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Multicenter study for Legg-Calvé-Perthes disease in Japan
Wook-Cheol Kim1, Kazuo Hiroshima, Toshihiko Imaeda
1Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyou-ku, Kyoto 602-8566, Japan.
Insights
This study collected epidemiological data on Legg-Calvé-Perthes disease (LCPD) in Japan, finding that operative treatment showed a better outcome than conservative methods. The optimal treatment for LCPD remains undetermined, but outcomes are comparable to global reports.
Area of Science:
- Orthopedics
- Epidemiology
- Pediatric Health
Background:
- A multicenter study was initiated by the Japanese Pediatric Orthopaedic Association in 2000 to investigate pediatric orthopedic diseases.
- The primary objective was to gather epidemiological data on Legg-Calvé-Perthes disease (LCPD) within Japan.
Purpose of the Study:
- To collect and analyze epidemiological data for Legg-Calvé-Perthes disease (LCPD) in Japan.
- To identify predictors of outcome and compare treatment methods for LCPD.
Main Methods:
- A survey collected data on patient demographics, diagnosis, family and sports history, affected sites, symptoms, pain location, and classifications (Catterall, Herring, Stulberg).
- Treatment methods, bracing periods, and outcomes were recorded for 711 patients (766 hips) diagnosed between 1993 and 1995.
- Ordinal logistic regression analysis was used to determine significant predictors of outcome.
Main Results:
- The average annual incidence of LCPD was 0.9/100,000, with the average age at diagnosis being 7 years and 1 month.
- The male to female ratio was 6.3:1.0, and 7.7% of patients had both hips affected.
- Operative treatment demonstrated a better outcome (odds ratio 1.872) compared to conservative treatment, with Herring classification and age at diagnosis being significant predictors.
Conclusions:
- While numerous containment methods for LCPD are used in Japan, this study did not determine an optimal treatment.
- The overall outcomes for LCPD in Japan were found to be comparable to international reports.
- Herring classification, age at diagnosis, and affected side were significant predictors for LCPD outcomes.
Background:
The Japanese Pediatric Orthopaedic Association created a project team in 2000 to research pediatric orthopedic disease through a multicenter study. The aim of this study was to collect epidemiological data on Legg-Calvé-Perthes disease (LCPD) in Japan.
Methods:
The following data were collected by a survey: age, sex, date of diagnosis, family history, sports history, affected sites, symptoms, location of pain, Catterall classification, Herring classification, date of treatment initiation, treatment methods, bracing period, and Stulberg classification.
Results:
A total of 711 patients with 766 affected hips were seen from January 1, 1993 to December 31, 1995. The average annual incidence of LCPD was 0.9/100 000. The average age at diagnosis was 7 years 1 month (2.3-14.3 years). The male/female ratio of the study population was 6.3 : 1.0. The affected-side ratio (right hip/left hip/both hips) was 5.1 : 6.8 : 1.0. Both hips were affected in 7.7% of this series. By the Stulberg classification there were 211 (69.4%) type I and II patients (of 304 total patients). Six treatment methods for unilateral LCPD were compared, and there were no significant differences in outcome among the six groups. The ordinal logistic regression analysis showed that the Herring classification, age at the time of diagnosis, and the affected side (for unilateral LCPD) were significant predictors. The ordinal logistic regression analysis also showed that operative treatment had a better outcome than conservative treatment, with an odds ratio of 1.872.
Conclusions:
Many containment methods for LCPD have been performed in Japan, and the optimal treatment method for LCPD was not determined in this study. The overall outcome, however, was not worse than that in worldwide reports.

