Legg-Calvé-Perthes Disease: Diagnosis, Decision Making, and Outcome.

ABSTRACT: Legg-Calvé-Perthes disease (LCPD), or idiopathic avascular necrosis of the proximal capital femoral epiphysis in children, has a variable presentation and can result in significant femoral head deformity that can lead to long-term functional deficits. Plain radiographic imaging is crucial in diagnosing LCPD and guiding treatment. Although the etiology of LCPD remains unknown, the evolution of the disease has been well characterized to include the phases of ischemia, revascularization, and reossification. The mechanical weakening during these phases of healing place the femoral head at high risk of deformity. Treatment of LCPD, therefore, focuses on minimizing deformity through operative and nonoperative strategies to reduce the risk of premature osteoarthritis. Advanced imaging using perfusion MRI may refine surgical decision making in the future, and biological treatments to improve femoral head healing are on the horizon.

Does Flexion Varus Osteotomy Improve Radiographic Findings Compared With Patients Treated in a Brace for Late-onset Legg-Calvé-Perthes Disease?

BACKGROUND: Legg-Calvé-Perthes disease (LCPD) is a childhood hip disease characterized by osteonecrosis of the femoral head. Because severe deformity of the femoral head can cause secondary osteoarthritis in adulthood, progressive collapse should be prevented in children with a necrotic epiphysis. The prognosis of patients with LCPD generally worsens as the age at disease onset increases, and the appropriate treatment for late-onset LCPD remains unclear. Based on the limited effect of nonoperative treatment using a nonweightbearing brace, flexion varus osteotomy (FVO) was introduced in 2010 as an initial treatment for late-onset LCPD in place of brace treatment, which we used in our institution before that time. QUESTIONS/PURPOSES: We asked, (1) Which treatment, FVO or a nonweightbearing brace, is associated with a lower likelihood of progressive femoral head collapse in children whose diagnosis of LCPD was made at the age of ≥ 8 years and who were followed for a minimum of 3 years after their intervention? (2) What proportion of patients in the brace group had surgery despite the treatment, and what percentage of children in the FVO group had a second operation to remove hardware and/or additional operations? METHODS: The initial treatment was applied in 181 patients with LCPD between 1995 and 2018 in our institution. Patients whose disease onset was at ≥ 8 years old (late-onset LCPD) with complete clinical and radiologic data were considered potentially eligible. In 2010, treatment for these patients changed from brace treatment to FVO for all patients. A total of 35% (42 of 121) of patients who were treated with a nonweightbearing brace between 1995 and 2009 and 40% (24 of 60) of patients who were treated with FVO between 2010 and 2018 were eligible. Among patients treated with a brace, 21% (nine of 42 patients) were excluded because of hospital transfer (three patients), short-term follow-up (three), the period from onset to the first visit was ≥ 7 months (two), and inability to use the brace because of mental incapacity (one patient). In patients treated with FVO, 12% (three of 24 patients) were excluded (two patients with a period from onset to the first visit ≥ 7 months and one with a comorbidity and multiple-epiphyseal dysplasia). Among the remaining patients, 79% (33 of 42 patients) were classified into the brace group and 88% (21 of 24 patients) were classified into the FVO group for analyses. There were no overlapping patients at the timepoint when the treatment strategy for late-onset LCPD changed. In the FVO group, subtrochanteric osteotomy with 35° to 40° of flexion and 15° to 20° of varus was performed using a locking compression plate for pediatric use. Patient demographics, radiographic parameters, and the assessment of femoral head deformity using the Stulberg classification were compared between the two groups. There was a greater proportion of boys than girls in both groups (brace: 88% and FVO: 86%), and there were no differences in the distribution of genders between the groups (p = 0.82). The right side was more frequently treated in the brace group, but there was no difference in laterality between the groups (brace: 58% right and FVO: 62% left; p = 0.16). There was no difference between groups in the median age at disease onset (9.0 years [range 8.0 to 12.5 years] in the brace group and 9.6 years [range 8.0 to 12.4 years] in the FVO group; p = 0.26). There was no difference between the groups in the period of treatment from onset (1.7 ± 1.9 months in the brace group and 1.5 ± 1.5 months in the FVO group; p = 0.73) or the follow-up period (6.7 ± 2.1 years in the brace group and 6.2 ± 2.1 years in the FVO group; p = 0.41). The LCPD stage at the first visit was assessed using the modified Waldenström classification. The intraobserver and interobserver values of the modified Waldenström classification, evaluated using kappa statistics, were excellent (kappa value 0.89 [95% CI 0.75 to 0.97]; p < 0.01) and good (kappa value 0.65 [95% CI 0.43 to 0.87]; p < 0.01). The radiographic degree of collapse at the maximum fragmentation stage was assessed using the lateral pillar classification. The intraobserver and interobserver reliabilities of the lateral pillar classification were excellent (kappa value 0.84 [95% CI 0.73 to 0.94]; p < 0.01) and excellent (kappa value 0.83 [95% CI 0.71 to 0.94]; p < 0.01). The degree of femoral head deformity at the most recent follow-up examination was compared between the groups in terms of the Stulberg classification, in which Classes I and II were classified as good and Classes III through V were classified as poor. The intraobserver and interobserver reliabilities of the Stulberg classification were good (kappa value 0.74 [95% CI 0.55 to 0.92]; p < 0.01) and good (kappa value 0.69 [95% CI 0.50 to 0.89]; p < 0.01). The evaluators were involved in the patients' clinical care as part of the treating team. RESULTS: Good radiographic results (Stulberg Class I or II) were obtained more frequently in the FVO group (76% [16 of 21 patients]) than in the brace group (36% [12 of 33 patients]), with an odds ratio of 5.6 (95% CI 1.7 to 18.5; p < 0.01). In the brace group, a subsequent femoral varus osteotomy was performed in 18% (six of 33) of patients with progressive collapse and hinge abduction, and implant removal surgery was performed approximately 1 year after the first procedure. This traditional varus osteotomy was occasionally performed in patients who were considered for conversion from nonoperative treatment before 2009 because FVO had not yet been introduced. In the FVO group, all patients (n = 21) had a second procedure to remove the implant at a mean of 10.5 ± 1.2 months postoperatively. Additional procedures were performed in 24% (five of 21) of patients, including a second FVO for progressive collapse (one patient), guided growth for a limb length discrepancy (one patient), and flexion valgus osteotomy for coxa vara in patients with a limb length discrepancy (three patients). CONCLUSION: Our historical control study found that FVO may increase the possibility of obtaining good radiographic results (Stulberg Class I or II) compared with brace treatment for patients with late-onset LCPD, although surgical interventions after the first and second implant removal procedures may be indicated. Surgeons can consider FVO if they encounter patients with late-onset LCPD, which is a challenging condition. A larger study with long-term follow-up is needed to confirm the efficacy of FVO. LEVEL OF EVIDENCE: Level III, therapeutic study.

