Legg-Calvé-Perthes Disease

[Pediatric Hip Disorders]

Developmental dysplasia of the hip is a condition characterized by hip joint instability due to acetabular dysplasia in infancy, necessitating precise ultrasound examination. Legg-Calvé-Perthes disease is caused by a temporary disruption in blood flow to the femoral head during childhood, progressing through avascular, fragmentation, re-ossification, and residual stages. Slipped capital femoral epiphysis is a condition where the femoral head shifts medially along the epiphyseal line during adolescence due to stress, such as weight-bearing. Differentiating between transient hip synovitis and septic arthritis may require joint fluid aspiration. Osteomyelitis can be associated with soft tissue edema and osteolysis. When multiple lesions are present, it is essential to distinguish between Langerhans cell histiocytosis and metastatic neuroblastoma. This review will introduce imaging techniques and typical findings for these conditions.

Global trends in the research on Legg-Calve-Perthes disease in Web of Science

Background

Legg-Calve-Perthes disease (LCPD) is a form of idiopathic femoral head necrosis that can lead to permanent femoral head deformities and premature osteoarthritis in children under the age of 15. Its pathogenesis is utterly and remains to be clarified. Although many research publications on LCPD have emerged during the last few decades, few systematic bibliometric analyses of these articles have been reported.

Methods

A bibliometric analysis was performed to investigate the development processes and hotspots, as well as the collaboration and influence among countries, institutions, authors, journals, and keywords of papers relevant to LCPD from the Web of Science Core Collection (WoSCC) during the period from 1 January 2000 to 30 June 2023.

Results

A total of 2,205 researchers from 916 institutions across 53 countries/regions have contributed to 673 papers published in 199 academic journals. The research on LCPD has shown significant fluctuations but a gradual increase in the number of articles published over the last two decades. The United States leads in the number of publications of LCPD, with the Texas Scottish Rite Hospital for Children being the most productive institution. English, as the most widely used language in the world, was undoubtedly the most popular language. Herring JA, who acted as both the corresponding and first author, has contributed to the most co-cited papers published. The most number of LCPD papers are published in the Journal of Pediatric Orthopaedics, whereas the Journal of Bone and Joint Surgery American Volume garnered the highest total citations, indicating the great importance of these two journals in the field of orthopedics. The most frequently used keywords in published articles were related to the symptoms, mechanisms, and prognosis, revealing the research focus of most scholars.

Conclusion

Our research described the development trends and hotspots in the research field of LCPD and will help researchers make better decisions.

Positive outcome reporting in orthopaedic literature

Aims

Perthes' disease (PD) is a relatively rare syndrome of idiopathic osteonecrosis of the proximal femoral epiphysis. Treatment for Perthes' disease is controversial due to the many options available, with no clear superiority of one treatment over another. Despite having few evidence-based approaches, many patients with Perthes' disease are managed surgically. Positive outcome reporting, defined as reporting a study variable producing statistically significant positive (beneficial) results, is a phenomenon that can be considered a proxy for the strength of science. This study aims to conduct a systematic literature review with the hypothesis that positive outcome reporting is frequent in studies on the treatment of Perthes' disease.

Methods

We conducted a systematic review of all available abstracts associated with manuscripts in English or with English translation between January 2000 and December 2021, dealing with the treatment of Perthes' disease. Data collection included various study characteristics, surgical versus non-surgical management, treatment modality, mean follow-up time, analysis methods, and clinical recommendations.

Results

Our study included 130 manuscripts. Overall, 110 (85%) reported positive (beneficial) results, three (2%) reported negative results, and 17 (13%) reported no significant difference. Despite only 10/130 studies (8%) having a testable hypothesis, 71 (55%) recommended the use of their studied treatment methods for the patients, five (4%) made recommendations against the use of the studied treatment modality, and 54 (42%) did not make any recommendations.

Conclusion

The overall rate for positive outcomes among included manuscripts regarding different treatment methods for Perthes' disease (85%) is higher than the 74% positive outcome rate found among studies for other surgically treated disorders and significantly higher than most scientific literature. Despite the lack of testable hypotheses, most manuscripts recommended their studied treatment method as a successful option for managing patients solely based on the reporting of retrospective data.

Functional adaptation after femoral intertrochanteric valgus osteotomy in Legg-Calvé-Perthes disease

Legg-Calvé-Perthes disease (LCPD) requires individualized treatment in order to regain a functional hip joint. In severe cases, in which a congruent joint cannot be achieved, other options are necessary in order to improve functionality and prevent early osteoarthritis. Therefore, we analysed the clinical and radiologic outcome of 28 patients after valgus osteotomy of the proximal femur (VOF). We examined the range of hip motion, functionality and health-related quality of life (HRQoL) via modified Harris Hip Score (mHHS) and Kidscreen-10. Radiographic analysis contained quantitative and qualitative measurements of hip morphology. In particular, we correlated the results with the change of the pelvic-femoral angle (PFA). PFA was defined as the angle between the anatomical diaphyseal line of the femur and a vertical line through the pelvis. The mean follow-up was 5.5 years. Patients showed high mHHS and good HRQoL postoperatively. An increase in ROM with an improvement of 30.5° abduction and 10.3° internal rotation was evident. PFA correlated with adduction contracture and improved significantly after surgery. In consideration of careful patient selection, VOF showed a positive effect on ROM, pain, HRQoL, radiographic congruence and outcome. We identified the age at surgery and an increasing adduction contracture-objectified by a decreased PFA-as a prognostic factor.

Epidemiology, natural evolution, pathogenesis, clinical spectrum, and management of Legg-Calvé-Perthes

Background

Legg-Calvé-Perthes disease is a self-limiting disorder that develops in children following interruption of the blood supply to the capital femoral epiphysis. This review outlines the current knowledge on the epidemiology, natural evolution, clinical spectrum, and management of the disease.

Methods

The literature pertaining to these aspects of the disease were studied and summarized in this review.

Results

Epidemiological studies suggest that environmental factors contribute to the causation of the disease. Incidence rates monitored over time indicate that the incidence of Legg-Calvé-Perthes disease is declining. The natural evolution followed on sequential plain radiographs enables division of the disease into Stages Ia, Ib, IIa, IIb, IIIa, IIIb, and IV. Reversible deformation of the capital occurs in Stages Ia-IIa simply on standing while irreversible deformation may occur in Stages IIb and IIIa. Treatment of Legg-Calvé-Perthes disease in Stages Ia-IIa aims to prevent the femoral head from getting deformed by containment and avoidance of weight-bearing. In Stages IIb and IIIa, treatment aims to remedy the effects of early irreversible deformation of the femoral head. In Stage IIIb and IV, treatment is directed to correcting the altered shape of the femoral head. The impression that these treatment methods are helpful is based on poor quality evidence.

Conclusion

There is an urgent need to undertake Level I studies to establish the efficacy of currently treatment.

Level of evidence

level V.

Does transepiphyseal drilling and closure of the greater trochanter in early Legg-Calve-Perthes disease improve natural history?

PURPOSE

There is no consensus regarding treatment of Legg-Calve-Perthes disease (LCPD). The most common sequel of the disease is coxa breva and overgrowth of the greater trochanter (GT). Our purpose was to examine the effectiveness of transepiphyseal drilling combined with closure of the GT apophysis in patients with LCPD.

METHODS

During 2013-2018, we treated 16 consecutive cases of LCPD. Average age was 7.5 (range 6-10) years; nine patients were in early fragmentation, five in late fragmentation and one in reossification stages. Treatment protocol included hip arthrography, percutaneous drilling of the femoral head epiphysis, percutaneous tenotomy of adductor longus and epiphysiodesis of the GT apophysis.

RESULTS

Mean follow-up was 38 months. One patient was lost to follow-up. All patients had a limp prior to surgery. However, at latest follow-up, 10/15 patients had no limp, 11 patients had substantial improvement in hip range of motion. On radiographs, nine patients had Stulberg type 1-2, one type 3 and five type 4-5. There was no change in the epiphysio-trochanteric distance in any patient. Eight out of nine patients treated in the early fragmentation stage had good clinical and radiographic outcome. Most patients treated in late fragmentation stage had Stulberg 4-5 hip and required additional procedures.

CONCLUSIONS

Based on our preliminary experience, our protocol can be effective in the treatment of patients with LCPD in the initial or early fragmentation stages by improving the clinical and radiographic outcomes of the disease. This minimally invasive approach does not compromise any future treatment options.

LEVEL OF EVIDENCE

IV.

