Vol 7, No 5, September/October 1999 325 Although the true incidence of per- sistent acetabular dysplasia in adults is unknown, its role as a sig- nificant cause of premature hip osteoarthritis is well established. 1-4 It is estimated that between 20% and 50% of cases of degenerative disease of the hip are secondary to subluxation or acetabular dyspla- sia. 3 In a classic study of 130 pa- tients with degenerative arthritis of the hip, Stulberg and Harris 2 found that 63 patients (48%) had underly- ing acetabular dysplasia. Ideally, patients with acetabular dysplasia and subluxation are identified and treated in infancy. Failing this, treatment instituted as early as possible in childhood, preferably before age 4, will take maximum advantage of the inher- ent remodeling capabilities of the hip joint. 5 In the older child or young adult, recognition of persis- tent acetabular dysplasia may at least allow treatment before the onset of irreversible cartilage in- jury and thereby favorably influ- ence an otherwise worrisome nat- ural history. The goal of treatment of patients with persistent acetabular dysplasia is to forestall or prevent the devel- opment of osteoarthritis and to obviate the need for arthroplasty at a relatively young age. Pelvic oste- otomies can play a central role in this strategy by reorienting the architecture of the pelvis so as to normalize the forces of weight bear- ing. To enhance understanding of this important tool in the preven- tion of hip osteoarthritis, we will outline the general categories of pelvic osteotomies, discuss the indi- cations for their use, and provide a brief technical description of those that are most commonly utilized in current practice. Etiology and Biomechanics of Acetabular Dysplasia The abnormally steep acetabular roof and the shallow joint surface Dr. Gillingham is Director, Division of Pediatric Orthopedics, Departments of Ortho- pedics and Clinical Investigation, Naval Medical Center, San Diego, Calif; and Assistant Professor of Surgery, Uniformed Services University, Bethesda, Md. Dr. Sanchez is Head, Department of Orthopedics, Naval Hospital, Twenty-nine Palms, Calif. Dr. Wenger is Director of Pediatric Orthopedics, Children’s Hospital, San Diego; and Clinical Professor of Orthopedic Surgery, University of California, San Diego. Reprint requests: Dr. Gillingham, Department of Clinical Investigation, Naval Medical Center San Diego, Suite 5, 34800 Bob Wilson Drive, San Diego, CA 92134-1005. The Chief, Bureau of Medicine and Surgery, Navy Department, Washington, DC, Clinical Investigation Program, sponsored this report S93-094 as required by NSHSBETHINST 6000.41A. The views expressed in this article are those of the authors and do not reflect the official policy or position of the Department of the Navy, the Department of Defense, or the United States Government. Abstract Persistent acetabular dysplasia is a well-known cause of premature hip osteoarthritis. In the dysplastic hip, point loading occurs at the edge of the steep, shallow acetabulum. Pelvic osteotomies reduce this load by increasing the contact area, relaxing the capsule and muscles about the hip, improving the moment arm of the hip, and normalizing the forces of weight bearing. The orthopaedic surgeon can choose from among a variety of pelvic osteotomies (e.g., redirectional, reshaping, and salvage) for the purpose of restoring normal anato- my and biomechanical forces across the hip joint. Treatment of residual dyspla- sia is based on the patient's age and the presence or absence of congruent hip reduction. A Salter or Pemberton procedure is generally appropriate for a child between the ages of 2 and 10. A triple innominate osteotomy can be considered for the older child or adolescent in whom the triradiate cartilage remains open. After triradiate closure, the Ganz periacetabular osteotomy can be considered in addition to the triple innominate osteotomy. J Am Acad Orthop Surg 1999;7:325-337 Pelvic Osteotomies for the Treatment of Hip Dysplasia in Children and Young Adults CDR Bruce L. Gillingham, MC, USN; LCDR Anthony A. Sanchez, MC, USNR; and Dennis R. Wenger, MD that characterize acetabular dyspla- sia can be due to several causes. Although acetabular dysplasia is most commonly seen as a compo- nent of developmental dysplasia of the hip (DDH), it can also be a residual of Legg-Perthes disease and is frequently seen in patients with neuromuscular diseases, such as cerebral palsy and myelomenin- gocele. The importance of a concentric hip reduction during development of both components of the hip joint is well known. 