Skeletal Maturity in Legg-Calve-Perthes Disease: Significant Discrepancy Present Between the Hand and the Hip.

BACKGROUND: The concept of delayed skeletal maturity in Legg-Calve-Perthes Disease (LCPD) has been well identified with the Greulich and Pyle (GP) atlas showing 1 to 2 years delay. Recently the optimized Oxford hip skeletal age (Optimized Oxford) system has been developed and shown to have similar accuracy as the GP atlas for assessing skeletal maturity. However, this system has not been used to assess skeletal maturity in LCPD. METHODS: A retrospective review of a prospective, multicenter study of patients with LCPD treated from 1984 to 1991 and followed to skeletal maturity was performed. We identified all patients who had a left-hand radiograph at the time of presentation with an accompanying anteroposterior pelvis radiograph including the contralateral hip. Patients were excluded if their age at presentation fell outside the validated range for the Optimized Oxford system. GP atlas was used to determine bone age using left-hand radiographs and the nonaffected hip radiographs were used to calculate the Optimized Oxford bone age. Skeletal maturity indices were compared with chronological age (CA) to determine the discrepancy between methodologies. RESULTS: A total of 71 patients met inclusion criteria (mean 9.5 ± 1.2 y at presentation, 42.2% females). The mean GP bone age was 1.4 years younger than CA (95% CI: 1.01-1.76 y), with the discrepancy being greater for boys than girls (1.8 vs 0.86 y, P = 0.02). The mean Optimized Oxford bone age was 0.31 years older than CA (95% CI: 0.24-0.38 y) and correlated significantly with CA ( R = 0.97, P < 0.001). There were no sex differences in the Optimized Oxford bone age relative to CA ( P = 0.32). The GP bone age was a mean of 1.7 years younger than the Optimized Oxford bone age (95% CI: 1.35-2.05 y). CONCLUSION: Skeletal maturity assessment in children with LCPD varies according to the utilized maturity system. The Optimized Oxford bone age more closely mirrors the patient's CA and does not correlate with the GP bone age, which reveals a delayed maturation.

A Comparison Between 3 Functional Hip Scores for Evaluation of the Pediatric Hip.

