Late modelling changes in Legg-Calvé-Perthes disease (LCPD) with continuing growth to maturity.

The changes occurring with hip bone growth in the typical case of LCPD consist of (1) lack of additional growth in height of the affected femoral capital epiphysis; (2) further increase in femoral capital epiphyseal width over that present at treatment termination, i.e., 4 mm to 7.2 mm; (3) diminution in length of the femoral neck of 11.5 mm over that of the unaffected hip; (4) an almost universal alteration of the plane of the proximal femoral growth plate from linearity to convexity and scattered instances of partial growth plate slowing affecting either the medial or lateral sectors; (5) change of neck-shaft angle from 132 degrees on the unaffected side to 128 degrees on the involved side; there were almost equal instances of partial depression either of the medial or lateral growth plate margins; when the growth of the medial portion was slowed or suppressed, the neck-shaft angle lessened and when the lateral side slowed, the neck-shaft angle increased; (6) diminution in the articular-trochanteric (A-T) difference on the affected side, i.e., 9.5 mm in comparison with 16.8 mm on the intact side; 2 major factors in this lessening of the A-T distance (or conversely, increase in trochanteric height) were slowing of growth of femoral neck while that of the greater trochanter continued normally and diminution in the neck-shaft angle; (7) alteration in the final result rating in Catterall IV group--one poor to fair: Catterall III group--one poor to fair and 2 fair to poor: Catterall II group--no change from good.