➢ Legg-Calvé-Perthes disease is a childhood hip condition in which the blood supply to the capital femoral epiphysis is interrupted, causing osteonecrosis and chondronecrosis that lead to progressive deformity of the femoral head and secondary degenerative osteoarthritis in later life.
➢ The etiology of Legg-Calvé-Perthes disease remains unclear, with both biological and mechanical factors playing important roles in the pathogenesis of the condition.
➢ The treatment of Legg-Calvé-Perthes disease remains controversial but is dependent on several salient factors, including the age at clinical onset, the extent of epiphyseal involvement, the stage of the disease, and the degree of femoral head deformity.
➢ The literature supports operative containment treatment in the early stage of disease. Such treatment has led to improved femoral head sphericity with better patient outcomes in multicenter prospective cohort studies.
➢ The number of hips that need to be treated operatively in order to achieve a modest treatment effect remains high. Multicenter prospective cohort studies have shown that 6 to 7 patients need to be managed to create 1 spherical femoral head that would not have otherwise occurred.
Over a century ago, Arthur Legg1, Jacque Calvé2, and Georg Perthes3 reported similar accounts of a childhood hip condition, with all 3 surgeons postulating a different etiology. Today, the condition Legg-Calvé-Perthes (LCP) disease refers to idiopathic osteonecrosis of the capital femoral epiphysis and continues to be one of the most common causes of permanent femoral head deformity in childhood4,5. The goal of treatment of LCP disease is to minimize femoral head deformity and consequently to reduce the risk of secondary degenerative osteoarthritis in later life6-8. Although many aspects of the condition have been studied, leading to better understanding of the pathogenesis and natural history, the condition remains challenging, with ongoing debate and no established consensus about etiology and treatment.
The clinical onset of LCP disease usually occurs in children between the ages of 4 and 8 years, with the disease presenting at an older age in children from India9. The reported incidence of LCP disease varies from 4 to 32 per 100,000, with the condition being 5 times more common in males than females10. The incidence of LCP disease differs between countries and is dependent on race. There is substantial ethnic variation, with Caucasians being more affected than East Asian and African American counterparts11,12. In addition to racial differences, latitude has an influence on the susceptibility to LCP disease, with the incidence being lowest in equatorial regions and increasing with latitude13. The incidence also varies depending on socioeconomic class, with the incidence being higher in less densely populated areas and in lower socioeconomic classes11,14-16.
Numerous theories about the etiology of LCP disease have been suggested, but none have been validated conclusively and the cause remains unclear. The predominant opinion is that LCP disease is multifactorial and is caused by a combination of genetic and environmental factors. A possible explanation is that genetic factors confer susceptibility to the disruption of the blood supply to the capital femoral epiphysis and that environmental factors such as repeated subclinical trauma resulting from hyperactivity or mechanical overload trigger the disease. Other factors associated with the etiology of LCP disease include an increased association with maternal smoking and passive smoking17,18.
The pathogenesis of osteonecrosis is becoming better understood. The deficiency of clinical samples has encouraged the use of alternate methods to investigate the pathogenesis of LCP disease. It is not clearly known whether a single episode or multiple episodes of infarction are required to produce LCP disease as a single episode does not produce femoral head deformity and histological characteristics of LCP disease in canines19,20. Hence, the multiple-infarction theory was proposed on the basis of findings observed following a second episode, leading to the conclusion that LCP disease may be due to more than one episode of infarction19,20. In contrast, Kim et al. reported that a single infarction event produced femoral head deformity and histological changes similar to LCP disease in a piglet model of osteonecrosis21.
In the study by Inoue et al., femoral head biopsy specimens from patients with LCP disease revealed dead woven bone superimposed on dead lamellar bone, with the marrow space occupied with dead granulation tissue22. Similarly, in three other studies, core biopsy and whole femoral head specimens from patients with LCP disease displayed multiple layers of cement lines with thickened trabeculae, suggesting that multiple episodes of infarction are essential to produce LCP disease23,24 or that a single infarction event with subsequent mechanical loading that further injures and/or compresses the vessels during the repair process produces secondary episodes of infarction25.