BACKGROUND: This investigation aimed to determine the degree of correlation among 3 functional scales for evaluating the hip in pediatric patients and determine the correlation between measures of global function and outcome. METHODS: We performed a prospective study of 173 consecutive patients (M age = 13 ± 3 y) being followed for developmental dysplasia of the hip (n = 122, 71%), slipped capital femoral epiphysis (n = 31, 18%), or Legg-Calve-Perthes disease (n = 20, 12%). We evaluated patients clinically, and we compiled scores for the Iowa Hip Score (IHS), Harris Hip Score (HHS), and Children's Hospital Oakland Hip Evaluation Scale (CHOHES). Patients concomitantly completed the Pediatric Outcomes Data Collection Instrument (PODCI) at the same clinic visit. We assessed Global Functioning Scale the and the Sports and Physical Functioning Core Scale of the PODCI. We determined the degree of correlation between the functional hip scales and between each scale and the PODCI scales using Spearman rank correlation coefficients. RESULTS: The correlations between the IHS, HHS, and CHOHES scores were robust (IHS and HHS ρ = 0.991; IHS and CHOHES ρ = 0.933; HHS and CHOHES ρ = 0.938; all P < 0.001). The correlation between the Global Functioning Scale of the PODCI and the 3 hip scores was ρ = 0.343 for the IHS, ρ = 0.341 for the HHS, and ρ = 0.352 for the CHOHES (all P < 0.001). The correlation between the sports and physical functioning core scale of the PODCI and the 3 hip scores was ρ = 0.324 for the IHS, ρ = 0.329 for the HHS, and ρ = 0.346 for the CHOHES (all P < 0.001). CONCLUSIONS: In a pediatric population with diverse hip pathology, there was a very strong correlation between scores on the IHS, HHS, and CHOHES. However, none of these 3 most commonly used hip scores correlated strongly with the global functioning scale or sports and physical functioning core scale of the PODCI. The most frequently used scores to determine the outcome of pediatric patients with hip pathology correlate strongly with each other but do not necessarily relate to global functional results. LEVEL OF EVIDENCE: Level IV.

Does Prolonged Weight Relief Increase the Chances of a Favourable Outcome After Containment for Perthes Disease?

We have been treating children with Legg-Calvé-Perthes disease (LCPD) with a femoral varus osteotomy (PFVO) and weight relief till the disease evolves to the latter part of the stage of reconstitution (Stage IIIb). This entails weight relief for 18 to 24 months. We undertook this case-control study to test if a shorter period of weight relief would compromise the chance of retaining the spherical shape of the femoral head when the disease healed. Forty-one children diagnosed in the early stages of LCPD (Stages Ia, Ib, and IIa), were treated by PFVO and non-weight-bearing for a period of 6 months following surgery (6m group). Eighty-two children with LCPD matched for age, sex, and stage at surgery, who resumed weight-bearing only once they reached Stage IIIb, served as the control group (3b group). Both groups were followed up till the disease healed. The sphericity deviation score was calculated, and the height and width of the epiphysis were measured on the first radiograph designated as Stage IV. The median sphericity deviation score value at healing was 3 in the 3b group and 11 in the 6m group (P<0.001). The frequency of spherical heads was 76% in the 3b group and 49% in the 6m group (P<0.003). The Odds Ratio of the disease healing with an aspherical head in 6-month group was 3.05 (CI: 1.28 to 7.22) compared with the 3b group. The percentage increase in width of the femoral epiphysis at healing was greater in the 6 group (111.5±8.5% vs. 106.5±7.2%; P<0.001). The study confirms that containment by PFVO performed early in the course of LCPD combined with weight relief till the disease has evolved to Stage IIIb is likely to result in spherical hips in 75% of children. Reducing the period of weight relief to 6 months may yield significantly poorer results with only 49% spherical femoral heads.

Reliability of the Modified Method for Sphericity Deviation Score Using Only the Involved Hip Radiographs in the Patients With Legg-Calve-Perthes Disease.

BACKGROUND: The sphericity deviation score (SDS) is a validated radiographic outcome measure that quantifies the severity of the femoral head deformity in the healed stage of Legg-Calve-Perthes disease (LCPD). The current method requires radiographs of both hips regardless of unilateral involvement to standardize radiographic magnification. As LCPD affects the unilateral hip in 85% to 90% of cases, the current method imposes unnecessary radiation exposure to most of the patients and having to exclude patients from research studies who only had unilateral hip radiographs. We thus modified the SDS method to use unilateral hip radiographs. The purpose of this study was to investigate the reliability of the modified SDS method using the radiographs containing only one hip. METHODS: This retrospective study involved 40 patients with LCPD with unilateral involvement in the healed stage of LCPD. We modified the SDS measurement method by using the distance between the teardrop and the lateral acetabulum for magnification correction and providing a clear anatomic description of reference points on the femoral head. Three independent observers performed measurements using radiographs containing the affected hip only (modified method) and both hips (conventional method). The intraclass correlation (ICC) estimates were calculated. To verify clinical relevance, the correlation of the SDS with the Stulberg classification and hip range of motion (ROM) were also investigated. RESULTS: Measurements using the modified SDS showed excellent inter-/intra-observer ICCs (0.903 to 0.978). The ICCs between the modified and conventional methods were also excellent: 0.940 to 0.966 within the same observer and 0.897 to 0.919 between different observers. The modified SDS showed moderate-to-strong correlations with the Stulberg classification (Spearman ρ=0.650) and hip ROM (Pearson r =-0.661). CONCLUSION: The modified SDS measurement method showed excellent inter-/intra-observer reliability and moderate-to-strong correlations with the Stulberg classification and hip ROM. This method will help reduce unnecessary radiation exposure in patients with unilateral LCPD and prevent the exclusion of patients with unilateral radiographs from future research studies. LEVEL OF EVIDENCE: Level III-diagnostic study.

