Pelvic osteotomies for acetabular dysplasia: development and current concepts in Japan.

Acetabular dysplasia is a leading cause of secondary hip osteoarthritis in Japan and has long been a major indication for joint-preserving surgery. Over the past decades, several unique pelvic osteotomy techniques have been developed in Japan. Representative procedures include Transposition Osteotomy of the Acetabulum, Rotational Acetabular Osteotomy, Eccentric Rotational Acetabular Osteotomy, Curved Periacetabular Osteotomy, and Spherical Periacetabular Osteotomy. Although these procedures share the common objective of improving femoral head coverage and preserving the native hip joint, each procedure has evolved independently with distinct surgical concepts, osteotomy designs, and technical characteristics. Numerous studies have demonstrated favourable clinical outcomes after these procedures when appropriate patient selection is performed. Recent advances in three-dimensional imaging, computer simulations, and computer-assisted surgery have further refined surgical planning and postoperative assessments. This review summarises the historical evolution, surgical concepts, indications, clinical outcomes, and future perspectives of pelvic osteotomies developed in Japan, highlighting their individual characteristics and continuing roles in contemporary joint-preserving hip surgeries.