Long-Term Outcomes at Skeletal Maturity of Combined Pelvic and Femoral Osteotomy for the Treatment of Legg-Calve-Perthes Disease

Surgical treatment for Legg-Calve-Perthes disease (LCPD) is recommended for older children with moderate to severe disease. We sought to determine whether double osteotomies lead to improved radiologic outcomes compared to reported non-operative outcomes. Patients older than 6 years of age diagnosed with LCPD lateral pillar B or C who were treated with pelvic and femoral osteotomies were included. Radiologic outcomes and leg-length discrepancies were assessed using the Stulberg classification and were compared with the current literature. Fifteen hips in fourteen patients were treated with double osteotomy for LCPD, and seven had lateral pillar C disease (47%). The mean age at surgery was 8.6 years (range, 7.2-10.4) and the mean age at follow-up was 20.2 years (range, 14.2-35.6). At a mean 11.6-year follow-up (range: 6.3-25.2), double osteotomy resulted in 40% of patients having Stulberg I/II scores, 27% having Stulberg III scores, and 33% having Stulberg IV/V scores. The mean leg-length discrepancy was 1.4 cm in lateral pillar C patients compared to 0.8 cm in lateral pillar B patients. Four patients underwent additional surgeries, including two who required total hip arthroplasty. Double osteotomy as an alternative surgical procedure for the treatment of LCPD did not show improved outcomes when compared to historic non-operative cohorts.

Prognostic value of bone resorption pattern in the anterior portion of the femoral head in Legg-Calvé-Perthes disease

Purpose

To examine whether differences in bone resorption patterns in the anterior portion of the femoral head correlate with the prognosis of Legg-Calvé-Perthes disease.

Methods

Seventy-eight patients with unilateral Legg-Calvé-Perthes disease, who were diagnosed after 6.0 years of age, underwent the Salter innominate osteotomy from 1987 to 2013, and were followed up to skeletal maturity. The anterior bone resorption pattern of the femoral head was evaluated from a frog-leg lateral hip radiograph made in the middle of the fragmentation period, and classified into two types, an epiphysis-preserved type (P) and a physis-disrupted type (D). The correlation between the type of bone resorption and the Stulberg outcome was analyzed.

Results

The Stulberg outcomes were grade I for 9 patients, grade II for 31, grade III for 35, and grade IV for 3, with a mean follow-up period of 8.3 ± 2.7 years. Fifty-one patients demonstrated the type P hips and 27 did the type D hip. In a subset analysis of patients with the modified lateral pillar group-B hips in the younger group (6.0-8.9 years of age at diagnosis), the percentages of the favorable and unfavorable outcomes significantly differed between the two types (p = 0.013). Anteroposterior enlargement of the affected femoral head was significantly greater in the type D hips than the type P hips (p = 0.014).

Conclusion

Unfavorable hip morphology at skeletal maturity can be predicted in patients with the lateral pillar group-B hips by focusing on bone resorption patterns of the anterior portion of the femoral head.

Level of evidence

Level III, prognostic study.

An AI based classifier model for lateral pillar classification of Legg-Calve-Perthes

We intended to compare the doctors with a convolutional neural network (CNN) that we had trained using our own unique method for the Lateral Pillar Classification (LPC) of Legg-Calve-Perthes Disease (LCPD). Thousands of training data sets are frequently required for artificial intelligence (AI) applications in medicine. Since we did not have enough real patient radiographs to train a CNN, we devised a novel method to obtain them. We trained the CNN model with the data we created by modifying the normal hip radiographs. No real patient radiographs were ever used during the training phase. We tested the CNN model on 81 hips with LCPD. Firstly, we detected the interobserver reliability of the whole system and then the reliability of CNN alone. Second, the consensus list was used to compare the results of 11 doctors and the CNN model. Percentage agreement and interobserver analysis revealed that CNN had good reliability (ICC = 0.868). CNN has achieved a 76.54% classification performance and outperformed 9 out of 11 doctors. The CNN, which we trained with the aforementioned method, can now provide better results than doctors. In the future, as training data evolves and improves, we anticipate that AI will perform significantly better than physicians.

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.

Pedicled iliac bone flap grafting in the treatment of late presentation Legg–Calvé–Perthes disease

Background

Legg–Calvé–Perthes disease (LCPD) is a juvenile form of ischemic femoral head osteonecrosis affecting children. The lack of effective and timely treatment results in severe sequelae in children (especially older ones). Although LCPD has been widely studied, little is known about its etiology. As a result, its clinical management is still challenging. This study will investigate the clinical and radiological results of patients older than 6 years and treated with pedicled iliac bone flap grafting for LCPD.

Materials and methods

A total of 13 patients (13 hips) with late presentation of LCPD were treated with pedicled iliac bone flap grafting. Of the 13 patients, 11 were male and 2 were female. The average age of the patients was 8.4 years (range 6–13). Preoperational radiographs and pain scores were analyzed for lateral pillar classification and the Oucher scale. The final follow-up radiograph was classified using a modified Stulberg classification. Limping, extremity length inequality, and range of motion were clinically assessed.

Results

The average follow-up of the patients was 70 months (range 46–120). During the surgery, seven hips were found to be lateral pillar grade B, two were grade B/C, and four were grade C. In the final examination, 12 hips were evaluated as good (Stulberg class I or II) and one as medium (Stulberg class III). There was limb shortening in one patient who was Stulberg class III. There was a significant difference between the preoperational and postoperational radiographic values and the Ocher scale, regardless of the surgical staging (P &lt; 0.05).

Conclusions

Pedicled iliac bone flap graft can treat LCPD accompanied by pain and lateral pillar stage B, B/C, and C in children over 6 years.

Level of Evidence

Level IV—case series.

Platelet to lymphocyte ratio was a risk factor in Perthes disease

The study was aimed to determine the relationship between PLR (platelet to lymphocyte ratio) and the lateral pillar classification of Perthes disease, and to provide an alternative index for clinical diagnosis. In addition, the association of the PLR with the necrosis stage of Perthes disease was also explored. This was a retrospective study. 74 children with Perthes disease and 60 children in the healthy control group without femoral head necrosis in our hospital from 2012 to 2021 were collected. The general data and clinical parameters were collected from the hospital information system. The modified herring lateral pillar classification was collected for the fragmentation stage case group and the PLR, NLR (neutrophil to lymphocyte ratio), LMR (lymphocyte to monocyte ratio) and PNR (platelet to neutrophil ratio) were calculated. The cases were divided into four groups, herring A and B were group I, herring B/C and C were group II, the healthy control group was group III, and the necrosis stage was group IV. The hematological indexes (NLR, PLR, LMR, PNR) of children at different stages were statistically analyzed. Group I consisted of 36 patients, with an average age of 7.4 ± 2.0 years (3-11 years). Group II consisted of 23 patients, with an average age of 7.4 ± 1.9 years (4-12 years). Group III consisted of 60 patients, with a mean age of 7.4 ± 2.7 years (4-13 years). Group IV consisted of 15 patients, with an average age of 6.4 ± 1.7 years (3-10 years). The average values of PLR in groups I, II, III and IV were 131.98 ± 47.44, 122.19 ± 37.88, 102.46 ± 30.68 and 128.90 ± 28.11, respectively. It's worth noting that there was statistically significant difference among groups I, II and III (P = 0.003). The optimal threshold of PLR was 130.25, the sensitivity was 45.8% and the specificity was 85%. PLR was also significantly different between groups III and group IV. PLR was higher in Herring A and B classifications than in Herring B/C and C classifications. PLR had certain diagnostic value in both the necrosis stage and fragmentation stage as a risk factor.

Long-term clinical and radiological outcome in patients with severe Legg-Calvé-Perthes disease after Chiari pelvic osteotomy: a mean of 14 years follow-up

INTRODUCTION

The Chiari pelvic osteotomy (CPO) has been recommended as a salvage procedure to improve head coverage in case of hip joint incongruence in paediatric hip disease. In this study, we aimed to assess the long-term results of CPO for severe Legg-Calvé-Perthes disease (LCPD).

METHODS

A total of 39 patients who underwent a CPO at our department between 1995 and 2010 were prospectively followed both radiologically (Stulberg classification) and clinically (Harris Hip Score [HHS], conversion into total hip arthroplasty). In this study, we retrospectively reviewed the cases of 12 hips (12 patients, 3 girls, 8 left hips) treated by CPO for severe LCPD (Catterall grade 3 or 4) with hip joint incongruence. Mean follow-up was 14.0 (range 7.6-21.3) years.

RESULTS

Mean age at surgery was 10.2 (range 8.2-17.8) years. Additional femoral osteotomy was performed in 8 patients. A good radiological result (Stulberg I or II) was achieved in 2 patients, a fair result (Stulberg III) in 4 patients, and a poor outcome (Stulberg IV or V) in 6 patients. Mean postoperative HHS averaged 93 (range 65-100) points. An excellent functional outcome (HHS 90-100 points) was achieved in 9 patients. No patient underwent total hip arthroplasty during follow-up. Postoperative limb-length discrepancy was found in 3 patients.