5,6 The development of appropriate acetabular depth depends in large part on the stimu- lus of the femoral head pushing into the triradiate cartilage. Conversely, if the femoral head is to achieve its normal spherical shape in adult- hood, it must be well seated within the acetabulum during infancy and early childhood. Any condition that interferes with this interdependent relationship can lead to acetabular dysplasia. Left untreated, a mean- ingful reduction in the longevity of the hip joint can result. 2 When evaluating an infant or child with acetabular dysplasia, it is important to ascertain whether there is associated hip subluxation. Disruption of ShentonÕs line on a standing anteroposterior (AP) radio- graph of the pelvis indicates that the femoral head is proximally and laterally subluxated. (ShentonÕs line is created by drawing a line along the proximal medial femoral metaphysis and extending onto the superior border of the obturator foramen. In a normal hip, the line is an arc of continuous contour.) If the condition is not treated, prema- ture joint degeneration and clinical disability predictably follow. The age at onset of symptoms correlates well with the severity of the sublux- ation. 2,4,7 The patients with the most serious disease begin to expe- rience pain in the second decade; those with the least serious disease may reach the fifth decade before noting symptoms. 7 However, even in moderate cases, functionally dis- abling symptoms can occur during the most vigorous and productive years of life. Less predictable is the effect of acetabular dysplasia without sub- luxation. Patients without subluxa- tion are frequently asymptomatic, and osteoarthritis tends to develop much later and less commonly than in patients with subluxation. 1 Cooper- man et al 1 concluded that the usual radiographic indices by which acetabular morphology is character- ized are not predictive of the rate at which osteoarthritis develops in patients with acetabular dysplasia alone. In a more recent study of the contralateral hip in patients who had undergone a total hip replace- ment for osteoarthritis secondary to dysplasia, Murphy et al 8 noted a significant (P<0.0001) difference in standard radiographic indices be- tween patients in whom osteoarthri- tis developed in the opposite hip before age 65 and those in whom it did not. Adolescent patients with acetabular dysplasia without associ- ated subluxation should be carefully evaluated for clinical findings, as they (particularly females) are at greater risk than the general popu- lation for the development of clini- cal signs and symptoms of degener- ative hip disease. 2 Acetabular dysplasia eventually results in degenerative joint disease due to alterations in load. In a study of patients followed up for an average of 29 years after reduction of a congenitally dislocated hip, Hadley et al 9 concluded that over the long term, articular cartilage can tolerate mean contact pressures of 2 MPa, with an inverse relation- ship between higher pressures and the time needed to develop degen- erative changes. In a normal hip, peak acetabular contact pressures may be as high as 10 MPa, depend- ing on activity, but are distributed throughout the entire acetabulum, with the dome being subjected to the highest pressure and the rim to essentially none. 10 In the dysplastic hip, point load- ing occurs at the edge of the steep, shallow acetabulum. Pelvic oste- otomies reduce this load by in- creasing contact area, relaxing the capsule and muscles about the hip, and improving the moment arm of the hip. 10 Clinical Evaluation History and Physical Examination The initial evaluation focuses on a characterization of the patientÕs symptoms, activity level, functional limitations, and expectations. The patient with residual dysplasia may be asymptomatic or may experience only vague discomfort with strenu- ous weight-bearing activities. The presence of more extensive com- plaints may suggest that degenera- tive arthritis is already established. Most children and teenagers with radiographic evidence of severe subluxation that requires treatment will have no symptoms. Physical examination includes inspection of the extremity for muscle wasting of the quadriceps and gluteus, longitudinal malalign- ment of the limb, and limb-length discrepancy. Analysis of the pa- tientÕs gait may reveal a limp or an abductor lurch. Palpation of the posterior iliac crest is performed with the patient standing, in order to detect pelvic obliquity. The Trendelenburg test, performed both immediately and after a 20- second delay, allows assessment of the competence and resistance to fatigue of the hip abductors. The range of hip motion is carefully documented, with particular atten- tion paid to hip rotation and the presence of contractures. Pain with active or passive motion sug- gests synovitis or impingement. Pelvic Osteotomies for Hip Dysplasia Journal of the American Academy of