Selective angiography26-28, bone scintigraphy29, and contrast-enhanced magnetic resonance imaging (MRI)30 support the concept that the key pathological event associated with the initiation of the development of LCP disease is disruption of the blood supply to the capital femoral epiphysis. Selective angiography has demonstrated disruption of the lateral epiphyseal artery at its origin in 68% of patients with LCP disease in all stages of the disease26.
The pathological progression of the disease affects the articular cartilage, epiphysis, physis, and metaphysis. In the affected region, the trabecular bone and the marrow space within are necrotic. Osteoclastic bone resorption is the principal repair response after revascularization. In the area of bone resorption, appositional new bone formation is not observed while these areas are being replaced with fibrovascular tissue. The changes induced by the ischemia produce a necrotic femoral head with decreased mechanical stiffness31,32. Microfractures in the bone are known to be caused by repetitive loading and are normally repaired by bone cells33. However, no cells are available to detect and repair the microdamage related to repetitive loading in necrotic bone. Furthermore, the mechanical properties of the femoral head are further compromised with the invasion of fibrovascular tissue and osteoclastic resorption of the necrotic bone31.
The concomitant role of repetitive loading in increasing deformity has been demonstrated in the hypertensive rat, which has a predilection for femoral head osteonecrosis resembling LCP disease34. Patients with LCP disease also tend to have delayed bone age4 and smaller femoral ossific nuclei. The relatively larger cartilaginous component of the epiphysis in such patients renders the traversing blood vessels more vulnerable to mechanical compression35. Hence, with this vicious cycle of ischemia, decreased mechanical properties of the femoral head, and joint loading, it remains unclear what factors determine the healing and the remodeling potential of the femoral head in patients with LCP disease.
Imaging and Classification
Radiographs remain the mainstay imaging modality for the diagnosis and surveillance of LCP disease. Waldenström described 4 radiographic stages of LCP disease that occur over a two-year period: the initial stage, the fragmentation stage, the reossification stage, and the healed stage (Fig. 1)36. Joseph et al.37 modified the Waldenström classification system by further classifying each of the first 3 stages into early and late substages. The same authors showed that classifying the fragmentation stage into early and late stages had an impact on both treatment decisions and patient outcomes38. More recently, Hyman et al.39 demonstrated that the modified Waldenström classification system of LCP disease had nearly perfect agreement in terms of both intraobserver and interobserver reliability.
Contrast-enhanced MRI can detect LCP disease during the early stages of the condition30. Dynamic contrast-enhanced subtraction MRI has been shown to be more sensitive than radiography, to correlate well with bone scintigraphy, and to provide more specific information about the blood flow to the femoral head for the detection of early ischemia30,40. Furthermore, physeal involvement on MRI scans has been shown to have a prognostic value in cases of LCP disease41. Studies comparing non-contrast-enhanced and contrast-enhanced MRI have shown that contrast-enhanced subtraction MRI better delineates the extent of necrosis of the femoral head in the initial stage of LCP disease42. In addition to the advantages of contrast-enhanced MRI, measurements of perfusion (the MRI perfusion index) obtained from contrast-enhanced subtraction MRI in the early stages of LCP disease (Fig. 2) have been shown to correlate well with femoral head deformity as measured on radiographs after a minimum of two years of follow-up, with high interobserver reliability43.
In 1992, Herring et al. described the lateral pillar classification system (Table I)44. This system was based on the radiographic evaluation of 93 hips (86 patients) that were followed to skeletal maturity. The classification of each hip at each follow-up was determined on the basis of an anteroposterior radiograph. The lateral pillar classification system is applied during the fragmentation stage of the disease when substantial femoral head deformity has occurred. Hence, the clinical applicability has been hampered by the need to wait until the fragmentation phase.