CONCLUSIONS

CPO for severe LCPD with hip joint incongruence resulted in good long-term clinical outcome in about ⅔ of our patients after a mean of 14 years. Our results suggest that CPO can still be considered as a salvage joint-conserving procedure in this selected group of younger patients.

Mid–Long-Term Outcomes of Surgical Treatment of Legg-Calvè-Perthes Disease: A Systematic Review

Background: Legg–Calvè–Perthes disease (LCPD) is a common childhood disease that usually occurs in 4- to 12-year-old children. Surgical treatment consists of femoral, pelvic, or combined osteotomies. This comprehensive review aimed to investigate the mid- and long-term outcome of the surgical treatment. Methods: A systematic review of PubMed, Science Direct, and MEDLINE databases was performed by two independent authors, using the keywords “outcome”, “surgical treatment”, “pelvic osteotomy”, “femoral osteotomy”, and “Legg–Calvè–Perthes disease” to evaluate studies of any level of evidence that reported the surgical outcome of LCPD. The result of every stage was reviewed and approved by two senior investigators. Results: A total of 2153 articles were found. At the end of the screening, we selected 23 articles eligible for full-text reading according to the inclusion and exclusion criteria. Our analysis showed that the main prognostic factors for surgical outcome in patients with LCPD are the age at onset and the degree of initial disease severity. Conclusions: Surgical treatment in patients older than 6 years has excellent results in Herring B and B/C hips and poor results in Herring C hips, with a slight advantage for patients between 6 and 8 years old.

Fate of hips complicated by avascular necrosis of the femoral head following reconstructive surgery in nonambulatory patients with cerebral palsy

The purpose of this study was to evaluate the influence of avascular necrosis of the femoral head (AVN) following hip reconstructions on the future hip development of cerebral palsy (CP) patients. A retrospective study of 394 hips in 205 nonambulatory patients with spastic CP who underwent reconstructive hip surgery was performed. The mean age at surgery was 7.3 ± 2.4 years. The mean follow-up duration was 5.6 ± 2.7 years, and the mean age at the latest follow-up was 12.8 ± 3.4 years. AVN was classified in terms of its severity and location. Femoral head remodelling was assessed by the spherical index and the Mose circle. An unsatisfactory radiological outcome was defined as having a migration percentage of more than 30% at the final follow-up. AVN was observed in 169 (42.9%) hips. Older age at the time of surgery, higher preoperative migration percentage, and open reduction procedures were predictors for the development of AVN. Hips with AVN confined to the lateral epiphysis, and AVN involving the entire epiphysis with preserved height experienced successful remodelling. 27 (65.9%) of the 41 hips with unsatisfactory outcomes experienced AVN. Younger age, higher postoperative migration percentage, and occurrence of AVN were related to unsatisfactory outcomes. The highest incidence of failed remodelling and unsatisfactory outcomes were observed in hips with entire epiphyseal involvement and more than 50% loss of its height. AVN following hip reconstructions is not necessarily associated with poor hip development, however, depending on the severity and location, it is a prognostic factor for unsatisfactory radiological outcomes.

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.

Validation of the height-width measurement in Perthes disease among interpreters of different experience levels

The epiphyseal height and metaphyseal width ratio estimated lateral pillar involvement with limited generalizability among various interpreters. The aim of the study was to evaluate the reliability and the validity of height-width ratio measurement in Perthes disease among interpreters of different experience levels. A cross-sectional study was conducted between 2019 and 2020. We included four groups of interpreters: orthopaedic residents, orthopaedic fellows, radiology residents and radiology fellows who were unaware of radiographic study materials. Each interpreter blindedly evaluated Perthes hip radiographs twice at 1-month intervals using the height-width ratio method. Patients' and interpreters' characteristics, height-width ratio and height-width ratio converted to lateral pillar classification (A, B and C) were collected. Intra- and interobserver reliability validated with the paediatric orthopaedist were estimated. Twenty-four interpreters assessed 18 Perthes radiographs. Intraobserver level of agreement (95% confidence interval) for height-width ratio was 0.022 (-0.017 to 0.062), -0.027 (-0.074 to 0.019), -0.010 (-0.095 to 0.074) and 0.019 (-0.109 to 0.146); and interobserver reliability compared with the paediatric orthopaedist was -0.007 (-0.091 to 0.077), 0.003 (-0.056 to 0.061), -0.021 (-0.077 to 0.035) and -0.002 (-0.090 to 0.086) for orthopaedic residents and fellows, radiology residents and fellows, respectively. Kappa statistics of height-width ratio converting to lateral pillar classification indicated intraobserver agreement of orthopaedic residents and fellows, radiology residents and fellows was 0.83, 0.75, 0.54 and 0.91; and interobserver agreement compared with the paediatric orthopaedist was 0.92, 0.83, 0.42 and 0.83, orderly. Height-width ratio and lateral pillar estimation by orthopaedic and radiology trainees have moderate to excellent reliability. Level of evidence: Level II - diagnostic study.

Evaluation of the short-term curative effect of closed reduction in the treatment of developmental dysplasia of the hip based on three-dimensional magnetic resonance imaging finite element analysis

Background

Based on the Digital Imaging and Communications in Medicine (DICOM) data of three-dimensional magnetic resonance imaging (3D-MRI), finite element models of the hip joints of children with developmental dysplasia of the hip were established. The primary objectives included simulation and analysis of the finite element model pre- and post-closed reduction under different stances and loads, and evaluation of the size and distribution of von Mises stress in the acetabulum and femoral head pre- and post-operation and the short-term effects.

Methods

Acetabular index measurements of both the unaffected and affected sides were conducted, alongside International Hip Dysplasia Institute (IHDI) classification of the affected hip. Establishing the finite element model of both the affected and unaffected hips was based on the 3D-T1WI sequence DICOM data, using Mimics, 3-matic, and Ansys software, before and after closed reduction surgery. The size and distribution data of von Mises stress on the affected side of the acetabulum and femoral head were collected pre- and post-operation.

Results

The study indicated that the increasing acetabular index of the affected hip was directly proportional to the increasing severity based on IHDI classification (P < 0.05). Preoperative IHDI classification significantly correlated with the von Mises stress (r = 0.560–0.569, 0.562–0.564, P < 0.05). Under different stances and load conditions, the von Mises stress on the affected side post-operation was lower than that noted pre-operation (P < 0.01), while that on the acetabulum increased proportionally to the load. Although the magnitude and distribution of von Mises stress on the affected side of the acetabulum were similar to those on the healthy side post-operation, there were statistical differences between the two (P < 0.01). The von Mises stress of the lateral column of the femoral head post-operation was significantly lower than that noted pre-operation (P < 0.01). While the high-stress points of the lateral column disappeared post-operation, the von Mises stress was evenly distributed in the femoral head.

Conclusions

The 3D-MRI finite element could provide the von Mises stress value and distribution characteristics of the acetabulum and femoral head pre- and post-operation. Closed reduction can, therefore, improve the size and distribution of von Mises stress on the affected acetabulum and femoral head.

Combined Surgical Dislocation and Periacetabular Osteotomy for Complex Residual Legg-Calvé-Perthes Deformities: Intermediate-Term Outcomes

BACKGROUND

Residual Legg-Calvé-Perthes (LCP) deformities represent one of the most challenging disorders in hip reconstructive surgery. In complex cases, both instability (acetabular dysplasia) and multifocal femoroacetabular impingement (FAI) (proximal femoral deformities) require correction. We assessed intermediate-term patient-reported outcome measures, radiographic correction, complications, and survivorship for combined surgical dislocation (SD) and periacetabular osteotomy (PAO) for the treatment of complex LCP deformities.

METHODS

A retrospective cohort study was performed on 31 hips with complex LCP deformities undergoing combined SD and PAO for concurrent instability and FAI. Treatment included femoral head reshaping, trochanteric advancement and relative femoral neck lengthening, management of intra-articular lesions, and PAO. Twenty-seven hips (87%) had a minimum follow-up of 5 years. The mean age was 19.8 years, 56% of patients were female, and 44% of patients had undergone a previous surgical procedure.