Development of acetabular retroversion in LCPD hips-an observational radiographic study from early stage to healing.

BACKGROUND: Acetabular retroversion is observed frequently in healed Legg-Calvé-Perthes disease (LCPD). Currently, it is unknown at which stage and with what prevalence retroversion occurs because in non-ossified hips, retroversion cannot be measured with standard radiographic parameters. METHODS: In a retrospective, observational study; we examined pelvic radiographs in children with LCPD the time point of occurrence of acetabular retroversion and calculated predictive factors for retroversion. Between 2004 and 2017, we included 55 children with a mean age of 5.7 ± 2.4 years at diagnosis. The mean radiographic follow-up was 7.0 ± 4.4 years. We used two new radiographic parameters which allow assessment of acetabular version in non-ossified hips: the pelvic width index and the ilioischial angle. They are based on the fact that the pelvic morphology differs depending on the acetabular version. These parameters were compared among the four Waldenström stages and to the contralateral side. Logistic regression analysis was performed to determine predictive factors for acetabular retroversion. RESULTS: Both parameters differed significantly among the stages of Waldenström (p < 0.003 und 0.038, respectively). A more retroverted acetabulum was found in stage II and III (prevalence ranging from 54 to 56%) compared to stage I and IV (prevalence ranging from 23 to 39%). In hips of the contralateral side without LCPD, the prevalence of acetabular retroversion was 0% in all stages for both parameters. Predictive factors for retroversion were younger age at stage II and IV, collapse of the lateral pillar in stage II or a non-dysplastic hip. CONCLUSIONS: This is the first study evaluating acetabular version in children with LCPD from early stage to healing. In the developing hip, LCPD may result in acetabular retroversion and is most prevalent in the fragmentation (stage II) and early healing stage (stage III). Partial correction of acetabular retroversion can occur after healing. This has a potential clinical impact on the timing and type of surgical correction, especially in pelvic osteotomies for correction of acetabular version. LEVEL OF EVIDENCE: Level III, retrospective observational study.

Quantitative T2 and T1ρ mapping are sensitive to ischemic injury to the epiphyseal cartilage in an in vivo piglet model of Legg-Calvé-Perthes disease.

OBJECTIVE: To determine if the quantitative MRI techniques T2 and T1ρ mapping are sensitive to ischemic injury to epiphyseal cartilage in vivo in a piglet model of Legg-Calvé-Perthes disease using a clinical 3T MRI scanner. We hypothesized that T2 and T1ρ relaxation times would be increased in the epiphyseal cartilage of operated vs contralateral-control femoral heads 1 week following onset of ischemia. DESIGN: Unilateral femoral head ischemia was surgically induced in eight piglets. Piglets were imaged 1 week post-operatively in vivo at 3T MRI using a magnetization-prepared 3D fast spin echo sequence for T2 and T1ρ mapping and a 3D gradient echo sequence for cartilage segmentation. Ischemia was confirmed in all piglets using gadolinium contrast-enhanced MRI. Median T2 and T1ρ relaxation times were measured in the epiphyseal cartilage of the ischemic and control femoral heads and compared using paired t-tests. Histological assessment was performed on a subset of five piglets. RESULTS: T2 and T1ρ relaxation times were significantly increased in the epiphyseal cartilage of the operated vs control femoral heads (ΔT2 = 11.9 ± 3.7 ms, 95% CI = [8.8, 15.0] ms, P < 0.0001; ΔT1ρ = 12.8 ± 4.1 ms, 95% CI = [9.4, 16.2] ms, P < 0.0001). Histological assessment identified chondronecrosis in the hypertrophic and deep proliferative zones within ischemic epiphyseal cartilage. CONCLUSIONS: T2 and T1ρ mapping are sensitive to ischemic injury to the epiphyseal cartilage in vivo at clinical 3T MRI. These techniques may be clinically useful to assess injury and repair to the epiphyseal cartilage to better stage the extent of ischemic damage in Legg-Calvé-Perthes disease.

Jacques Calvé, 1875-1954.

This history page in the series "Leaders in MSK Radiology" is dedicated to the memory and achievements of the French physician Jacques Calvé, whose name is partially associated with the medical eponym Legg-Calvé-Perthes disease.

Does the Deformity Index Reliably Predict the Shape of the Femoral Head at Healing of Legg-Calvé-Perthes Disease?

