Journal of Pediatric Orthopaedics - 2026-06-23 - Journal Article
Lateral Pillar Predicts Success of Greater Trochanter Apophyseodesis in Legg-Calvé-Perthes Disease.
Campa W, Price M, Tamai J, Mehlman CT
Topics
Key Takeaway
GTA reduces ROGT frequency in Herring B and C LCPD, but LP C patients maintain high residual ROGT rates despite equivalent absolute trochanteric growth inhibition to LP B patients.
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Summary
This study evaluated whether Herring lateral pillar classification predicts GTA success in 139 unilateral LCPD patients followed to skeletal maturity, comparing 73 GTA patients to 66 controls stratified by LP class. ATGI was equivalent across LP B, B/C, and C groups, confirming GTA mechanically inhibits trochanteric growth regardless of disease severity. Despite this, LP C patients had persistently high ROGT rates, with significantly shorter, wider femoral necks and reduced neck-shaft angles compared to LP B patients, indicating that trochanteric overgrowth in severe disease is driven by proximal femoral growth failure rather than trochanteric overgrowth alone.
Key Limitation
ROGT threshold defined as below the 5th percentile of unaffected contralateral hips introduces a reference standard that may not account for bilateral growth effects in severe LCPD, potentially misclassifying some outcomes.
Original Abstract
BACKGROUND
Proximal femur growth requires a dynamic balance between the femoral head, neck, and greater trochanter. Severe Legg-Calvé-Perthes disease (LCPD) disrupts this balance, limiting femoral head and neck growth as the greater trochanter grows normally. This relative overgrowth of the greater trochanter (ROGT) can further impair already compromised hip function. Greater trochanter apophyseodesis (GTA) is a surgical procedure aimed at preventing ROGT and has varying effectiveness depending on disease severity. The purpose of this study was to evaluate the association between disease severity, as determined by the lateral pillar (LP) classification, and ROGT in patients undergoing GTA and to compare outcomes with controls.
METHODS
We retrospectively reviewed 139 patients with unilateral LCPD treated at a single institution between January 1998 and June 2025. Seventy-three patients underwent GTA while 66 served as controls. All patients were followed to skeletal maturity. Patients were stratified by LP classification (B, B/C, C) and age. Radiographic measurements included articulotrochanteric distance (ATD), center-trochanteric distance (CTD), trochanter-to-trochanter distance (TTD), femoral neck length, femoral neck width, and neck-shaft angle to measure proximal femoral morphology. ROGT was defined as an ATD or CTD below the 5th percentile of measurements in unaffected hips. Absolute trochanteric growth inhibition (ATGI) was calculated using TTD measurements to determine the inhibition obtained in each GTA.
RESULTS
The GTA had the same effect independent of LP class when measured by ATGI. GTA reduced ROGT frequency in LP B and LP C patients compared with controls. However, LP C patients maintained high rates of ROGT after undergoing GTA. LP C patients exhibited significantly shorter, wider femoral necks and smaller neck-shaft angles compared with LP B patients.
CONCLUSIONS
GTA effectively reduces ROGT across LP classifications, independent of age at surgery. However, high rates of ROGT persist in LP C patients despite experiencing similar levels of inhibition through GTA compared with LP B and B/C patients, with proximal femoral measurements suggesting that LP C patients may need additional interventions to overcome growth disturbances observed in severe cases of LCPD.
LEVELS OF EVIDENCE
Level III-retrospective comparative study.