RESULTS

At a mean of 8.4 years, 85% of hips (23 of 27) remained preserved (no conversion to total hip arthroplasty). The survivorship estimates were 93% at 5 years and 85% at 10 years. The median (and interquartile range) increased from 64 points (55, 67 points) to 92 points (70, 97 points) (p < 0.001) for the modified Harris hip score (mHHS) and from 60 points (45, 75 points) to 86 points (75, 100 points) (p = 0.001) for the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain score. Symptoms (mHHS < 70 points) were reported for an additional 19% of hips (n = 5) at the final follow-up. The University of California Los Angeles (UCLA) activity score increased from a median of 8 points (6, 10 points) to 9 points (7, 10 points) (p = 0.207). Structural correction included mean improvement (and standard deviation) of 15.3° ± 7.6° for acetabular inclination, 20.7° ± 10.8° for the lateral center-edge angle, 23.4° ± 16.3° for the anterior center-edge angle, and 18 ± 10 mm for trochanteric height (p < 0.001 for all). Complications occurred in 2 hips (7%), including 1 deep wound infection and 1 superficial wound infection. There was 1 reoperation due to complication, but there were no nerve palsies, thromboembolic events, fractures, or nonunions.

CONCLUSIONS

At an intermediate follow-up of combined SD and PAO for complex LCP deformities, 85% of hips were preserved. This procedure provides reliable deformity correction, major pain relief, improved function, and acceptable complication and failure rates.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Prolonged non-weightbearing treatment decreases femoral head deformity compared to symptomatic treatment in the initial stage of Legg-Calvé-Perthes disease

The purpose of this study is to investigate the potential benefit of using prolonged non-weightbearing (PNWB) as a treatment option for early-stage Legg-Calvé-Perthes disease (LCPD). An Institutional Review Board (IRB) approved this retrospective study of patients with LCPD and ≥2-year follow-up. Patients 6-12 years of age were included if treatment began in Waldenstrom stage 1 or 2A. PNWB consisted of ≥6 months of non- or toe-touch weightbearing. PNWB was recommended if perfusion MRI demonstrated ≥40% hypoperfusion of the femoral head and parents decided against operative treatment. The control group consisted of symptomatically treated patients. Deformity index and epiphyseal quotient were measured at 2-year follow-up. Stulberg classification and sphericity deviation score (SDS) were determined at skeletal maturity or at a minimum of 5-year follow-up. When treatment was initiated in Waldenstrom stage 1, the PNWB group had significantly less femoral head deformity, including deformity index (0.21 vs. 0.52; P < 0.001), epiphyseal quotient (69% vs. 43%; P < 0.001), SDS (18 vs. 52; P = 0.004), and Stulberg (50% good vs. 0% good; P = 0.044). The PNWB group mean hypoperfusion was 68%, indicating severe hypoperfusion. Duration of recommended non-weight bearing in the PNWB group was 11.5 months (range 7-17 months). Despite severe femoral head hypoperfusion, PNWB begun during the initial stage of LCPD decreased femoral head deformity. PNWB should be considered a treatment option for patients/parents who do not wish to pursue operative intervention in early-stage LCPD with substantial hypoperfusion. Level of Evidence III - retrospective comparative study.

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 British Orthopaedic Surgery Surveillance study: Perthes' disease: the epidemiology and two-year outcomes from a prospective cohort in Great Britain

Aims

The aim of this study was to evaluate the epidemiology and treatment of Perthes’ disease of the hip.

Methods

This was an anonymized comprehensive cohort study of Perthes’ disease, with a nested consented cohort. A total of 143 of 144 hospitals treating children’s hip disease in the UK participated over an 18-month period. Cases were cross-checked using a secondary independent reporting network of trainee surgeons to minimize those missing. Clinician-reported outcomes were collected until two years. Patient-reported outcome measures (PROMs) were collected for a subset of participants.

Results

Overall, 371 children (396 hips) were newly affected by Perthes’ disease arising from 63 hospitals, with a median of two patients (interquartile range 1.0 to 5.5) per hospital. The annual incidence was 2.48 patients (95% confidence interval (CI) 2.20 to 2.76) per 100,000 zero- to 14-year-olds. Of these, 117 hips (36.4%) were treated surgically. There was considerable variation in the treatment strategy, and an optimized decision tree identified joint stiffness and age above eight years as the key determinants for containment surgery. A total of 348 hips (88.5%) had outcomes to two years, of which 227 were in the late reossification stage for which a hip shape outcome (Stulberg grade) was assigned. The independent predictors of a poorer radiological outcome were female sex (odds ratio (OR) 2.27 (95% CI 1.19 to 4.35)), age above six years (OR 2.62 (95% CI (1.30 to 5.28)), and over 50% radiological collapse at inclusion (OR 2.19 (95% CI 0.99 to 4.83)). Surgery had no effect on radiological outcomes (OR 1.03 (95% CI 0.55 to 1.96)). PROMs indicated the marked effect of the disease on the child, which persisted at two years.

Conclusion

Despite the frequency of containment surgery, we found no evidence of improved outcomes. There appears to be a sufficient case volume and community equipoise among surgeons to embark on a randomized clinical trial to definitively investigate the effectiveness of containment surgery.

Cite this article: Bone Joint J 2022;104-B(4):510–518.

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.

Predictive ability of inflammatory markers and laboratory parameters in Legg-Calvé-Perthes disease: A single-center retrospective comparative study

ABSTRACT

Legg-Calvé-Perthes disease (LCPD) presents with chronic nature of inflammation, characterized by prolonged synovitis. So far, no single blood marker has been identified to guide clinicians in estimating the severity and prognosis. Blood neutrophil to lymphocyte ratio (NLR) or systemic immune inflammation index (SII) is a simple indicator of subclinical inflammation. This study aims to examine the predictive ability of NLR, SII, and common laboratory parameters for estimating the severity of LCPD. The pre-operative laboratory findings at the time of osteotomy and implant removal in patients with unilateral LCPD who had been treated with the Salter innominate osteotomy and followed up until skeletal maturity as well as those of age-matched control patients with idiopathic noninflammatory conditions were analyzed. The datasets of 26 or 38 LCPD patients at the time of osteotomy or implant removal, respectively, and those of 20 control patients were available for analysis. At the time of osteotomy, compared to the control group, a significantly higher mean NLR or SII and a significantly lower mean alkaline phosphatase value were observed in the LCPD group. The alkaline phosphatase levels of patients with the modified lateral pillar (LP) group-A hips were significantly lower than those with the non-LP-A hips, whereas no significant differences were observed in any of the parameters between patients with favorable LP-A or -B hips and those with unfavorable LP-B|C border or -C hips. In agreement with the conventional opinion, it may be difficult to predict a meaningful prognosis of LCPD with the use of inflammatory markers or common laboratory parameters obtained in the initial stage of the disease.

Legg-Calvé-Perthes disease overview

Background

Legg–Calvé–Perthes Disease (LCPD) is a necrosis of the femoral head which affects the range of motion of the hips. Its incidence is variable, ranging from 0.4/100,000 to 29.0/ 100,000 children. Although LCPD was first described in the beginning of the past century, limited is known about its etiology. Our objective is to describe the main areas of interest in Legg–Calve–Perthes disease.

Methods

A review of the literature regarding LCPD etiology was performed, considering the following inclusion criteria: Studies reporting clinical or preclinical results. The research group carried out a filtered search on the PubMed and Science Direct databases. To maximize the suitability of the search results, we combined the terms ‘‘Perthes disease” OR “LCPD” OR “children avascular femoral head necrosis” with “diagnostic” OR “treatment” OR “etiology” as either key words or MeSH terms.

Results

In this article been described some areas of interest in LCPD, we include topics such as: history, incidence, pathogenesis, diagnosis, treatment and possible etiology, since LCPD has an unknown etiology.

Conclusions

This review suggests that LCPD has a multifactorial etiology where environmental, metabolic and genetic agents could be involved.

The modified Stulberg classification is a strong predictor of the radiological outcome 20 years after the diagnosis of Perthes' disease

AIMS

The aim of this study was to assess the prognostic value of the modified three-group Stulberg classification, which is based on the sphericity of the femoral head, in patients with Perthes' disease.

METHODS

A total of 88 patients were followed from the time of diagnosis until a mean follow-up of 21 years. Anteroposterior pelvic and frog-leg lateral radiographs were obtained at diagnosis and at follow-up of one, five, and 21 years. At the five- and 21-year follow-up, the femoral heads were classified using a modified three-group Stulberg classification (round, ovoid, or flat femoral head). Further radiological endpoints at long-term follow-up were osteoarthritis (OA) of the hip and the requirement for total hip arthroplasty (THA).

RESULTS

There were 71 males (81%) and 17 females. A total of 13 patients had bilateral Perthes' disease; thus 101 hips were analyzed. At five-year follow-up, 37 hips were round, 38 ovoid, and 26 flat. At that time, 66 hips (65%) were healed and 91 (90%) were skeletally immature. At long-term follow-up, when the mean age of the patients was 28 years (24 to 34), 20 hips had an unsatisfactory outcome (seven had OA and 13 had required THA). There was a strongly significant association between the modified Stulberg classification applied atfive-year follow-up and an unsatisfactory outcome at long-term follow-up (p < 0.001). Between the five- and 21-year follow-up, 67 hips (76%) stayed in their respective modified Stulberg group, indicating a strongly significant association between the Stulberg classifications at these follow-ups (p < 0.001).

