Percentages represent frequency of chondral damage found in each of the eight sectors in study by Albers et al. (From Albers CE, Steppacher SD, Ganz R, et al: Joint-preserving surgery improves pain, range of motion, and abductor strength after Legg-Calvé-Perthes disease, Clin Orthop Relat Res 470:2450–2461, 2012.) SEE TECHNIQUE 32.6.