BACKGROUND: Treatment of Legg-Calvé-Perthes disease (LCPD) aims to preserve the spherical shape of the femoral head. The deformity index (DI) <0.3, measured 2 years from disease onset, is a surrogate measure that predicts that the femoral head will be Stulberg class I or II at skeletal maturity. There is no study that compares the predictive value of DI against a quantitative measure of the shape of the femoral head when the disease heals. We undertook this study to assess the reproducibility of a new method of measurement of DI and see if DI could predict the shape of the femoral head when the disease healed. METHODS: DI was measured 2 years after disease onset and the Sphericity Deviation Score (SDS) was measured at healing of LCPD on radiographs of 43 children. Reproducibility of measurement was tested. Each healed femoral head was classified as spherical or aspherical based on subjective visual assessment. The DI values were compared with SDS values. RESULTS: The reproducibility of measurement of SDS was excellent and superior to that of DI. The mean duration of disease was 3.97±0.96 years. Only 17 of 32 hips with DI values <0.3 at 2 years had spherical femoral heads at healing (SDS <10). Three hips with SDS values <10 had DI values >0.3. The positive and negative predictive values of a DI <0.3 in predicting if the femoral head will be spherical (SDS <10) when the disease healed were 53% and 73%, respectively. CONCLUSION: Though DI can be reproducibly measured the predictive value of a DI <0.3, to accurately identify hips that are likely to heal with spherical femoral heads, is not sufficiently high to justify its use as an outcome measure.

Radiologic Outcomes of Bilateral and Unilateral Perthes Disease: A Comparative Cohort Study.

INTRODUCTION: This study was undertaken to compare the radiologic outcomes of bilateral and unilateral Perthes disease and also to evaluate the outcome of synchronous and metachronous bilateral Perthes disease. METHODS: Of 353 children with Perthes disease followed up from presentation to healing during the last 10 years, 37 had bilateral involvement (11 synchronous and 26 metachronous onset). The radiologic outcomes of each hip of children with bilateral disease were compared with outcomes of 148 children with unilateral disease who were matched for age, sex, and treatment. Children with unilateral or bilateral diseases were treated with a proximal femoral varus derotation osteotomy if they fulfilled the criteria for surgery. The primary outcome measure was the shape of the femoral head at healing assessed by the Sphericity Deviation Score (SDS). RESULTS: The children with bilateral disease were younger than those with unilateral disease (6.2 vs. 7.03 y; P<0.001), and they had a longer duration of the disease. All other characteristics of bilateral and unilateral cases were similar. The SDS values of unilateral and bilateral disease were comparable, as were the SDS of synchronous and metachronous bilateral disease. The effect of early surgery on the evolution of the disease in bilateral cases was similar to that reported in unilateral disease. The age of onset of the disease alone influenced the SDS in bilateral cases. CONCLUSION: The age at onset of the bilateral disease is lower, the duration of the disease longer than that of unilateral disease, but the disease outcome is similar.

Novel Minimally-Invasive Triple Pelvic Osteotomy: JiShuiTan Minimally-Invasive Approach.

PURPOSE: Triple pelvic osteotomy (TPO) is often performed to improve femoral head coverage, correct deformity, and stabilize the hip joint in a variety of pediatric orthopaedic conditions. After the TPO was first reported, many modifications were developed to simplify or improve the procedure, however, because of the specific anatomy with several critical nerves and vessels passing through the approaches, extensive exposure and prolonged intraoperative fluoroscopy are often required for TPO. This report introduces a novel, minimally-invasive surgical approach that minimizes the time of intraoperative fluoroscopy and size of the surgical incision, and reviews our experience. METHODS: A total of 48 hips in 43 patients with a mean age of 8.3±1.7 years (range: 6.0 to 12.2 y) were included in this study. Of these, 21 patients (22 hips) had Legg-Calvé-Perthes disease (LCPD) and 22 patients (26 hips) had developmental dysplasia of the hip (DDH). The TPOs were performed using the novel, minimally-invasive TPO approach, with a mean postoperative follow-up of 38 months (range: 24 to 54 mo) in the DDH group and 44 months (range: 23 to 58 mo) in the LCPD group. The acetabular index (AI), femoral head migration rate (MP), center edge angle (CEA) and the Severin and Stulberg classification systems were used to evaluate the preoperative and postoperative results. SPSS software was used to analyze the data. RESULTS: The AI decreased from 33.8 degrees±9.2 to 2.9 degrees±10.1, the lateral CEA increased from -10.8 degrees±23.8 to 34.1 degrees±9.9, and the femoral head MP decreased from 64.0%±19.8% to 1.1%±2.6% in the DDH group at last follow-up, indicating significant improvement. The AI decreased from 20.8 degrees±4.7 to -1.3 degrees±7.3, the lateral CEA increased from 6.8 degrees±11.5 to 42.3 degrees±6.4, and the femoral head MP decreased from 42.2%±13.0% to 1.3%±3.3% in the LCPD group at last follow-up, also indicating significant improvement. CONCLUSION: This approach can simplify the TPO, making the complex operation safer, more effective, and capable of achieving satisfactory correction.

