Treatment of osteoarthritis secondary to developmental dysplasia of the hip by total hip resurfacing arthroplasty.

Abstract

Objective To investigate the clinical effect of total hip resurfacing arthroplasty (THRA) for treatment of osteoarthritis secondary to the developmental dysplasia of the hip (DDH). Methods From March 2005 to June 2006, 26 THRA were performed in 25 patients to treat osteoarthritis secondary to DDH. According to the Hartofilakidis classification, 22 hips were classified as dysplasia; 4 as low dislocation. Clin-ical outcomes were evaluated according to Harris score. Central-edge angle, abduction angle, stem-shaft an-gle, hip center, ratio of offset, cover rate of cup were measured radiologically. Bone mineral density was measured before and after THRA. Results The mean follow-up time of the 25 patients was 3.5 years. Using loosening or revision as the end point, the survival rate was 100%. The mean Harris hip score had improved from (46.1±6.57) points preoperative to (92.1±2.59) points at the final follow-up. Radiological measurement showed that the position of cup restored more anatomically after operation. At the sixth month after operation, the BMD ratio reduction occurred in ROI1-ROI 6, which then increased during 6 to 36 months. The BMD ratios of ROI7, ROIL, ROIM had returned to baseline value at the sixth month postoperatively and surpassed the reference by 36 months. Conclusion The clinical results of THRA for treatment of osteoarthritis sec-ondary to DDH are encouraging. The bone stock of proxiaml femur can be reserved and restored effectively. Key words: Arthroplasty,replacement,hip; Hip dislocation,congenital; Bone density