A recent study demonstrated that perfusion MRI measurements of the entire femoral epiphysis and the lateral third of the femoral epiphysis in the early stages of LCP disease were predictive of lateral pillar involvement at the maximum fragmentation phase. Kim et al.45 observed a significantly (p ≤ 0.001) greater percent perfusion of the entire epiphysis and its lateral third in femoral heads that developed group-A lateral pillar involvement as compared with those that developed group-B or C involvement. Hence, the “wait to classify” approach using radiographs to distinguish patients with a good or poor prognosis at the early stage of LCP disease might become obsolete with the introduction of perfusion MRI measurement of the femoral epiphysis.
Stulberg et al. proposed a radiographic outcome classification system for LCP disease that has become the most commonly used system7. This system was based on 2 groups of patients with LCP disease who were followed for more than 30 years. The 5 Stulberg classes are based on the shape and size of the femoral head, the shape and dimension of the acetabulum, and the congruency between the femoral head and the acetabulum at skeletal maturity. The Stulberg classification system is not entirely satisfactory as its reliability is variable and is dependent on the experience of the observer46,47. Reliability among observers improved when the classification system was modified to 3 categories5. Shah et al.48 devised a reliable quantitative measure for evaluating the radiographic outcomes for skeletally mature patients with LCP disease. The shape and size of the femoral head and the femur-acetabulum relationship were quantified with use of a sphericity deviation score that distinguished between good outcomes (Stulberg classes I and II) and poor outcomes (Stulberg classes III, IV, and V).
Larson et al.49 assessed a cohort of patients from the original multicenter prospective study by Herring et al.4 in order to document the natural history of LCP disease 20 years after nonoperative treatment. That study questioned the validity of defining Stulberg class-III hips as fair results; whereas patients with Stulberg class-I and II hips had relatively low rates of secondary degenerative osteoarthritis at the time of follow-up, the rates were identically high in patients with Stulberg class-III hips as in those with Stulberg class-IV and V hips. Thus, it appears that only spherical femoral heads provide stability and that the previous assumption that Stulberg class-III hips represent a fair outcome is open to question (Table II).
Natural History and Prognosis
LCP disease is a self-healing condition in which the blood supply to the capital femoral epiphysis spontaneously recovers through 1 of 2 mechanisms. These mechanisms involve either a rapid recanalization of existing vessels that occurs within weeks or the formation of new vessels (neovascularization) over a period of months to years29.
The prognosis of the hip joint affected by LCP disease depends on the age of the patient at the time of onset, the stage of the disease, the extent of epiphyseal involvement, and the lateral extrusion of the femoral head7,50,51. Patients in whom the disease presents before the age of 5 to 7 years have been found to have a substantially better outcome than those in whom it presents after 8 to 9 years4,5,8,52-55. Late-presenting LCP disease in adolescent patients has been associated with poor results37,56.
Girls have been found to have a worse prognosis compared with boys57,58. Other clinical features, such as a heavy patient, stiffness with progressive loss of hip range of motion, adduction contracture, and a longer duration from onset to completion of the healing phase, have been associated with a poor prognosis59,60. Predicting the outcome at an early stage of the disease, before the development of substantial femoral head deformity, remains a clinical challenge61,62.
The shape of the femoral head plays an essential role in the prognosis of the hip joint during the natural history of LCP disease63-66. The choice between operative and nonoperative treatment is based on the concept of containment. Containment involves maintaining the femoral head within the acetabulum throughout the entire evolution of the disease, thereby protecting the vulnerable segment of the epiphysis from being subjected to deforming forces67-69. The concept of containment is based on the principle that a deformed epiphysis is completely placed within the acetabulum and a round acetabulum makes the femoral head more spherical.
