Hip range-of-motion (ROM) is less than normal after rotational acetabular osteotomy for developmental dysplasia of the hip: A simulated ROM analysis

The optimal reorientation of the acetabulum for developmental dysplasia of the hip (DDH) is unknown in terms of hip range-of-motion (ROM). The simulated ROMs of 52 DDHs after rotational acetabular osteotomy (RAO) with several patterns of femoral head coverage and those of 73 normal hips were analyzed using computer models reconstructed from CT images. After RAO with a lateral center edge angle (LCEA) of 30 degrees and an anterior center edge angle (ACEA) of 55 degrees producing coverage similar to that of normal hips, the maximal flexion and maximal internal rotation at 110 degrees flexion with 20 degrees adduction were significantly smaller than those of the normal group. To achieve ROMs after RAO similar to those of the normal group, an LCEA of 30 degrees with an ACEA of 45 degrees, an LCEA of 25 degrees with an ACEA of 45 degrees to 50 degrees, and an LCEA of 20 degrees with an ACEA of 50 degrees could be preferred angles to target, even though they provided smaller coverage than that of normal hips. After RAO producing femoral head coverage similar to that of normal hips, the maximal flexion and the maximal internal rotation at 110 degrees flexion with 20 degrees adduction were significantly smaller than those of the normal group. (c) 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:217-223, 2016.