CONCLUSION

The modified Stulberg classification is a strong predictor of long-term radiological outcome in patients with Perthes' disease. It can be applied at the healing stage, which is usually reached five years after the diagnosis is made and before skeletal maturity. Cite this article: Bone Joint J 2021;103-B(12):1815-1820.

Results of Early Proximal Femoral Osteotomy at Skeletal Maturity in Legg-Calvé-Perthes Disease: Implication for the Bypass of Fragmentation Stage

BACKGROUND

The aim was to assess the long-term radiographic outcomes of patients with Legg-Calvé-Perthes disease following an early proximal femoral osteotomy (PFO) performed in avascular necrosis stage or early fragmentation stage.

METHODS

In this retrospective study, we analyzed data of 65 patients aged above 6 years at the time of diagnosis with unilateral Legg-Calvé-Perthes disease, following early PFO performed at our institution between 1979 and 2013. We observed the presence of bypassing fragmentation stage, which was classified into complete and incomplete. We compared radiographic outcomes between patients with bypass of fragmentation stage (26 hips) and those without (31 hips). Regarding skeletal maturity, the hips were graded according to the femoral head shapes: spherical, ovoid, or flat.

RESULTS

The mean age at diagnosis was 7.9 years (range: 6.0 to 11.9 y). The average follow-up period was 11.8 years (range: 5.9 to 22.9 y). Fragmentation bypass occurred in 40.5% (26/65) of patients, with 8 (12.3%) "undetermined" cases. Patients who completely or partially bypassed fragmentation experienced significantly less severe lateral pillar collapse (P=0.016). The femoral head was also significantly more spherical in patients with bypass (P=0.024).

CONCLUSIONS

Our results show that 40.5% of patients who underwent early PFO bypassed the fragmentation stage. The degree of lateral pillar collapse was lower in patients with bypass. In addition, there were significantly more patients with more spherical femoral head in the bypass group.

LEVEL OF EVIDENCE

Level IV-case series.

How does former Salter innominate osteotomy in patients with Legg–Calvé–Perthes disease influence acetabular orientation? An MRI-based study

Salter innominate osteotomy (SIO) has been successfully used in the treatment of Legg–Calvé–Perthes disease (LCPD). Recent studies that have raised concerns about acetabular retroversion after SIO have been based on plain radiographs. In order to assess the true acetabular orientation, the present study uses a specific magnetic resonance imaging (MRI) technique. In addition, the association between acetabular morphology and clinical function as well as health-related quality of life was assessed. Twenty-three patients with 24 operated hips who underwent SIO for LCPD between January 2004 and November 2014 were included. Mean age was 8.5 ± 2.2 years at surgery and 18.5 ± 2.9 years at follow-up. MRIs were conducted at 1.5 T using radial sequences. The analysis included the acetabular version, acetabular sector angles (ASAs) and alpha angles. Plain radiographs were used in order to obtain the Stulberg classification. Patient-related outcome measures included the international Hip Outcome Tool and Euroqol-5 dimensions scores. In comparison to the non-operated side, the MRI of previously operated hips showed no difference of version at the center of the femoral head but significantly decreased version just below the roof level. As a marker for posterior acetabular coverage, the ASAs between 9 and 11 o’clock were significantly decreased when compared with non-operated hips. In hips with a mild acetabular retroversion (<15°), the function was significantly decreased when compared with non-retroverted hips. The SIO is an effective tool in order to restore acetabular containment in LCPD. When compared with the non-operated hips, our collective displays only moderate changes of acetabular orientation and coverage.

PlA2 Polymorphism of Platelet Glycoprotein IIb/IIIa and C677T Polymorphism of Methylenetetrahydrofolate Reductase (MTHFR), but Not Factor V Leiden and Prothrombin G20210A Polymorphisms, Are Associated with More Severe Forms of Legg-Calvé-Perthes Disease

The possible association of common polymorphic variants related to thrombophilia (the rs6025(A) allele encoding the Leiden mutation, rs1799963(A), i.e., the G20210A mutation of the prothrombin F2 gene, the rs1801133(T) variant of the methylenetetrahydrofolate reductase (MTHFR) gene that encodes an enzyme involved in folate metabolism, and rs5918(C), i.e., the ‘A2’ allele of the platelet-specific alloantigen system that increases platelet aggregation induced by agonists), with the risk of Legg–Calvé–Perthes disease (LCPD) and the degree of hip involvement (Catterall stages I to IV) was analyzed in a cohort study, including 41 children of ages 2 to 10.9 (mean 5.4, SD 2.2), on the basis of clinical and radiological criteria of LCPD. In 10 of the cases, hip involvement was bilateral; thus, a total of 51 hips were followed-up for a mean of 75.5 months. The distribution of genotypes among patients and 118 controls showed no significant differences, with a slightly increased risk for LCPD in rs6025(A) carriers (OR: 2.9, CI: 0.2–47.8). Regarding the severity of LCPD based on Catterall classification, the rs1801133(T) variant of the MTHFR gene and the rs5918(C) variant of the platelet glycoprotein IIb/IIIa were associated with more severe forms of Perthes disease (Catterall III–IV) (p < 0.05). The four children homozygous for mutated MTHFR had a severe form of the disease (Stage IV of Catterall) and a higher risk of non-favorable outcome (Stulberg IV–V).

Legg-Calvé-Perthes disease following Ender nail fixation of a pediatric femoral fracture

Introduction and importance

Legg–Calvé–Perthes disease (LCPD) sometimes occur in children, however it is difficult to diagnose it at the early stage especially in the cases there are no complaints of symptoms. Femoral shaft fractures in children cause various complications such as leg-length discrepancy, nonunion and malunion, refracture, and osteonecrosis of the femoral head. We presented a rare case in which a pediatric patient developed LCPD after femoral shaft fracture.

Case presentation

A healthy 8-year-old boy sustained a left femoral diaphyseal fracture following a pedestrian car accident. Fixation was achieved using retrograde Ender nails; bone union was confirmed at 3 months postoperatively, and the Ender nails were removed at 8 months postoperatively without any problems. Unfortunately, the morphological change of the ipsilateral femoral head and subtle symptoms were missed until the femoral head collapsed. LCPD was successfully treated with intertrochanteric varus osteotomy, which achieved a good clinical result.

Clinical discussion

Although the reason for the ipsilateral LCPD after the femoral shaft fracture is unclear, this case highlights the need for close postoperative follow-up of pediatric femoral fractures resulting from high-energy trauma to prevent the misdiagnosis of this coincidental complication.

Conclusion

This case report describes a missed ipsilateral LCPD after a femoral diaphyseal fracture caused by high-energy trauma. Close postoperative follow-up with a detailed assessment and vigilant interpretation of postoperative radiography is imperative to avoid delayed/missed diagnosis of conditions for which early management may provide better outcomes.

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Legg–Calvé–Perthes disease after femoral shaft fracture

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Close postoperative radiographic follow-up is necessary to avoid misdiagnosis.

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Legg–Calvé–Perthes disease was successfully treated with intertrochanteric varus osteotomy.

Surgical Treatments for Legg-Calvé-Perthes Disease: Comprehensive Review

Background

Legg-Calvé-Perthes disease (LCPD) is a common public health problem that usually occurs between the ages of 4 and 8 years, but it can occur between the ages of 2 and 15 years. This condition occurs due to the interruption of blood supply to the femoral head. Up to now, different surgical and nonsurgical treatments, including femoral varus osteotomy, innominate osteotomy, pelvic osteotomies, triple osteotomy, Chiari osteotomy, and shelf acetabuloplasty, have been suggested for noncontainable LCPD hips.

Objective

The aim of this comprehensive review was to investigate the various surgical techniques used for LCPD.

Methods

An advanced electronic search of the English-language literature was performed from October 8 to 14, 2020. The electronic databases PubMed, MEDLINE, Web of Science, Embase, Ovid, and Google scholar were searched using appropriate search terms. A manual search of references also was performed. After retrieving the studies, duplicates were removed, and the remining studies were screened based on the title, abstract, and full text. The quality of the selected articles was assessed, and the required data were extracted from eligible articles.

Results

A total of 22 studies were included in the review. Based on the results of the reviewed studies, there are three main factors that influence the treatment outcomes in patients with Perthes disease. These factors are onset age, femoral head involvement severity, and treatment method. The disease has a poor prognosis in children over 8 years old, but this group of patients can also benefit from advanced surgical methods. In patients aged less than 6 years, the disease has a generally good prognosis, but in those aged between 6 and 8 years, its prognosis is variable. Thus, the need for surgical intervention requires close observation of signs. Once any head signs are observed, dynamic arthrography is beneficial before choosing the treatment approach.