Orthopaedic Surgeons 326 Pain elicited by internal rotation of the flexed and adducted hip may signify the presence of a de- tached limbus. Termed Òacetabu- lar rim syndromeÓ by Klaue et al, 11 this condition is considered to be a precursor of osteoarthritis of the hip in patients with acetabular dysplasia. Most children and ado- lescents, even those with severe dysplasia, have few, if any, physi- cal findings. Radiologic Evaluation A comprehensive radiographic evaluation is essential to clarify the degree of deformity before per- forming a hip osteotomy. The ini- tial plain films should include weight-bearing (standing) AP, frog- leg lateral, and abductionÐinternal rotation views of the pelvis and hips, as well as a faux profil (French for Òfalse profileÓ) view of the affected hip. Analysis of the AP view should include a qualitative assessment of ShentonÕs line and the acetabular sourcil (a term derived from the French word for ÒeyebrowÓ). As mentioned previously, a break in the normal smooth arc of ShentonÕs line is suggestive of hip subluxation. The appearance of the acetabular sourcil is a sensitive radiographic indicator of asymmetric loading of the hip joint. 12 Ordinarily, this dense subchondral bone appears as a smooth curve of uniform thick- ness. In the dysplastic hip, lateral sourcil thickening occurs, which represents increased focal loading due to underlying malalignment (Fig. 1). Careful analysis of the sourcil, especially if there is side-to- side asymmetry, is an important tool for the hip surgeon. Measurements of the center- edge angle of Wiberg, 4 the adult acetabular angle of Sharp, 13 and the acetabular depth are useful means of quantitating the severity of the dysplasia. Prior to ossification of the femoral head, the acetabular index is generally used to assess acetabular configuration, with nor- mal mean values decreasing to less than 20 degrees by age 24 months (Table 1). 14 The abductionÐinternal rotation view neutralizes femoral antever- sion and allows accurate assess- ment of the true femoral neck-shaft angle. In addition, this view simu- lates the coverage possible with a proximal femoral varus osteotomy. A single innominate osteotomy can be simulated by taking a radio- CDR Bruce L. Gillingham, MC, USN, et al Vol 7, No 5, September/October 1999 327 Fig. 1 Anteroposterior radiograph of the pelvis of an 18-year-old girl with left hip dyspla- sia. The right acetabular sourcil appears as a smooth curve of uniform thickness. In con- trast, the left sourcil is wider laterally, indicating focal loading. Table 1 Radiographic Assessment of the Hip * Measurement Normal Dysplastic Children Acetabular index at 3 months, degrees Boys 22 ± 4 ³27 Girls 25 ± 3.5 ³29 Acetabular index at 24 months, degrees Boys 19 ± 3.6 ³24 Girls 18 ± 3.5 ³23 Adults Acetabular angle, degrees 25-41 ³43 Acetabular depth, mm 15-27 <15 mm in men, <14 mm in women Acetabular roof, degrees >0 ²0 Center-edge angle, degrees 24-46 ²20 * Based on data reported by Stulberg and Harris, 2 Wiberg, 4 and Scoles et al. 14 Normal values represent mean ± 2 SD. graph with the hip held in 25 de- grees of flexion, 10 degrees of ab- duction, and neutral rotation, with the x-ray beam directed posteriorly and caudally 25 degrees. 15 The faux profil view, first de- scribed by Lequesne and de S•ze 16 in 1961, is a true lateral view of the acetabulum made with the patient standing with the pelvis rotated 25 degrees toward the x- ray beam. The result is a center- edge angle-type assessment of an- terior coverage. Fluoroscopic examination of the hip in various positions can be a useful means of gauging the effect of a proposed osteotomy. Arthrog- raphy is of particular value when assessing the incompletely ossified femoral head of a child. The recent advances in three- dimensional reconstruction of computed tomographic (CT) stud- ies have greatly expanded our understanding of the underlying pathoanatomy in patients with residual acetabular dysplasia. This modality is emerging as a valuable preoperative tool for sur- gical decision making and plan- ning. 17,18 The three-dimensional display provides superior infor- mation about the fit of the femoral head in the acetabulum, as well as the size, shape, and orientation of the acetabulum. This increased detail has clearly demonstrated that acetabular dysplasia is more complex than previously thought. More than just malrotation or maldirection, acetabular dysplasia is a combination of acetabular maldirection, margin erosion, tor- sion, hypoplasia (localized or global), abnormal shape, and decreased acetabular surface area. 19 With this greater under- standing has come an improved ability to match the osteotomy to the type of acetabular deficiency. In addition, comparison of the ini- tial study