Early nonoperative treatment of LCP disease focused on prolonged periods of hospitalization with complete non-weight-bearing with either bed rest or the use of a wheelchair. Harrison et al.70 emphasized the efficacy of the concept of containment with use of an abduction plaster cast known as the broomstick plaster. Petrie and Bitenc popularized abduction casting with weight-bearing71. Removable braces that mimic Petrie casts such as the Atlanta and Toronto braces have replaced abduction casting. Other modalities of nonoperative treatment include observation and range-of-motion exercises (Fig. 3).
Non-weight-bearing of the affected limb with use of crutches is one of the commonly recommended nonoperative treatments for LCP disease and remains controversial72-74. Clinical studies of non-weight-bearing for the treatment of LCP disease have shown conflicting results, with some studies suggesting a beneficial effect in association with prolonged bed rest75 and spica cast immobilization76,77 and others showing no beneficial effect72.
In an animal model study involving piglets78, local non-weight-bearing decreased femoral head deformity following ischemic osteonecrosis despite the mechanical weakening of the femoral head. Furthermore, local non-weight-bearing produced greater revascularization of the necrotic femoral head, but with increased osteoclast-mediated bone resorption. Critically, this increased bone resorption was not coupled with increased bone formation. In another study involving the same piglet model of ischemic osteonecrosis, bone morphogenetic protein (BMP)-2 with bisphosphonates decreased bone resorption and increased new bone formation during non-weight-bearing treatment79. Additional work on translating these findings is required.
In 1971, the Scottish Rite Hospital in Atlanta introduced an ambulatory abduction orthosis that was mobile, lighter, and designed to contain the femoral head in the acetabulum and to allow remodeling without limiting activities80. Several other orthoses, including the Toronto and Newington braces81,82, were developed around the same time. Two studies of orthotic treatment with the Atlanta brace showed no benefit over observation and range-of-motion exercises of the hip80,83. Therefore, the current evidence in the literature does not support the use of orthoses for the treatment of LCP disease.
More recently, Rich and Schoenecker84, in an uncontrolled study of 240 hips that were treated with an A-frame orthosis and range-of-motion exercises, reported that 190 hips (79%) were classified as Stulberg class I or II, including 39 (76%) of 51 hips in patients over the age of 8 years.
Bisphosphonate Therapy and Anabolic Agents
Bisphosphonates are synthetic analogs of pyrophosphate that bind with high affinity to hydroxyapatite in vascularized areas. Their access to nonvascularized regions of the femoral head is limited. Bisphosphonates have the potential to decrease bone resorption by limiting osteoclastogenesis and have been shown to delay the resorption of necrotic bone and to decrease femoral head deformity in animal models of LCP disease. Bisphosphonate therapy has been used to treat patients with LCP disease with the maintenance of Z scores, but its application in clinical use is unproven85,86. Other anabolic agents such as osteoprotegerin-immunoglobulin Fc segment complex (OPG-Fc) that inhibit RANKL (receptor activator of nuclear factor kappa-B ligand) also have been shown to eliminate osteoclastogenesis and to preserve the femoral heads of piglets with ischemic osteonecrosis87. The use of BMPs to treat LCP disease is experimental, and additional studies are required prior to clinical use. However, in a piglet model of ischemic osteonecrosis, combined treatment with bisphosphonate and BMP-2, administered by means of local intraosseous injection, was associated with a significantly greater percentage of osteoclasts on trabecular bone (p < 0.0001), greater bone volume, and remodeling of the necrotic femoral head88.
Containment can be achieved by means of an osteotomy of the femur and/or pelvis. Soeure and De Racker first introduced the concept of operative containment of the femoral head via femoral varus osteotomy in 195289. A pelvic osteotomy reorients the acetabulum such that it covers the anterolateral part of the femoral epiphysis or creates an osseous shelf over the extruded part of the epiphysis. In 1962, Salter added the innominate osteotomy as a method of containment for the treatment of LCP disease90.
