OBJECTIVETo investigate the methods of restoring normal level of rotation center of the hip and limb length in patients with osteoarthritis (OA) secondary to developmental dysplasia of the hip (DDH) using total hip arthroplasty (THA).

METHODSFrom January 2000 to January 2003, total hip arthroplasties were performed for 21 patients (26 hips) with OA secondary to DDH. There were 19 females and 2 males with an average age of 51 years (range from 40 to 66 years). Based on radiographic classification of Crowe, there were 12 in type I, 5 in type II, 2 in type III and IV respectively. In addition to the standard procedure of THA, the methods of restoring normal level of rotating center of the hip included structural bone autografting and medialization of the cup. The methods of limb length restoration included carefully preoperative planning and intraoperative soft tissue release. During the follow-up period at 3, 6, 12 months postoperatively and then annually thereafter, rotation center of the hip and limb length were assessed radiographically. Harris score system (HSS) was used for clinical evaluation.

RESULTSAll the patients were followed up for a mean time of 26.4 months (range from 12 to 48 months). All the patients had restoration of the normal level of rotation center of the hip. At the latest follow-up, Harris score was improved from preoperative 35 points (range from 12 to 68 points) to postoperative 94 points (range from 74 to 100 points).

CONCLUSIONIn addition to standard procedure, the restoration of normal level of rotation center of the hip could be achieved by structural bone autografting and medialization of the cup in THA for patients with DDH. Careful preoperative planning and intraoperative soft tissue release could restore limb length.