partial weight and perform isometric exercises only. At 6 weeks, active strengthening exercises are initiated with an emphasis on abductor strengthening, and weight-bearing status is advanced to 5% for an additional 4 weeks. Ten to 12 weeks postoperatively patients advance to full weight bearing depending on the details of the case and radiographic signs of healing. Aggressive hip strengthening is then permitted at this phase of rehabilitation. Unrestricted activity is allowed when radiographic healing of the osteotomy is evident. In general, we recommend hardware removal 1 to 2 years after the osteotomy to facilitate future conversion to total hip arthroplasty if required. Removal of proximal femoral blade plates also reduces the risk of trochanteric bursitis symptoms associated with the retained hardware.
Complications
Potential complications of osteotomy hip surgery include infection, nonunion, fixation failure, neurovascular injury, thromboembolic disease, and perioperative medical problems. A learning curve is known to contribute to the incidence of complications for most surgeons. Unique to acetabular osteotomy surgery are the potential complications of intra-articular fracture and overcorrection. Intra-articular fracture has a poor prognosis and usually leads to rapid joint deterioration. Overcorrection can cause secondary impingement disease and must be kept in mind when planning and performing acetabular reorientation. Persistent hip symptoms and progression of secondary osteoarthritis are additional problems that can occur; they underscore the limitations of joint preservation surgery in the setting of major degenerative changes and emphasize the importance of careful patient selection.
Suggested Readings
Beck M, Mast JW. The periacetabular osteotomy in Legg-Perthes–like deformities. Semin Arthroplasty. 1997; 8(1):102–107.
Clohisy JC, Barrett SE, Gordon JE, et al. Periacetabular osteotomy for the treatment of severe acetabular dysplasia. J Bone Joint Surg Am. 2005;87(2):254–259.
Diab M, Hresko MT, Millis MB. Intertrochanteric versus subcapital osteotomy in slipped capital femoral epiphysis. Clin Orthop Relat Res.2004;427:204–212.
Ganz R, Klaue K, Vinh TS, et al. A new periacetabular osteotomy for the treatment of hip dysplasias. Technique and preliminary results.Clin Orthop. 1988;232:26–36.
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Harris WH. Etiology of osteoarthritis of the hip. Clin Orthop. 1986;213:20–33.
Kartenbender K, Cordier W, Katthagen BD. Long-term follow-up study after corrective Imhauser osteotomy for severe slipped capital femoral epiphysis. J Pediatr Orthop. 2000;20:749–756.
Leunig M, Siebenrock KA, Ganz R. Rationale of periacetabular osteotomy and background work. J Bone Joint Surg Am. 2001;83:438–448.
Marti RK, Schuller HM, Raaymakers EL. Intertrochanteric osteotomy for non-union of the femoral neck. J Bone Joint Surg Br. 1989;71:782–787.
Millis MB, Kim YJ. Rationale of osteotomy and related procedures for hip preservation: a review. Clin Orthop Relat Res. 2002;405:108–121.
Mont MA, Fairbank AC, Krackow KA, et al. Corrective osteotomy for osteonecrosis of the femoral head. J Bone Joint Surg Am. 1996;78:1032–1038.
Myers SR, Eijer H, Ganz R. Anterior femoroacetabular impingement after periacetabular osteotomy. Clin Orthop Relat Res. 1999;363:93–99.
Siebenrock KA. Scholl E, Lottenbach M, et al. Bernese periacetabular osteotomy. Clin Orthop. 1999;363:9–20.
Trousdale RT, Ekkernkamp A, Ganz R, et al. Periacetabular and intertrochanteric osteotomy for the treatment of osteoarthrosis in dysplastic hips. J Bone Joint Surg Am. 1995;77(1):73–85.