with one performed postoperatively is a valuable tool in assessing the success of the osteotomy in reproducing normal hip architecture and will further refine the surgeonÕs ability to choose the appropriate osteotomy. Treatment Overview The goal of treatment of the patient with acetabular dysplasia is to establish normal biomechanical forces about the hip joint. The means by which this can be accom- plished vary greatly depending on the patientÕs age, the severity of dysplasia, and the morphology of the hip joint (Fig. 2). In the infant and young child, the initial assessment and treat- ment are directed toward ensuring that a concentric hip reduction is present. Restoration of hip-joint concentricity may set the stage for profound remodeling. The amount of remodeling that can be relied on to produce a normal acetabulum and the relationship of remodeling and age have been debated. Salter stated that the potential for remod- Pelvic Osteotomies for Hip Dysplasia Journal of the American Academy of Orthopaedic Surgeons 328 Residual Congruent joint Incongruent joint Untreated Developmental dysplasia of the hip Patient aged 8 years or older Patient aged 2-8 years Innominate or Pemberton osteotomy ± proximal femoral osteotomy Triple innominate osteotomy ± proximal femoral osteotomy Triple innominate or periacetabular osteotomy ± proximal femoral osteotomy Patient aged 18 months to 3 years Patient aged 3 years or older Patient aged 2 to 10 years Patient aged 10 to 14 years (open triradiate) Patient aged 14 years or older (closed triradiate) Consider innominate osteotomy Shelf procedure, Chiari osteotomy, or hip fusion ± Femoral derotational osteotomy Femoral derotational and shortening osteotomy Open reduction and capsulorrhaphy Innominate osteotomy Fig. 2 Algorithm for treatment of developmental dysplasia of the hip. eling was greatest at birth and gradually decreased until age 18 months, when it would no longer be ensured. 20 Harris 5 concluded, on the basis of a prospective radiologic study of 79 dislocated hips, that the critical point beyond which restora- tion of hip congruence would not necessarily result in a normal ace- tabulum was age 4; the risk of pro- ducing a moderately or severely dysplastic acetabulum more than doubled if hip reduction occurred beyond this age. Thus, in the 18- month-old to 3-year-old child with acetabular dysplasia due to hip dis- location, the need for an acetabular procedure at the time of open re- duction and capsulorrhaphy is con- troversial. One approach is to delay a secondary procedure so that the adequacy of the acetabular remodeling response can be as- sessed. 21 Most North American centers, however, are moving toward following SalterÕs advice to include the acetabular procedure at the time of primary treatment in order to maximize the likelihood that a normal acetabulum will ulti- mately develop. 20,22 DelBello et al 22 compared the re- sults of open reduction alone, open reduction followed by delayed innominate osteotomy, and open reduction plus immediate innomi- nate osteotomy in a group of older children with DDH. Only the im- mediate osteotomy group achieved acetabular indices comparable to those in normal control subjects. In addition, the hips of 95% of the patients in the immediate innomi- nate osteotomy group were classi- fied as group I or II on the Severin hip dysplasia scale, compared with 61% in the group of patients who underwent open reduction alone and 60% in the delayed innominate osteotomy group. No differences were found in the rate of osteo- necrosis of the femoral head, the estimated surgical blood loss, and the operative time. On the basis of these findings, the authors recom- mended routine innominate oste- otomy at the time of open reduc- tion for all patients over the age of 18 months. In the child aged 3 years or older, innominate osteotomy is per- formed routinely because of the unpredictable remodeling potential beyond this age. 23 In the patient older than age 8, the treatment plan is based on the symptoms and the severity of the residual dysplasia. In terms of clinical characteristics, patients with DDH vary greatly, ranging from the asymptomatic patient in whom the dysplasia is an incidental finding to the severely incapacitated individual who is in constant pain. Nonoperative therapy is directed toward minimizing excessive point loading across the joint by avoiding unnecessary impact-loading activi- ties, achieving ideal body weight, and maintaining overall physical fitness and muscle tone. This can be supplemented by judicious use of nonsteroidal anti-inflammatory agents in patients for whom they are not contraindicated. While this can be an effective means of treat- ing the symptoms, this strategy does not address the underlying malalignment that is the ultimate cause of osteoarthritis. It is impor- tant that parents and older patients understand this, particularly when there are few, if any, symptoms. Paradoxically, these are the pa- tients who may have the most to gain from surgery. The goal and type of surgery chosen depend on the severity of the patientÕs condition. In general, there are two groups of patients with residual dysplasia. 