Bypass of Epiphyseal Fragmentation Following Early Salter Innominate Osteotomy and Its Clinical Relevance in Legg-Calvé-Perthes Disease.

BACKGROUND: It has been demonstrated that early femoral varus osteotomy (FVO) produces a greater probability of skipping or interruption of epiphyseal fragmentation, thereby shortening the length of fragmentation stage for hips in the active stage of Legg-Calvé-Perthes disease. This "bypassing phenomenon" is thought to effect less disease severity or outcome, whereas it remains to be elucidated whether this phenomenon is specific to early FVO. We sought to investigate the presence and characteristics of the "bypassing phenomenon" following pelvic osteotomy performed in the avascular necrosis or early fragmentation stage as well as its correlation with disease severity and radiographic outcomes. METHODS: A retrospective review of data was conducted for 79 patients with unilateral Legg-Calvé-Perthes disease who had been diagnosed from 1987 to 2015, undergone the Salter innominate osteotomy (SIO) during the stage of avascular necrosis or in the early part of the fragmentation stage between 6.0 and 12.0 years of age, and followed up until skeletal maturity. Epiphyseal fragmentation was classified into 4 patterns according to a previous study. We compared lateral pillar groups and Stulberg grades between patients with and without bypass of the fragmentation stage. RESULTS: The mean age at surgery and follow-up period was 8.1 and 7.9 years, respectively. Sixty hips were in the Waldenström stage I and 19 hips in stage IIa at the surgery. In hips receiving SIO during stage I, the mean duration of the fragmentation stage was 276 days. The fragmentation pattern was typical for 40 hips, abortive for 17 hips, and atypical with horizontal fissure for 3 hips. Patients whose fragmentation was aborted experienced significantly less severe lateral pillar involvement and more favorable Stulberg outcomes at skeletal maturity. CONCLUSIONS: Incomplete bypass of epiphyseal fragmentation was observed in 28% of patients following early SIO performed in the avascular necrosis stage. In contrast to FVO, no patient bypassed fragmentation completely. Patients with incomplete bypass had a significantly higher proportion of less severe hips and a significantly greater probability of being associated with favorable radiographic outcomes compared with those without bypass. LEVEL OF EVIDENCE: Level IV-therapeutic study.

The Role of the Artery of Ligamentum Teres in Revascularization in Legg-Calve-Perthes Disease.

INTRODUCTION: A recent cadaveric study supported that most immature hips are supplied by the artery of ligamentum teres and suggested this medial vascular source may influence the pattern of revascularization in Legg-Calve-Perthes disease (LCPD). The purposes of this study were to characterize the perfusion pattern of the capital femoral epiphysis and determine the role of the artery of ligamentum teres in early revascularization of LCPD. METHODS: Retrospective review of perfusion magnetic resonance imaging (pMRI) from 64 hips in early stage LCPD (Waldenström stage I to IIa) was performed. Two independent graders categorized perfusion pattern based on the presence of perfusion medially (from artery of ligamentum teres) and/or laterally (from the medial femoral circumflex artery) on coronal and sagittal MRI series: type 1-lateral perfusion only, type 2-separate medial and lateral perfusion, or type 3-coalescent medial and lateral perfusion. Lateral pillar classification was obtained for hips that reached mid-fragmentation. RESULTS: We identified 64 patients (75% male) with mean age at diagnosis of 8.5±2.1 years. 36% (23/64) hips underwent pMRI during stage I and 64% (41/64) during stage IIa. pMRI revealed separate and distinct medial and lateral sources of perfusion (type 2) in 50% (32/64) hips. In stage I, the distribution of type 1/2/3 hips was found to be 26%/52%/22%. However, in stage IIa there was a nonsignificant trend toward greater coalescence of the medial and lateral perfusion with a distribution of type 1/2/3 of 7%/49%/44% (P=0.07). There was a nonsignificant trend toward weak negative linear correlation between lower initial perfusion grade and worsened lateral pillar classification at mid-fragmentation (r=-0.25, P=0.05). CONCLUSION: The presence of separate and distinct areas of perfusion of medial and lateral capital femoral epiphysis provides further evidence of the role of the ligamentum teres vessels in revascularization during the early stages of LCPD. The changes in perfusion pattern with disease progression likely reflect that medial femoral circumflex artery and ligamentum teres vessel revascularization occur separately, but ultimately coalesce posteriorly over time. LEVEL OF EVIDENCE: Level II-prognostic study.

The "Discoid Epiphysis"-An Uncommon Presentation of Legg-Calvé-Perthes Disease.

