Surgical correction of "functional retroversion" and "functional coxa vara" in late Legg-Calvé-Perthes disease and epiphyseal dysplasia: correction of deformity defined by new imaging modalities.

We studied six patients with severe femoral head deformity treated surgically by valgus-flexion-internal-rotation femoral osteotomy plus simultaneous acetabuloplasty based on the concept of "functional retroversion" and "functional coxa vara" of the deformed femoral head in late severe Legg-Calvé-Perthes disease and epiphyseal dysplasia. The combined procedure achieves the following: (i) corrects the "functional coxa vara" and hinge abduction (valgus osteotomy); (ii) establishes a more normal articulation between the posteromedial portion of the true femoral head and the acetabulum, while moving the anterolateral protruding portion of the femoral head away from the anterolateral acetabular margin (valgus-flexion osteotomy); (iii) corrects external-rotation deformity of the distal limb (internal-rotation osteotomy); (iv) improves joint congruity and anterolateral femoral-head coverage in hips with associated acetabular dysplasia (acetabuloplasty).