Femoral and Pelvic Osteotomies
Proximal femoral varus osteotomy is one of the most widely used operative procedures for the treatment of LCP disease (Fig. 4). Joseph et al.38 analyzed the outcomes of femoral varus osteotomy in a study of 97 patients with LCP disease and concluded that containment surgery aimed at preventing femoral head deformity should be performed before the advanced stage of fragmentation. Other studies have demonstrated similar results, with better femoral head sphericity, when surgery was performed at an early stage38,91-94.
The 2 largest multicenter prospective cohort studies of which we are aware showed that proximal varus femoral osteotomy produced radiographic outcomes that were superior to those achieved following nonoperative treatment4,5. Those 2 studies collectively represent the best data available on operative treatment (Tables III and IV). In the study by Herring et al.4, all hips were classified with the lateral pillar and Stulberg classification systems after operative treatment. The retrospective application of the lateral pillar classification raises controversy about treatment recommendations based on the classification95,96. Furthermore, operative treatments were rendered in the initial stage of LCP disease in >90% of the patients in the study by Herring et al.4. There were no differences between hips that were treated with a femoral varus osteotomy and those that were treated with a Salter innominate osteotomy. Younger patients (those with a chronological age of <8 years or a skeletal age of <6 years) showed no significant benefit from any type of surgery. In the lateral pillar B group, the outcomes of operative treatment were superior in patients who were >8 years of age at the time of onset. Older patients in the B/C border group also benefited, but only in terms of fewer Stulberg class-IV and V results; there were no increases in the number of spherical (Stulberg class-I and II) hips in the B/C border group. Patients in the lateral pillar group C had the least favorable outcomes, with no differences between the operative and nonoperative groups. In the study by Wiig et al.5, patients who were 6 years of age at diagnosis and had >50% femoral head necrosis had substantially better outcomes after proximal femoral varus osteotomy than after treatment with an orthosis or physiotherapy. The authors found no differences in outcomes after any of the treatments in patients under the age of 6 years. The authors recommended proximal femoral varus osteotomy in patients with an age of ≥6 years at the time of diagnosis and >50% femoral head necrosis and concluded that abduction orthoses should be abandoned for the treatment of LCP disease.
The 3 factors related to the Stulberg radiographic outcome in those 2 multicenter prospective cohort studies included the age at the time of onset of LCP disease, the lateral pillar classification, and the method of treatment (operative or nonoperative)4,5. However, if one analyzes the data from the studies by Herring et al.4 and Wiig et al.5 and assumes that operative treatment is performed early (before radiographic classification is possible), then the results do not appear to be as good in terms of the number needed to treat. As noted previously, Larson et al.49 showed that only spherical (Stulberg class-I and II) femoral heads had a low rate of secondary degenerative osteoarthritis at the time of the 20-year follow-up, with identically high rates in Stulberg class-III hips and Stulberg class-IV and V hips following nonoperative treatment. However, one cannot assume similar rates of secondary degenerative osteoarthritis in operatively managed patients with Stulberg class-III, IV, and V hips. Nevertheless, in terms of the prevention of secondary degenerative osteoarthritis, it could be argued that one should only consider a spherical femoral head as a worthwhile outcome result. In both the studies of Herring et al.4 and Wiig et al.5, the Stulberg classification is modified and data are presented for spherical heads (Stulberg I and II), ovoid heads (Stulberg III), and flat heads (Stulberg IV and V). In the study by Herring et al.4, surgical treatment resulted in a 17% increase in the number of spherical femoral heads as compared with nonoperative treatment for all patients with an age of >8 years. Similarly, in the study by Wiig et al.5, there was a 14% increase in the number of spherical femoral heads in patients with an age of >6 years. Therefore, the number needed to treat can be calculated as 6 for the study by Herring et al.4 and as 7 for the study by Wiig et al.5; i.e., only 1 in every 6 or 7 procedures will result in a spherical femoral head that would not have occurred without surgery. This increase in the number of spherical femoral heads is statistically significant when groups are compared. Taken together, these studies show that current operative treatments have a relatively modest treatment effect, and more research is required to develop more effective therapies for LCP disease in the future.