BACKGROUND: Among a cohort of 402 children with Legg-Calvé-Perthes disease (LCPD), 32 children presented with sclerosis and severe collapse of the entire femoral epiphysis that closely resembled a discus.This study was undertaken to identify the characteristics of children with this form of a "discoid epiphysis," compare them with typical LCPD and ascertain the radiologic outcome of their hips when the disease healed. METHODS: Sequential radiographs of the children were studied to monitor disease evolution. Femoral epiphyseal extrusion was measured on the initial anteroposterior radiograph. Thirty-one of the 32 children were treated with a proximal femoral varus osteotomy and weight-bearing was deferred till the disease reached stage IIIb. The pattern of fragmentation of the epiphysis was noted and the Sphericity Deviation Score (SDS) was computed once the disease healed. RESULTS: The mean age of children with a discoid epiphysis was 6.81±1.57 years at onset of symptoms while that of children with the typical presentation was 7.54±1.64 years (P<0.017). Perfusion magnetic resonance imaging scans of three children with a discoid epiphysis done in stage Ib of the disease showed that over 95% of the epiphysis was avascular. Femoral head extrusion was frequently present on the initial radiographs (mean Reimer's migration index 27.08±8.7; range: 6.4 to 42.55).In operated children with a discoid epiphysis, the disease evolved typically with fragmentation of the epiphysis followed by reconstitution. The height of the epiphysis was never restored; when the disease healed the mean epiphyseal height was 51.31±10.44% of the normal contralateral epiphysis as compared with 82.46±11.24% in children with typical LCPD (P<0.001).The SDS at healing of operated children with a discoid epiphysis was 14.95±10.86 while the SDS for operated children without a discoid epiphysis was 9.77±11.7 (P<0.019). However, the SDS of children with typical onset LCPD who had Catterall IV involvement and Herring C collapse was 15.25±15.19 (P=0.49 NS). CONCLUSION: The outcome of treatment of children with a discoid epiphysis is comparable to that of children with typical onset LCPD with Catterall IV (whole-head involvement) and Herring C collapse of the lateral pillar. About a third of these children who undergo early surgical containment may have spherical heads when the disease heals.

Effect of Postoperative Femoral Neck Shaft Angle on Femoral Head Sphericity Following Proximal Femoral Osteotomy in Legg-Calve-Perthes Disease.

BACKGROUND: Herein, we aimed to examine the relationship between the postoperative neck shaft angle (NSA) and the Stulberg outcome at skeletal maturity in patients with Legg-Calvé-Perthes disease (LCPD) who underwent proximal femoral varus osteotomy (PFVO) and to determine the optimal angle of varization. METHODS: In this retrospective study, we analyzed the data of 90 patients aged older than 6 years at the time of diagnosis with LCPD who underwent PFVO at our institution between 1979 and 2014. Univariate and multivariate logistic regression analyses were used to examine the effects of variables on the sphericity of the femoral head at skeletal maturity, including the age at onset, sex, stage at operation, extent of epiphyseal involvement and epiphyseal collapse, presence of specific epiphyseal, metaphyseal, and acetabular changes, and postoperative NSA. The sphericity of the femoral head on the final plain follow-up radiographs of the hip joint at skeletal maturity was assessed using the Stulberg classification. Cases of spherical femoral head (Stulberg I or II) were rated as good, whereas those of ovoid or flat femoral head (Stulberg III, IV, or V) were rated as bad. RESULTS: The mean age at diagnosis was 7.93 (range, 6.0-12.33) years. The average follow-up period was 10.11 (range, 5.25-22.92) years. The pre and postoperative mean NSAs were 137.31±6.86 degrees (range, 115.7-158 degrees) and 115.7±9.83 degrees (range, 88.6-137.6 degrees), respectively. The age at diagnosis, lateral pillar classification, and postoperative NSA were found to be closely related to the sphericity of the femoral head at skeletal maturity. Patients with a postoperative NSA of <105 degree or more than 125 degree were less likely to have a spherical femoral head. CONCLUSIONS: Our study showed that patients with a postoperative NSA between 105 and 125 degrees were more likely to have a spherical femoral head. When performing PFVO in patients with LCPD, reasonable varus angulation of PFVO should be taken into consideration for the success of the operation. LEVEL OF EVIDENCE: Level III retrospective cohort study.

Predictors of radiographic outcomes of conservative and surgical treatment of Legg-Calvé-Perthes disease.

PURPOSE: Treatment outcomes of conservative and surgical treatment of Legg-Calvé-Perthes disease (LCPD) have been shown to be conditioned by a number of factors that may vary across different populations. This retrospective study aimed to evaluate factors affecting radiographically assessed treatment outcomes in patients treated surgically or conservatively for LCPD at Faculty Hospital Motol, Prague, Czech Republic, between the years 2006 and 2019. METHODS: Data of forty-seven children comprising 52 hips were analysed. Treatment outcomes were evaluated according to Stulberg classification. Predictors included the initial stage of fragmentation of the hip joint according to Herring classification, type of treatment (conservative or surgical), age at the time of diagnosis and sex. RESULTS: Older age and severity of LCPD according to Herring classification but not the type of treatment were the strongest factors determining treatment outcomes. Treatment outcomes were comparable in patients treated conservatively or surgically both across the whole cohort of patients and a group of young children < six years of age. CONCLUSIONS: Results strengthen the roles of severity of the LCPD at onset of treatment and age of the patient in predicting treatment outcomes in patients with LCPD. Conservative and surgical treatments appear to yield similar treatment outcomes irrespective of age of patients.

