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Reliability and stability of three common classifications for Legg-Calvé-Perthes disease
Moon Seok Park1, Chin Youb Chung, Kyoung Min Lee
1Department of Orthopaedic Surgery, Seoul National University Bundang Hospital, 300 Gumi-Dong, Bundang-Gu, Sungnam, Kyungki 463-707, Korea.
Insights
The Herring lateral pillar classification is most reliable for Legg-Calvé-Perthes disease (LCPD). However, initial Herring Group A classifications may be upgraded, suggesting surgical consideration for older patients.
Area of Science:
- Orthopaedic Surgery
- Pediatric Orthopaedics
- Radiographic Assessment
Background:
- Accurate prediction of Legg-Calvé-Perthes disease (LCPD) progression is crucial for early treatment decisions.
- Reliable classification systems are needed to guide clinical management and predict outcomes.
Purpose of the Study:
- To evaluate the reliability and stability of three common LCPD classification systems: Herring lateral pillar, Catterall, and Salter-Thompson.
- To determine which classification system offers the most consistent and dependable assessment of LCPD.
Main Methods:
- Retrospective review of hip radiographs from 69 LCPD patients with serial imaging.
- Assessment of inter- and intrarater reliability using intraclass correlation coefficients (ICCs).
- Evaluation of classification stability through initial, fragmentation, and final ratings.
Main Results:
- Herring lateral pillar classification demonstrated the highest interrater reliability (ICC, 0.885).
- Catterall (ICC, 0.802) and Salter-Thompson (ICC, 0.702) showed lower interrater reliability.
- Significant changes (upgrades) were observed in over 40% of initial classifications, particularly Herring Group A.
Conclusions:
- The Herring lateral pillar classification is the most reliable among the evaluated systems for LCPD.
- Clinical vigilance is required as initial Herring Group A classifications may be upgraded, especially in patients over 8 years old.
- Consideration of surgical intervention is advised for Herring Group A patients over 8 years old due to potential disease progression.
Background:
To predict the course of Legg-Calvé-Perthes disease (LCPD) and select between treatment options in the early stages, it is critical to have a reliable predictive classification.
Questions/Purposes:
We examined the reliability and stability of three common classification systems for LCPD.
Methods:
We identified 69 patients with LCPD, who had hip radiographs taken more than twice after the initial presentation with at least a 3-month interval. The Herring lateral pillar, Catterall, and Salter-Thompson classifications were evaluated in terms of reliability and stability. The inter- and intrarater reliability of the classification systems was determined by three orthopaedic surgeons using intraclass correlation coefficients (ICCs). To evaluate the stability of the classification systems, the percentage agreement and ICCs among the initial rating, rating when entering fragmentation, and final rating were used.
Results:
The interrater reliability was highest in Herring lateral pillar classification (ICC, 0.885) followed by the Catterall and Salter-Thompson classifications (ICC, 0.802 and 0.702, respectively). The percentage agreement and ICC between the initial and final rating were, respectively, 55% and 0.491 for the Herring classification and 48% and 0.378 for the Catterall classification.
Conclusions:
Our data show the highest reliability of the classification of Herring et al. However, more than 40% of the hip radiographs at the initial presentation, and in particular, most of Herring Group A patients, were upgraded. Therefore, for patients older than 8 years old and graded as Herring Group A initially, surgeons should keep the possibility of surgical treatment in mind.