Two meta-analyses of available data in the literature have been undertaken with use of radiographic femoral head sphericity at skeletal maturity as the primary outcome97,98. A spherical femoral head was represented by Stulberg classes I and II, and an aspherical head was represented by Stulberg classes III, IV, and V. Nguyen et al.97 found no difference between operative and nonoperative treatment when variables such as age, sex, and disease severity were not considered. However, after adjustment for disease severity, operative treatment was twice as likely (odds ratio [OR], 1.75; 95% confidence interval [CI], 1.30 to 2.37) to produce a spherical congruent femoral head than nonoperative treatment among patients 6 years of age or older, with similarly good outcomes in younger patients with or without surgery. The meta-analysis was based on 23 studies; 22 were retrospective and 1 was prospective, with high heterogeneity across the studies. Saran et al., in a meta-analysis of 14 nonrandomized studies (including 12 Level-III and 2 Level-II studies), investigated whether a femoral varus osteotomy or Salter innominate osteotomy resulted in improved radiographic femoral head sphericity at the end of the disease process compared with nonoperative treatment98. A spherical femoral head at skeletal maturity appeared more likely to be associated with operative treatment than nonoperative treatment in patients with LCP disease when all of the data were pooled without stratification for risk factors such as the age at onset or the stage of disease (OR, 1.29; 95% CI, 1.05 to 1.60). However, this improvement was relatively small, with a 30% greater chance of a good result after operative treatment. Stratification by the age of the patient or the stage of disease at the time of surgery was not possible in all of the studies. Subgroup analyses performed on the basis of age suggested that patients older than 6 years have a higher likelihood of femoral head sphericity when treated operatively during or before the fragmentation phase, with no effect on patients younger than 6 years age and with patients 6 to 8 years of age representing a transitional group in which the role of surgery is less obvious.
In the late stages of LCP disease, some patients develop reduced range of motion of the hip, particularly abduction, with attempted abduction resulting in hinging and pain99, and the hip may remain “noncontainable.” This impingement of the extruded epiphyseal segment of the deformed femoral head is the likely cause of such hinge abduction100,101. The restoration of joint motion should be the primary goal of treatment. Many procedures have been suggested for the treatment of noncontainable hips with LCP disease. If the femoral head and acetabulum become congruent when the joint is adducted but are incongruent in other positions, a valgus femoral osteotomy is the likely preferred option. A valgus femoral osteotomy overcomes the hinging and brings a more congruent surface of the femoral head under the acetabulum102. The advantages of a valgus femoral osteotomy include the correction of abnormal hinge movement by repositioning the hinge segment away from the acetabular margin, correction of the shortening due to fixed adduction, and improvement in the abductor mechanism by increasing the abductor muscle contractile length. Controversy exists as to whether or not an acetabular procedure should be performed to cover the extruded or uncovered femoral head as a combined procedure at the time of a valgus femoral osteotomy. Most authors have suggested that acetabular procedures may not be advisable in younger patients after a valgus osteotomy as lateral acetabular growth can improve once the hinging pressure is relieved. Bankes et al.103 reported favorable remodeling of the femoral head 10 years after a valgus extension osteotomy without a simultaneous acetabular procedure in cases of hinge abduction. A concomitant pelvic procedure may also negate any impingement relief.
Shelf acetabuloplasty augments the anterolateral acetabular edge, thereby increasing the femoral head coverage, and is intended to promote long-term congruency between the uncovered femoral head and the opposing acetabulum104. Some authors have advocated the use of labral support shelf acetabuloplasty for the containment of extruded hips in earlier stages of the disease69,105-108, whereas others have suggested the use of shelf acetabuloplasty as a salvage procedure in cases of late LCP disease109,110. In a recent meta-analysis, Kadhim et al.111 compared the final radiographic outcome (determined with the Stulberg classification system) between patients who were managed with shelf acetabuloplasty for containment in the early stages of LCP disease and those in whom the procedure was performed in later stages as a reconstruction or salvage procedure. The findings of that meta-analysis showed good outcomes for 85% of patients in whom shelf acetabuloplasty was performed in the early stages for containment, compared with 69% of those in whom it was performed in the late stages for reconstruction. Hence, the outcome of shelf acetabuloplasty and the efficacy of treatment were related to the timing of operative intervention. However, another meta-analysis of 13 studies investigating the prevention of secondary degenerative osteoarthritis after shelf acetabuloplasty for the treatment of LCP disease showed uncertainty, with no prospective studies and a low level of evidence112.