Comparative effectiveness of treatment modalities in severe Legg­Calvé­Perthes disease: Systematic review and network meta­analysis of observational studies.

PURPOSE: There are several treatment modalities for Legg-Calvé-Perthes disease (LCPD), self-limiting, avascular osteonecrosis of the femoral head in children. Most treatments focus on containment of the weakened femoral head, but there is no consensus on the best modality for severe LCPD. Therefore, we compared the effectiveness of all treatment modalities for severe LCPD. MATERIALS AND METHODS: We searched the PubMed, Embase, and Scopus up until July 2021 for studies that investigated LCPD treatment effectiveness. A network meta-analysis was performed to examine the comparative effectiveness in terms of the ability to achieve radiographic spherical congruity of the hip joint after skeletal maturity. The risk ratio (RR) and 95% confidence interval (CI) of each treatment modality were estimated from both direct and indirect evidence. Treatment ranking was based on Surface Under the Cumulative Ranking curve (SUCRA). RESULTS: A total of 857 studies were identified and 34 comparative studies with 3718 affected hips comparing seven different LCPD treatment modalities were included. Compared with symptomatic treatment, combined osteotomy was the most effective modality (RR = 1.47, 95% CI 0.90 to 2.42, SUCRA = 0.8), followed by femoral varus osteotomy (RR = 1.31, 95% CI 1.06 to 1.60, SUCRA = 0.7), and Salter innominate osteotomy (RR = 1.25, 95% CI 0.95 to 1.65, SUCRA = 0.6). CONCLUSIONS: Combined osteotomy is the most effective procedure in terms of improving the spherical congruity of the hip joint in severe LCPD patients. However, the superiority of operative treatments seems to be limited to patients older than eight years old.

The MRI Effect in Clinical Decision Process in Perthes' Disease: "More Complex Imaging, More Complicated Surgeries".

PURPOSE OF THE STUDY Radiographs are preferred for understanding the deformity and containment in Legg-Calvé-Perthes disease (LCPD), as well as for treatment planning, but plain radiographs provide only static information and are inadequate for dynamic assessment of the joint. Magnetic resonance imaging (MRI) has been shown to be superior to other diagnostic modalities. The aim of this study was to determine the importance of hip MRI in LCPD treatment decision-making processes between pediatric orthopedic surgeons and orthopedic surgery residents. MATERIAL AND METHODS Eight orthopedic surgery residents and eight pediatric orthopedic surgeons were invited to retrospectively evaluate hip radiography images and MRI sections of 34 patients with LCPD. The treatment choices were divided into two groups as conservative and surgical. Gwet's AC1 analysis was used to establish the relative level of intra-observer agreements. The correlation between the professional experience and the agreement parameters was also evaluated using the Pearson correlation coefficient. ANOVA was used to compare multiple groups. p ≤ 0.05 was statistically significant. RESULTS For both groups most preferred treatment method was conservative approaches based on plain radiography and MRI. The resident group showed a significant shift from conservative treatment to surgical treatment choices after MRI evaluation. The difference between the frequencies of each treatment choice for pediatric orthopedic surgeons was not statistically significant among different imaging modalities, but a comparison of the changes in surgical treatment revealed a significant difference between the imaging modalities, with a trend towards more complicated treatment choices. DISCUSSION Conservative methods were the most preferred treatment choice in the study, as it is common. It was observed that treatment choices changed when patients were evaluated together with MRI. Compared to plain radiographs, MRI provides sufficient and particular information for evaluating the structures of the hip joint components. CONCLUSIONS We found that consideration of MRI data in LCPD patients changed treatment recommendations substantially towards more complicated surgical procedures. We consider this to be an 'MRI effect' where using a more complex imaging modality leads surgeons to more complicated treatment modalities in LCPD. Key words: imagnetic resonance imaging, reliability, MRI effect, Perthes disease, children.

Can large doses of glucocorticoids lead to Perthes? a case report and review of the literature.

BACKGROUND: Perthes disease (Legg-Calvé-Perthes, LCP) is a self-limited and non-systemic disease occurring in the femoral heads of children, which is mainly manifested as an ischemic necrosis of the femoral head epiphysis, leading to subchondral ossification injury of the femoral head. CASE PRESENTATION: Here we report a case of 11-year-old child with long-term use of high-dose glucocorticoids. With MRI examination finding the epiphyseal necrosis of right humeral head, femur and tibia, and X-ray examination finding bilateral femoral head necrosis, the child was diagnosed as Perthes disease based on his clinical and imaging data. CONCLUSIONS: Long-term and high-dose glucocorticoids may be one of the causes of Perthes disease.