24 The group amenable to Òreconstruc- tiveÓ procedures are minimally symptomatic and have normal joint congruence and no irreversible car- tilage injury. The goal of surgery in this setting is realignment of the joint surfaces to produce more nor- mal loading and to forestall the development of osteoarthritis. Reconstructive osteotomies include Salter, Pemberton, triple innomi- nate, and periacetabular proce- dures. 20,25-27 These procedures have a relatively predictable outcome. In contrast, the ÒsalvageÓ group demonstrate evidence of irreversible cartilage injury. In this setting, the goal of surgery is to relieve pain, delay the inevitable arthroplasty, and improve function in the mean- time. The procedures used have a less certain outcome. Examples in- clude Chiari 28 and shelf procedures, often performed on an incongruent, already distorted hip joint. Primary Treatment of Complete Hip Dislocation If closed treatment has not been effective in a child less than 18 months of age, establishment of normal hip alignment can gener- ally be achieved by open reduc- tion and capsulorrhaphy alone. In patients between 18 months and 3 years of age, immediate in- nominate osteotomy at the time of open reduction maximizes the remodeling potential of the hip. In the presence of excessive fe- moral anteversion or valgus of the femoral neck, a varus derota- tional osteotomy can be included (Fig. 3). We do not advocate the Pember- ton or Dega procedure as part of the treatment for primary dislocation of the hip because both either decrease acetabular volume or change ace- tabular shape. The Salter procedure allows redirection but avoids shape or volume changes. For the child over age 3 years with untreated DDH, the approach is similar. The only difference is the addition of a derotational femoral shortening osteotomy to decrease the compressive forces on the fe- moral head after reduction. CDR Bruce L. Gillingham, MC, USN, et al Vol 7, No 5, September/October 1999 329 Treatment of Residual Dysplasia Treatment of residual dysplasia is based on the patientÕs age and the presence or absence of congruent hip reduction. In the child between the ages of 2 and 10 with a well- reduced hip with anterolateral acetabular deficiency of a moderate degree, either a Salter or a Pember- ton procedure can be performed. Theoretically, with the Pemberton procedure, the relative relationship of the cuts in the inner and outer tables of the ilium can be adjusted to change the location of the de- sired augmentation. As a configu- ration-changing osteotomy, the Pemberton is particularly helpful in the case of a shallow, capacious, or ÒwanderingÓ acetabulum. Although many cogent argu- ments have been made regarding the relative usefulness of the Salter and Pemberton procedures, there is little objective basis for choosing one over the other. The Pemberton procedure has the advantage that because the osteotomy is so secure, fixation pins are not required, and a second operation to remove pins is unnecessary. If severe coxa valga or anteversion is present, a femoral osteotomy may have to be added to achieve an anatomically correct radiographic appearance. In the older child or adolescent in whom the triradiate cartilage remains open (usually over age 10), the triple innominate osteoto- my 26 is our procedure of choice. Although a more extensive dissec- tion is required, this procedure offers the advantage of increased acetabular fragment mobility and thus a wider range of coverage options. After triradiate cartilage closure, the periacetabular osteotomy pop- ularized by Ganz et al 27 can be con- sidered in addition to a triple oste- otomy. The Ganz procedure is technically challenging, but it af- fords nearly unlimited acetabular mobility. In the patient between 2 and 8 years of age with an incongruent joint, a Salter or Pemberton inno- minate osteotomy can be consid- ered provided sufficient remodel- ing potential is present. However, the outcome is less predictable than in the child less than age 4 with concentric reduction. In such cir- cumstances, a femoral osteotomy is commonly added to decompress the joint. Beyond age 8, when no remodeling will occur, a salvage osteotomy, such as a Chiari or shelf procedure, is necessary. 