Other Operative Procedures
Core decompression is a technique for the treatment of idiopathic juvenile osteonecrosis, which differs from LCP disease in that the patients are older and have less remodeling potential of the femoral head56,113. The objectives of core decompression are to remove necrotic bone, to reduce venous congestion, and to induce revascularization114 with the aim of maintaining or promoting a spherical femoral head. The literature includes a limited number of case series that have investigated the results of core decompression for the treatment of idiopathic juvenile osteonecrosis114,115.
Arthrodiastasis is an operative method that does not change the anatomy of the hip joint but provides unloading of the joint, which negates the effect of the stresses on the articular surfaces and may promote the healing of the areas of necrosis with the induction of neovascularization116. In addition, Salter showed that distraction of a joint could improve healing of articular cartilage in a rabbit model117. Arthrodiastasis has been used in the early stages of LCP disease118 and can be applied as a salvage procedure in patients older than 8 years of age with advanced LCP disease119. The benefits of articulated hip arthrodiastasis include improvement in terms of joint stiffness at the expense of the risk of pin-track infection or failure. These studies investigating arthrodiastasis for the treatment of LCP disease included small numbers of patients with no controls and a short follow-up period.
Operative hip dislocation has been used to address both intra-articular and extra-articular abnormalities around the hip joint in young adults. Operative hip dislocation is capable of addressing residual deformities of the proximal part of the femur in patients with healed LCP disease120,121. Intra-articular abnormalities such as femoroacetabular impingement and coxa magna can be addressed with osteochondroplasty of the head-neck junction and femoral head reduction surgery, respectively121-123. Extra-articular abnormalities such as femoral neck shortening or greater trochanter overgrowth can be approached with relative femoral neck lengthening and greater trochanteric advancement to improve abductor strength and reduce impingement124,125. Both surgeon experience and volume are critical to minimize complications and optimize patient outcomes. Therefore, it remains to be seen how hips with healed LCP disease will perform in the long term following these advanced joint-preserving procedures. Finally, total hip arthroplasty remains a salvage procedure for subsequent secondary degenerative osteoarthritis in patients with healed LCP disease.
The ideal treatment for LCP remains elusive, with the prognosis being determined by the age of the patient at the time of onset, the extent of epiphyseal involvement, and the stage of disease. The best approach is controversial, with surgeons continuing to disagree on how to treat this disease. The current evidence suggests that operative treatment increases the possibility of a spherical femoral head, but the magnitude of this improvement is small and the number needed to treat6,7 remains high because of a modest treatment effect. As such, additional research into epidemiology, pathogenesis, and treatment is required in the search for multimodal treatments that may provide greater improvements in outcomes for patients with LCP disease. In addition, antiresorptive and anabolic agents need further investigation to assess their clinical role and efficacy in the treatment of LCP disease.
Investigation performed at Orthopaedic Research and Biotechnology, Department of Orthopaedic Surgery, Children’s Hospital at Westmead, Sydney, Australia, and Department of Orthopaedic Surgery, Hamad General Hospital, Doha, Qatar
Disclosure: No external funds were received in support of this study. On the Disclosure of Potential Conflicts of Interest forms, which are provided with the online version of the article, one or more of the authors checked “yes” to indicate that the author (or the author’s institution) had a relevant financial relationship in the biomedical arena outside the submitted work and “yes” to indicate that the author had a patent and/or copyright, planned, pending, or issued, broadly relevant to this work.
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