According to the Herring lateral pillar classification for Legg-Calvé-Perthes disease, a patient exhibiting less than 50% maintenance of the lateral pillar height is classified as:
A
Group A
B
Group B
C
Group C
D
Group B/C border
Explanation
Group C in the Herring classification indicates severe involvement with less than 50% maintenance of the lateral pillar height.
Clinical Context: The Herring classification is assessed on an anteroposterior (AP) pelvis radiograph during the fragmentation stage of Perthes disease. The lateral pillar (the lateral 15-30% of the epiphysis) acts as a crucial weight-bearing column.
- Group A: 100% lateral pillar height maintained.
- Group B: >50% lateral pillar height maintained.
- Group C: <50% lateral pillar height maintained.
- Group B/C border: Exactly 50% height, or a narrow lateral pillar.
Prognosis is heavily dependent on age at onset and Herring classification. Children over 8 years old with Group B or B/C hips benefit most from surgical containment (e.g., femoral or pelvic osteotomy). Group C hips universally have poor outcomes, regardless of age or surgical intervention, often leading to aspherical congruency or incongruency.
References:
1. Herring JA, et al. 'The lateral pillar classification of Legg-Calvé-Perthes disease.' J Pediatr Orthop. 1992.
2. Herring JA, et al. 'Legg-Calvé-Perthes disease. Part II: Prospective multicenter study of the effect of treatment on outcome.' J Bone Joint Surg Am. 2004.