Conclusions

This review provides clinicians with a brief guideline for the treatment of patients with LCPD.

Towards a definition of Ancient Rare Diseases (ARD): Presenting a complex case of probable Legg-Calvé-Perthes Disease from the North Caucasian Bronze Age (2200-1650 cal BCE)

OBJECTIVE

This study discusses the challenges and possibilities of establishing a definition for Ancient Rare Diseases (ARD) in a probable case of Legg-Calvé-Perthes Disease (LCPD) from the Bronze Age cemetery Kudachurt 14, situated in the Northern Caucasus.

MATERIALS

We investigated the skeletal remains of a male aged 35-45 years at death. For comparison we examined other males buried at Kudachurt 14 (n = 24) and reviewed 22 LCPD cases from the paleopathological literature.

METHODS

We use macroscopic as well as osteometric examination methods and imaging techniques.

RESULTS

The morphology of the left hip joint corresponds to skeletal characteristics for LCPD. Co-occurring osteochondrosis dissecans, femoral anteversion, and atrophy of the left femoral shaft suggest a complex disease course.

CONCLUSIONS

Modern criteria of rare diseases applied on ancient skeletal remains are either non-transferable or require completion. We conclude that rarity is dynamic, etiological uncertainty has to be accepted, and the respective socioeconomic context is crucial. Degree of disability and level of sociomedical investment are not defining criteria for ARD.

SIGNIFICANCE

Dating 2200-1650 cal BCE, this study currently presents the earliest case of probable LCPD. This is the first attempt to transform modern characteristics of rare diseases for establishing a paleopathological concept of ARD.

LIMITATIONS

As this study is limited to LCPD, our conclusions are not directly applicable to other ARD in question.

SUGGESTIONS FOR FURTHER RESEARCH

More focused paleopathological research on skeletal populations from different cultures and time periods is needed, enabling an evolutionary perspective on the comparability of ancient, modern and future rare diseases.

Does the Duration of Each Waldenström Stage Affect the Final Outcome of Legg-Calvé-Perthes Disease Onset before 6 Years of Age?

The purpose of this study was to evaluate the outcomes of patients with Legg–Calvé–Perthes disease (LCPD) with disease onset before 6 years of age who were treated with conservative methods and to identify prognostic factors. Moreover, we evaluated the duration of the Waldenström stage and its correlation with the disease outcome. Disease severity was assessed using the lateral pillar classification, and the final outcome was evaluated using the Stulberg classification. We divided patients with LCPD into two groups according to the age at onset: group 1 (<4 years) and group 2 (4–6 years). The final outcomes of the two groups were compared. We also assessed the duration of each Waldenström stage. LCPD was noted in 49 hips of 49 patients. The lateral pillar class was A in one patient, B in 29 patients, and B/C or C in 19 patients. The Stulberg class was I or II (good) in 30 patients, III (fair) in 13 patients, and IV or V (poor) in six patients. The lateral pillar class significantly correlated with the final outcome. Groups 1 and 2 comprised 25 and 24 patients, respectively. The prevalence of good outcomes did not significantly differ between the groups (p = 0.162). The duration of the initial stage was 4.1 months in the good outcome group and 6.2 months in the fair or poor outcome group. The duration of the fragmentation stage of the femoral head was 5.9 months in the good outcome group and 11.9 months in the fair or poor outcome group. The durations of initial and fragmentation stages significantly differed between good outcome group and fair or poor outcome group (p = 0.009 and p < 0.001, respectively). The prognosis of patients with disease onset before the age of 6 years was favorable. The disease severity and duration of each Waldenström stage can be predictors of the outcome. Patients with prolonged initial and fragmentation stages showed worse outcomes and often required more active treatment to shorten the durations of the initial and fragmentation stages.

Reproducibility of Radiographic Measurements Made in the Active Stages of Legg-Calvé-Perthes Disease: Evaluation of a Prognostic Indicator and an Interim Outcome Measure

BACKGROUND

Deformity index (DI) and extrusion index (EI) are 2 radiographic methods currently used to quantify femoral head deformity in the active stages of Legg-Calvé-Perthes disease. This study aimed to quantify the interobserver reproducibility of the 2 methods using a large, international group of pediatric orthopaedic surgeons with diverse clinical experience.

METHODS

Radiographs of patients (age 6 to 11 y at time of diagnosis) prospectively enrolled in an international multicenter-cohort study, were measured by members of our study group. For each radiograph, the raters independently assessed EI (n=33 cases) and DI (n=32 cases), along with the rater's subjective assessment of the extent of hip deformity (ie, none, mild, moderate, or severe). Reliability analysis was conducted using intraclass correlation coefficient (ICC) and κ techniques.

RESULTS

The ICC for EI on the affected side was 0.68 (95% confidence interval: 0.57-0.79). The calculated DI ICC was 0.53 (95% confidence interval: 0.41-0.68). Subjectively, an average of 68±3.5% of surgeons agreed on the subjective description of each patient's femoral head deformity.

CONCLUSIONS

EI is measured with a reasonably high rate of correlation among surgeons from disparate backgrounds. Agreement is lower among the same group of surgeons when the more complex DI is used. DI is most useful when utilized by a small number of experienced observers in a research setting, whereas EI may have better clinical applicability.

LEVEL OF EVIDENCE

Level III-reliability study.

Legg-Calvé-Perthes' disease. Congruent aspherity caused by physeal injury

INTRODUCTION

Perthes disease often produces a congruent nonspherical coxa. The most widely accepted cause is initial bone collapse, but some authors refer to physeal injury as the cause of this deformity. We analyze this elliptical process in cases of congruent nonspherical Perthes.

METHODS

Retrospective case-control study of 49 unilateral class III-IV Perthes cases that were not operated on. Results were compared with 49 healthy contralateral hips. The following radiological variables were determined both in AP and lateral projection, and at 4 points in time of the disease: ovalization index (OI), arthrotrochanteric distance, intraphysial angle, physeal narrowing, presence of double epiphyseal reosification nucleus, physeal length and Reimers index.

RESULTS

The initial OI was 1.7 in the early reosification phase and final OI was 2.07 at physeal closure. The OI in the control cases was invariably 1.4. There was a direct relation between a high index and the initial appearance of a double epiphyseal ossification nucleus, asymmetric physeal effacement and the increase of the intraphyseal angle in both radiographic projections.

CONCLUSIONS

The elliptical process of the femoral head occurs progressively throughout the disease and not only during bone collapse. It starts in the reosification phase and ends when growth stops. The initial risk signs found were the appearance of the double nucleus of reosification, the progressive angulation of the physis and the progressive increase in the rate of ovalization.

Global differences in the treatment of Legg-Calvé-Perthes disease: a comprehensive review

INTRODUCTION

Global discussions regarding the treatment of Legg-Calvé-Perthes disease (LCPD) are still controversial. The aim of this study was to characterize the worldwide regional differences in nonoperative and operative treatment for LCPD.

MATERIALS AND METHODS

Based on a comprehensive literature search, 123 studies describing the results of nonoperative and operative treatment for LCPD were included. Overall, disease and outcome parameters of 6,968 hips were recorded and compared among the continents-Europe, North America, Asia, Africa, South America, and Australia.

RESULTS

Our results showed that the continents differed regarding initial disease progression and therapeutic decision-making, but the final outcome was comparable. The reported proportion of affected hips with mild presentation tended to be higher in Europe, North America, and Africa, whereas disease progression was more severe in Asia, Australia, and South America. Nonoperative treatment was reported more frequently in Europe and North America, while operative management was more common in the rest of the world. Femoral osteotomy was performed more frequently than pelvic osteotomy worldwide, but pelvic osteotomy was comparably more common in North America, Australia, and South America.

CONCLUSIONS

The continents differed in terms of therapies for LCPD, while the final outcome was similar. Studies with greater evidence and larger sample size are needed to evaluate the effect of therapeutic measures on LCPD outcome.

LEVEL OF EVIDENCE

III (systematic review of level III studies).

Legg-Calvé-Perthes disease in a patient with Bardet-Biedl syndrome: A case report of a novel MKKS/BBS6 mutation

This article reports a girl with Bardet-Biedl syndrome (BBS) having a novel causative mutation who developed Legg-Calvé-Perthes disease (LCPD). There exists a possibility that the prognosis of LCPD had been adversely affected by the concomitant BBS.

Reliability of the modified lateral pillar classification for Legg Calvé Perthes disease performed by a large group of international paediatric orthopaedic surgeons

PURPOSE

The modified lateral pillar classification (mLPC) is used for prognostication in the fragmentation stage of Legg Calvé Perthes disease. Previous reliability assessments of mLPC range from fair to good agreement when evaluated by a small number of observers with pre-selected radiographs. The purpose of this study was to determine the inter-observer and intra-observer reliability of mLPC performed by a group of international paediatric orthopaedic surgeons. Surgeons self-selected the radiograph for mLPC assessment, as would be done clinically.

