THR with Hydroxyapatite - coated Hip Prosthesis

Kim, Ki Soo; Chung, Young Yool; Han, Seung Chae; Yoon, Sun Yong; Shon, Kwang Soo

Abstract

Synthetic hydroxyapatite is a safe, nontoxic, biocompatible, and osteoconductive material. Hydroxyapatite-coated implants have the property of achieving a very strong bond with living bone in a relatively short period. From March 1992 to June 1994, 140 hydroxyapatite-coated primary total hip prostheses were implanted. This study included 60 cases that could follow up minimum 3 years. At the time of mean follow up, 45 months after operation, the mean Harris hip score was 92 points. Only two patients complained of thigh pain at last follow up. On radiographic evaluation, radiolucent lines were seen around the uncoated distal part of the stem in 46 percents of the implants. No radiolucent line was observed around the coated area of the prosthesis. Cancellous condensation was seen in 95 per cents of the implants at the Gruen zone 2 and 6 area. Cortical hypertrophy was present in 32 percents. Fourteen cases had the gaps at the bone to acetabular cup interface in the immediate postoperative period. The gaps disappeared in 12 months after operation. Five implants were revised because of polyethylene wear, cup migration and periprosthetic fracture. The clinical outcome was excellent. But this result was obtained in the relatively short-term follow up. Longer-term data will be the only true test of the value of hydroxyapatite coated implant.