28,29 Redirectional (Complete) Osteotomies As their name implies, redirectional osteotomies improve the coverage of the femoral head by shifting the position of the acetabulum. The acetabulum itself remains un- changed. Because these procedures involve complete cuts through the innominate bone, fixation is re- quired to maintain the new align- ment until the osteotomy heals. In general, there is a direct relation- ship between the technical com- plexity of a redirectional osteotomy and the amount and range of cover- age possible. Single Innominate Osteotomy (Salter) First described by Salter in 1961, 20 the single innominate osteotomy Pelvic Osteotomies for Hip Dysplasia Journal of the American Academy of Orthopaedic Surgeons 330 A B Fig. 3 Bilateral DDH in a 2-year-old girl. A, Preoperative AP radiograph of the pelvis. B, AP radiograph obtained after staged bilateral open reductions, proximal femoral varus osteotomies, and innominate osteotomies. Ideal graft position is present on the left; undesirable slightly posterior displacement of the osteotomy is present on the right. remains in widespread use (Fig. 4). Salter conceptualized that acetabu- lar maldirection was responsible for the deficiency of femoral head coverage and designed an osteotomy to redirect the acetabulum and thereby provide a stable hip reduc- tion in the functional weight-bearing position. The amount of acetabular fragment mobility obtained with the single innominate osteotomy depends on rotation and hinging through the pliable fulcrum of the pubic symphysis. The primary indication for a Salter osteotomy is a deficiency of anterolateral femoral head coverage in an otherwise concentrically re- duced hip. A shallow acetabulum is a relative contraindication. Im- provement in the center-edge angle of 20 to 22 degrees and a 10-degree improvement in the acetabular index can be expected. 30,31 Skillful exposure and clearing of the sciatic notch is critical. The Gigli saw cut begins low in the sci- atic notch and exits just above the anterior inferior iliac spine. The inferior fragment is pulled distally and anteriorly with a towel clamp to provide increased anterolateral coverage. Care should be taken to prevent displacing the proximal fragment, as this will lead to open- ing of the osteotomy posteriorly at the sciatic notch, resulting primarily in leg lengthening. Mobility of the fragment is enhanced by placing the ipsilateral leg into the figure-of-four position of hip flexion, abduction, and external rotation. A triangular wedge of anterior iliac crest is fixed into place at the osteotomy site with two threaded pins directed posteromedially. These are subse- quently removed at 6 to 8 weeks in young children and at 3 to 4 months in older children, who are at a greater risk for graft collapse. An iliopsoas tenotomy at the pelvic brim is considered an essential com- ponent of the procedure to both de- crease compression on the femoral head and allow distal fragment mo- bility. In a review of the 15-year data on 140 patients treated primarily for hip dislocation and subluxation, Salter and Dubos 32 reported 93.6% excellent or good results in patients aged 18 months to 4 years, with no failures. In the 4- to 10-year-old age group, however, only 56.7% had good or excellent results, and the failure rate was 6.6%. Initial operative complications included superficial wound infections (inci- dence of 1.5%), femoral head osteo- necrosis (5.7%), loss of osteotomy position prior to the use of two pins (2.8%), redislocation (5.6%), resubluxation (14.3%), and supra- condylar femur fracture (6.4%). There were no deep infections. Therefore, because less satisfactory results generally occur in older children, triple innominate osteot- omy is preferable for children over age 10. Triple Innominate Osteotomy The triple osteotomy described by Steel 26 in 1965 consists of oste- otomies of the ischium and pubis in addition to a Salter innominate osteotomy (Fig. 5). Tšnnis et al 33 have described a modification of the triple osteotomy that is also widely used. The triple osteotomy is generally indicated for older children and adolescents, in whom symphyseal rotation is more limited than in younger children due to skeletal maturity and decreased ligamentous laxity (Fig. 6). As is the case with the single innomi- nate osteotomy, concentric hip re- duction is a prerequisite. Because it is a circumacetabular osteotomy, significant mobility of the acetabu- lar fragment is possible. In addi- tion, if the ischial osteotomy is directed obliquely from lateral to medial, the acetabular fragment can be displaced medially, moving the hip center to a more physio- logic position and improving gait mechanics. The triple osteotomy requires two incisions. Steel 26 originally ad- vised a horizontal incision made over the ischial tuberosity for the ischial osteotomy and an anterior incision (as in the single innominate procedure) for the pubic and in- nominate osteotomies. We now prefer to make the Salter cut only through the anterolateral incision and to make the superior pubic CDR Bruce L. Gillingham, MC, USN, et al Vol 7, No 5, September/October 1999 331 Fig. 4 Salter single innominate osteotomy. Fig. 5 Triple innominate osteotomy. ramus and ischial cuts through a single transverse groin incision. Placement of bone graft and fixa- tion are performed as for the Salter osteotomy. Care must be taken to avoid excessive external rotation of the free distal fragment. Also, mus- cle should not intervene in the pubic and ischial cuts, as pseudar- throsis can occur. Use of a tempo- rary Schanz screw to guide the ace- tabular segment allows appropriate acetabular redirection, avoiding excessive external rotation. In SteelÕs original series, 26 the results were considered to be satis- factory in 19 of the 23 hips with congenital dysplasia followed up between 2 and 10 years postopera- tively. Five complications were reported: two cases of postopera- tive ileus, one ischial wound infec- tion (Escherichia coli), and two instances of pressure necrosis of the skin over the anterior inferior spine of the displaced acetabular fragment. In a review of 44 patients (56 hips) an average of 7 years after triple osteotomy, Faciszewski et al 34 reported improvement in both pain and function in 94% of pa- tients. The center-edge angle in- creased by a mean of 33 degrees, and the acetabular angle decreased by a mean of 15 degrees. Two com- plications occurred: one pulmo- nary embolism and one superficial wound infection. Periacetabular Osteotomy Introduced in 1988 by Ganz et al, 27 the periacetabular osteotomy allows extensive acetabular reori- entation, including medial and lat- eral displacement. Osteotomies are performed in the pubis, ilium, and ischium. A vertical posterior- column osteotomy connects the posterior extremes of the iliac and ischial osteotomies approximately 1 cm anterior to the sciatic notch (Fig. 7). This osteotomy must be done after skeletal maturity, be- cause it crosses the triradiate carti- lage; therefore, it is indicated only for older adolescent and adult pa- tients with dysplastic hips that re- quire improvement of congruency and containment (Fig. 8). Because no complete cut is made into the sciatic notch (the posterior column is split vertically), the Ganz procedure is very stable, and no postoperative cast is required. Im- mediate crutch weight bearing is advised. Additional advantages include preservation of the blood supply to the acetabular fragment, use of a single surgical approach, and preservation of the shape of the pelvis, which permits normal vaginal delivery. A disadvantage Pelvic Osteotomies for Hip Dysplasia Journal of the American Academy of Orthopaedic Surgeons 332 A B C D Fig. 6 Images of a female patient with left acetabular dysplasia (same patient as in Fig. 1). A, At age 18, AP radiograph of the abducted, internally rotated left hip shows joint congruence. B, AP view obtained at age 19, 1 1 Ú2 years after left proximal femoral varus osteotomy. C, Three-dimensional reconstruction of a CT study of the hip obtained at age 21 demonstrates persistent left acetabular dysplasia with deficient anterolateral coverage. D, AP radiograph obtained after triple innominate osteotomy on the left shows improved coverage. Fig. 7 Ganz periacetabular osteotomy. is that the procedure is difficult to learn. In 1995, Trousdale et al 35 reported the results of use of the Ganz peri- acetabular osteotomy, with or without intertrochanteric osteot- omy, on 42 patients with dysplas- tic, osteoarthritic hips. The aver- age follow-up interval was 4 years. They found that the Harris hip score improved from an average of 62 points preoperatively to 86 points postoperatively (P<0.0001). The average anterior-edge angle was 1 degree preoperatively and 27 degrees postoperatively. Com- plications included deep venous thrombosis in 2 patients, pubic nonunion in 2, and heterotopic bone formation in 14. There were no major neurovascular complica- tions in this series, although nerve and/or vessel injury is possible with this rather complex oste- otomy. Reshaping (Incomplete) Osteotomies The object of reshaping osteoto- mies is restoration of acetabular morphology by changing the shape of the acetabulum. They are pri- marily indicated for the patient with a capacious or wandering acetabulum, as is commonly seen in both childhood DDH and cere- bral palsy. Depending on the os- teotomy, additional lateral and/or posterior coverage can be obtained. They should be used only in the skeletally immature, as the osteot- omy hinges through the triradiate cartilage. Because the osteotomy is incomplete, there is