METHODS

In total, 40 Perthes cases with serial radiographs were selected. For each case, 26 surgeons independently selected a radiograph and assigned mLPC and 21 raters re-evaluated the same 40 cases to establish intra-observer reliability. Rater performance was determined through surgeon consensus using the mode mLPC as 'gold standard'. Inter-observer and intra-observer reliability data were analysed using weighted kappa statistics.

RESULTS

The weighted kappa for inter-observer correlation for mLPC was 0.64 (95% confidence interval: 0.55 to 0.74) and was 0.82 (range: 0.35 to 0.99) for intra-observer correlation. Individual surgeon's overall performance varied from 48% to 88% agreement. Surgeon mLPC performance was not influenced by years of experience (p = 0.51). Radiograph selection did not influence gold standard assignment of mLPC. There was greater agreement on cases of mild B hips and severe C hips.

CONCLUSIONS

mLPC has low good inter-observer agreement when performed by a large number of surgeons with varied experience. Surgeons frequently chose different radiographs, with no impact on mLPC agreement. Further refinement is needed to help differentiate hips on the border of group B and C.

LEVEL OF EVIDENCE

III.

Dynamic deformation of the femoral head occurs on weightbearing in Legg-Calves-Perthes disease: a translational pilot study

Aims

Though the pathogenesis of Legg-Calve-Perthes disease (LCPD) is unknown, repetitive microtrauma resulting in deformity has been postulated. The purpose of this study is to trial a novel upright MRI scanner, to determine whether any deformation occurs in femoral heads affected by LCPD with weightbearing.

Methods

Children affected by LCPD were recruited for analysis. Children received both standing weightbearing and supine scans in the MROpen upright MRI scanner, for coronal T1 GFE sequences, both hips in field of view. Parameters of femoral head height, width, and lateral extrusion of affected and unaffected hips were assessed by two independent raters, repeated at a one month interval. Inter- and intraclass correlation coefficients were determined. Standing and supine measurements were compared for each femoral head.

Results

Following rigorous protocol development in healthy age-matched volunteers, successful scanning was performed in 11 LCPD-affected hips in nine children, with seven unaffected hips therefore available for comparison. Five hips were in early stage (1 and 2) and six were in late stage (3 and 4). The mean age was 5.3 years. All hips in early-stage LCPD demonstrated dynamic deformity on weightbearing. Femoral head height decreased (mean 1.2 mm, 12.4% decrease), width increased (mean 2.5 mm, 7.2% increase), and lateral extrusion increased (median 2.5 mm, 23% increase) on standing weightbearing MRI compared to supine scans. Negligible deformation was observed in contra-lateral unaffected hips, with less deformation observed in late-stage hips. Inter- and intraclass reliability for all measured parameters was good to excellent.

Conclusion

This pilot study has described an effective novel research investigation for children with LCPD. Femoral heads in early-stage LCPD demonstrated dynamic deformity on weightbearing not previously seen, while unaffected hips did not. Expansion of this protocol will allow further translational study into the effects of loading hips with LCPD.

Cite this article: Bone Joint Open 2020;1-7:364–369.

Range of abduction in patients with Legg-Calvé-Perthes disease - a nationwide register-based cohort study

BACKGROUND

Range of abduction often decreases during Legg-Calvé-Perthes Disease (LCPD) disease. However, a good range of abduction is required during the course of LCPD, especially when containment surgery should be performed. This study aimed to investigate how many patients registered in the Swedish Pediatric Orthopedic Quality register (SPOQ) with LCPD had reduced range of abduction at diagnosis in relation to sex or age at diagnosis or severity of disease (lateral pillar class at the time at diagnosis), if physiotherapy (PT) was prescribed and has a beneficial impact in maintaining (or increasing) abduction and if the range of abduction at diagnosis before fragmentation stage is predictive for the lateral pillar classification at fragmentation stage.

METHODS

The national Swedish Pediatric Orthopedic Quality Register (SPOQ), established in 2015, is used to identify patients with LCPD. The patients are registered at three time points: at diagnosis, at potential surgery and 2 years after diagnosis. Range of abduction and information on PT are required to register at all registration sessions. One hundred ninety-nine hips from 192 children were registered in the SPOQ.

RESULTS

Of all hips, the mean range of abduction at diagnosis was 39 degrees (range 0 to 90). One hundred twenty-six patients (63%) either received instructions for PT or were referred to a physiotherapist; two patients were treated additionally with an abduction brace. There was a trend that patients who received PT, compared to patients without PT, either maintained or increased their range of abduction at the 2-year follow-up. Older age at diagnosis correlated with decreased range of abduction at the 2-year follow-up (Estimate [Est]: - 3.1, 95% confidence interval [CI]: - 4.4 to - 1.7). The degree of abduction at diagnosis before fragmentation stage correlated with the lateral pillar group at the fragmentation stage (Est: -5.3, 95% CI: - 10.0 to - 1.1).

CONCLUSION

In all, 63% of the children with LCPD in SPOQ received either written instructions or were referred to PT or both. PT seems to have a favorable impact for maintaining the range of abduction in children with LCPD. Children with a lower range of abduction at diagnosis (before the fragmentation stage) developed a higher degree of lateral pillar involvement as measured by the lateral pillar classification.

Comparison of surgical and nonsurgical containment methods for patients with Legg-Calvé-Perthes disease of the onset ages between 6.0 and 8.0 years: Salter osteotomy versus a non-weight-bearing hip flexion-abduction brace

Since bone healing potential decreases with age, patients with Legg-Calvé-Perthes disease should receive treatment appropriate to their age group. Nonsurgical treatment is commonly applied to patients under 6.0 years of age at the onset and surgical treatment is recommended for those over 8.0 years of age, but it remains unclear which is better for those between 6.0 and 8.0 years. The aim of this retrospective study was to compare outcomes of Salter osteotomy and a non-weight-bearing brace in this age group. Inclusion criteria were unilateral Legg-Calvé-Perthes disease patients who were 6.0-8.0 years of age at the onset, who had more than 50% femoral head involvement without hinge abduction, and who underwent either Salter osteotomy (n = 35) or a non-weight-bearing hip flexion-abduction brace (n = 18). Radiological and clinical outcomes at skeletal maturity were compared between the two groups. The mean follow-up durations were 9.4 years in the Salter osteotomy group and 10.0 years in the brace group. There was no significant difference in the modified Waldenström classification at the beginning of treatment and the Catterall and modified lateral pillar classifications evaluated at the fragmentation stage between the groups. At skeletal maturity, the Stulberg classification, the sphericity deviation score, femoral head overgrowth, and the articulo-trochanteric distance were similar between the groups, but the Salter osteotomy group showed significantly smaller lateralization of the femoral head and better acetabular shape and coverage than the brace group: femoral head lateralization (P < 0.001), acetabular depth-to-width ratio (P = 0.002), Sharp angle (P < 0.001), lateral acetabular shape (P = 0.027), acetabular head index (P < 0.001). There was no significant difference in hip pain and motion between the groups. In this age group, Salter osteotomy provides better femoral head position and acetabular shape and coverage than a non-weight-bearing brace.

Does Early Proximal Femoral Varus Osteotomy Shorten the Duration of Fragmentation in Perthes Disease? Lessons From a Prospective Multicenter Cohort

BACKGROUND

The prognosis of Legg-Calvé-Perthes disease (LCPD) is dependent upon several factors, with the length and severity of the fragmentation stage among the most important. Previous retrospectively collected data from a single center have suggested that early proximal femoral varus osteotomy (PFO) may shorten the length of fragmentation and allow 34% of patients to bypass fragmentation altogether resulting in less femoral head deformity. The purpose of this study was to validate these findings in a prospectively collected multicenter cohort.

METHODS

Patients with LCPD treated with early PFO (during Waldenström stage I) were prospectively followed with serial radiographs at 3-month intervals until a minimum of 2-year follow-up. Waldenström stages and lateral pillar class were determined by mode assessments from 3 pediatric orthopaedic surgeons. The duration of fragmentation was defined as the interval between the first radiographs demonstrating features of stage IIa and stage IIIa. "Complete" bypass was defined as the absence of stage IIa or IIb findings on sequential radiographs with no development of femoral head deformity or collapse. "Partial" bypass was defined as the absence of advanced features of fragmentation and femoral head collapse (stage IIb).

RESULTS

Forty-six patients (80% male individuals) with initial stage LCPD and a mean age of 8.2±1.2 years were identified. The weighted kappa statistics for Waldenström staging and lateral pillar classifications showed excellent (0.833) and substantial (0.707) agreement, respectively. Ninety-eight percent of patients (45/46) underwent some period of fragmentation lasting between 91 and 518 days; the median duration was 206 days (interquartile range, 181 to 280). One patient (2%) bypassed fragmentation completely; 8 patients (17%) demonstrated partial bypass. Patients who completely or partially bypassed fragmentation experienced significantly less severe lateral pillar collapse (P=0.016) and shorter fragmentation duration (P=0.001).

CONCLUSIONS

In this prospective multicenter cohort, we found a lower rate of fragmentation bypass than previously reported. Nonetheless, our data support the previous contention that early PFO may shorten fragmentation and minimize collapse in LCPD compared with historical controls. Further study with larger cohorts and a more rigorous definition of what constitutes bypass is warranted to clarify the effect of early PFO on the reparative biology of LCPD.

LEVEL OF EVIDENCE

Level IV-therapeutic study.

The effect of the necrotic area on the biomechanics of the femoral head - a finite element study

Background

Femoral head collapse is the key to the progress of osteonecrosis of the femoral head (ONFH), but the causes of collapse are not completely clear. The better understanding of the progress of femoral head collapse will guide the treatment strategy for ONFH patients. The purpose of this study was to evaluate the biomechanical influence of necrosis area on the collapse of the femoral head by finite element analysis.

Methods

CT and MRI data from the hip joint of a healthy volunteer were collected to establish a finite element (FE) model of a normal hip. Subsequently, five categories of osteonecrosis FE models were established by using the normal model and computer software according to China-Japan Friendship Hospital (CJFH) classification for ONFH. The CJFH system includes five types based on the size and location of necrosis lesions in the femoral head (type M, C, L1, L2, and L3) and the stage of ONFH. The collapse indices of each model were analyzed by FE method, including the displacement, peak von Mises stress and stress index of the simulated necrotic area as well as the lateral pillar contact area of the femoral head to acetabular.

Results

(1) The displacement increments in the simulated necrotic areas of type M, C, L1, L2, and L3 models were 3.75 μm, 8.24 μm, 8.47 μm, 18.42 μm, and 20.44 μm respectively; the peak von Mises stress decrements were 1.50 MPa, 3.74 MPa, 3.73 MPa, 4.91 MPa, and 4.92 MPa respectively; and the stress indices were 0.04, 0.08, 0.08, 0.27, and 0.27 respectively. (2) The displacement increments in the lateral pillar contact areas of five type models were significantly different (P < 0.001) and increased in sequence as follows: 1.93 ± 0.15 μm, 5.74 ± 0.92 μm, 5.84 ± 1.42 μm, 14.50 ± 3.00 μm, and 16.43 ± 3.05 μm. The peak von Mises stress decrements were also significantly different (P < 0.001) and increased in sequence as follows: 0.52 ± 0.30 MPa, 0.55 ± 0.12 MPa, 0.67 ± 0.33 MPa, 4.17 ± 0.59 MPa, and 4.19 ± 0.60 MPa. (3) The collapse indices including the displacement increments and peak von Mises stress decrements of type L2 and L3 models were markedly higher than those of type M, C, and L1 models (P < 0.001).

Conclusions

The collapse indices of the femoral heads of type L2 and L3 FE models were significantly higher than those of type M, C, and L1. Different areas of necrosis result in varied impact on the femoral head collapse.

Diagnostik und Therapie des Morbus Perthes

Die Behandlung des M. Perthes stellt aufgrund der ungeklärten Ätiologie sowie der unterschiedlichen Verlaufsformen und Behandlungskonzepte eine Herausforderung dar. Die Prognose ist abhängig von klinischen und radiologischen Parametern. Aktuelle Behandlungsansätze zielen in frühen Krankheitsstadien auf die Verbesserung der Durchblutung des Femurkopfes und später auf die Vergrößerung des Bewegungsumfangs sowie die Verminderung der vertikal einwirkenden Kräfte durch Teilentlastung und chirurgisch verbesserte Einstellung des Femurkopfes in der Gelenkpfanne ab. Da einerseits ein hoher Prozentsatz an Spontanremissionen ohne Deformitäten des Gelenks, andererseits ein hohes Risiko für eine schwere Koxarthrose mit der Notwendigkeit eines frühen Gelenkersatzes sowohl nach konservativen als auch nach operativen Verfahren zu beobachten sind, werden die Behandlungsmethoden kontrovers diskutiert.

Hip Pain in Children

BACKGROUND

Atraumatic hip pain in children is one of the most common symptoms with which pediatricians, orthopedists, and general practitioners are confronted, with an incidence of 148 cases per 100 000 persons per year.

METHODS

This article is based on publications up to April 2019 that were retrieved by a selective search in the PubMed data- base, including case reports and reviews.

RESULTS

Infants with fever often have purulent coxitis, which can be diagnosed by blood tests and ultrasonography. Toddlers and older children may suffer from painful restriction of motion of the hip joint, associated with limping (antalgic gait) or even the in- ability to walk. The main elements of the differential diagnosis in children aged 2-10 are coxitis fugax and idiopathic necrosis of the femoral head (Perthes disease). In children aged 10 and up, and in adolescents, slipped capital femoral epiphysis (SCFE) is typical. Bone tumors and rheumatic diseases must always be considered as well. The initial diagnostic steps on presentation of a child with restricted hip movement should be plain x-rays and joint ultrasonography for the detection of an effusion. Suspicion of a tumor is the main indication for tomographic imaging (computed tomography or magnetic resonance imaging).

CONCLUSION

The underlying cause of hip pain in children should be diagnosed early to avoid adverse sequelae.

The Importance of Natural History

In a traditional view, the natural history of a condition or a disease tells us of the adult consequences of that entity, be it benign or otherwise. This knowledge then provides guidance as to who needs treatment, and allows us to assess whether our treatments alter an otherwise adverse natural history in a positive way without introducing iatrogenic complications. However, in the new paradigm for health care delivery of value-based care, we need to be able to express natural history in additional terms of burden of disease. This is something that lawmakers and people who pay for health care can understand and has a comparative value. It also serves as a benchmark to show the effectiveness of interventions aimed at reducing disease burden. In this paper, I will discuss why this POSNA symposium is important and make some recommendations on directions where we as individuals and as a professional society should be putting in our efforts and resources.

Diffusion-weighted MRI for outcome prediction in early Legg-Calvé-Perthes disease: Medium-term radiographic correlations

BACKGROUND

Outcome prediction at the early sclerotic stage of Legg-Calvé-Perthes disease (LCPD) is valuable to select patients likely to benefit from early surgery. The metaphyseal apparent diffusion coefficient (ADC) ratio correlated significantly with Herring's classification of LCPD in a preliminary study of 49 MRIs, in which values greater than 1.63 were associated with poor outcomes. The objective of this study was to determine whether the femoral neck ADC ratio, with the 1.63 cut-off, determined at the initial stage of LCPD correlated with medium-term radiographic outcomes.

HYPOTHESIS

The metaphyseal ADC ratio correlates significantly with medium-term radiographic outcomes of LCPD.

MATERIALS AND METHODS

A prospective study was performed in 27 children (mean age, 13 years; range, 9.5-16 years) who underwent 49 MRIs at the sclerosis or fragmentation stage of unilateral LCPD. ADCs measured bilaterally at the femoral head and neck were used to compute the corresponding ADC ratios between the affected and unaffected sides. The patients received regular follow-up for at least 5 years. The correlation between the ADC ratios and Stulberg grade at last follow-up was assessed.

RESULTS

After a mean follow-up of 6.8 years (range, 5.2-8.4 years) from the date of the first MRI, 13 hips were Stulberg 1 or 2, 13 were Stulberg 3 or 4, and 1 was Stulberg 5. The metaphyseal ADC ratio increased significantly with the Stulberg grade (p<0.01). When only MRIs obtained at the early stage of sclerosis were considered, the correlation remained significant (p=0.03). It was also significant in the subgroup of surgically treated patients (p<0.0001) but was not significant in the subgroup without surgery (p=0.51). A metaphyseal ADC ratio greater than 1.63 was associated with a worse Stulberg grade (p=0.02).

DISCUSSION/CONCLUSION

Diffusion-weighted MRI is a non-irradiating and non-invasive investigation that contributes to the management of LCPD when used in combination with morphological MRI sequences. Elevation of the femoral neck ADC is a finding of adverse prognostic significance that correlates with Herring's grade at the fragmentation stage and with Stulberg's grade at the healed stage. Early ADC elevation in the affected femoral neck can serve to select those patients most likely to benefit from early surgery before the fragmentation stage, i.e., before Herring's classification can be applied.

LEVEL OF EVIDENCE

III, prospective uncontrolled study 3.