inherent stabil- ity after graft placement, and inter- nal fixation is not required. Pemberton Osteotomy In 1965, Pemberton 25 described an incomplete osteotomy that hinges through the triradiate carti- lage (Fig. 9). A Smith-Peterson approach is used to expose the in- ner and outer tables of the ilium. The outer ilium is osteotomized beginning immediately superior to the anterior inferior iliac spine. The osteotomy extends posteriorly 0.25 inch above and parallel to the joint capsule and is carried to the ilioischial limb of the triradiate car- tilage. The inner ilium is osteoto- mized separately to match the outer cut (if anterior coverage is primarily desired); alternatively, the posterior limb may be shifted anteriorly to provide additional lat- eral coverage. Care must be taken to remain halfway between the anterior edge of the sciatic notch and the posterior rim of the acetab- ulum. The osteotomy is opened enough to create an acetabular angle of approximately 0 degrees. A groove is created to hold the graft in posi- tion, and a triangular wedge of bone from the anterior ilium is placed and impacted. No internal fixation is required. A spica cast is used for 8 weeks. This osteotomy is appropriate for patients between the age of 18 months and skeletal maturity (Fig. 10). In PembertonÕs original series of 91 patients (115 hips), all 46 chil- dren less than 4 years of age had a good result. 25 There were 20 good and 4 fair results in children aged 4 to 7 years, and 12 good, 6 fair, and 3 poor results in children between the ages of 7 and 12 years. Com- CDR Bruce L. Gillingham, MC, USN, et al Vol 7, No 5, September/October 1999 333 A B C Fig. 8 Images of a 15-year-old girl with left acetabular dysplasia. A, Preoperative AP radiograph of the pelvis. B, Three-dimensional CT reconstruction shows significant uncovering of the left hip. C, AP radiograph obtained after a Ganz periacetabular osteotomy. Fig. 9 Pemberton osteotomy. plications included 5 redisloca- tions, 12 cases of osteonecrosis (all eventually healed), and 2 sciatic nerve palsies (in cases of high dis- location). Faciszewski et al 36 reported the results in 52 hips with acetabular dysplasia treated with the Pember- ton osteotomy. The average age of the 42 patients was 4 years at the time of surgery. The mean follow- up interval was 10 years. At the time of follow-up, 42 hips (81%) were radiographically normal. No patient had pain, three patients had decreased range of motion, and one patient had a positive Trendelen- burg test. There were no complica- tions. Dega Osteotomy The Dega osteotomy is an ace- tabuloplasty that also changes ace- tabular configuration and shape. It provides increased posterolater- al coverage by means of an osteot- omy of the lateral cortex of the ilium only, hinging through the open triradiate cartilage. 37 The primary indication for this osteot- omy is the presence of a capacious acetabulum with posterolateral deficiency, as is often found in children with cerebral palsy. Some authors also use it for persis- tent acetabular dysplasia in DDH. The technique has been well de- scribed by Mubarak et al. 37 Salvage/Augmentation Procedures A salvage osteotomy may be indi- cated when a congruent reduction between the femoral head and the acetabulum cannot be obtained. Such an osteotomy may also be appropriate for an adolescent or adult with a painful subluxated hip or for a patient with prior surgical failures. Selection of one of the var- ious salvage/augmentation proce- dures presupposes that the remain- ing hyaline cartilage is inadequate or cannot be redirected to provide coverage of the femoral head. These procedures act to increase the weight-bearing surface and rely on capsular metaplasia to provide an articulating surface. Commonly, an associated valgus or varus osteoto- my will help to realign the joint and decompress the joint. Chiari Osteotomy The primary indication for use of the Chiari osteotomy is a painful, subluxated hip without the possi- Pelvic Osteotomies for Hip Dysplasia Journal of the American Academy of Orthopaedic Surgeons 334 A B C D Fig. 10 Images of a girl with bilateral acetabular dysplasia. A, At 3 years of age, AP radiograph of the pelvis showed bilateral dysplasia. B, At 7 1 Ú2 years of age, three-dimensional reconstruction of a CT study of the pelvis showed persistent dysplasia. C, Radiograph of the right hip obtained during a Pemberton osteotomy. D, Anteroposterior radiograph of the pelvis obtained 2 months after bilateral Pemberton osteotomies shows graft incorporation and improved coverage. . competence and resistance to fatigue of the hip abductors. The range of hip motion is carefully documented, with particular atten- tion paid to hip rotation and the presence of contractures. Pain with