Early Failure of Total Hip Arthroplasty with Hydroxyapatite-Coated Smooth Surface Acetabular Component

Abstract

Purpose : To evaluate the early intermediate outcomes of total hip arthroplasty using hydroxyapatite (HA)-coated smooth surface hemispherical acetabular component. Materials and Methods : Seventy total hip arthroplasties were performed, in 63 patients, using a HA-coated smooth surface hemispherical acetabular component consecutively between June 1993 and August 1996. Fifty-four cases were followed at an average of 71 months. The mean age at the time of arthroplasty was 49 years old. Clinical results were evaluated using the modified Harris hip score, and the radiologic results were evaluated in terms of stability, polyethylene wear rate, and osteolysis around the acetabular component. Results : The mean preoperative Harris hip score of 50.9 was improved to 82.2 points at the most recent follow-up. Pelvic osteolysis was found at 18 cases (33%) and the mean polyethylene wear rate was 0.15 mm/year. Eight acetabular components (15%) were unstable radiologically and 7 acetabular components (13%) were revised. Conclusion : Total hip arthroplasty using HA-coated smooth surface hemispherical acetabular component showed accelerated polyethylene wear rate, which was accompanied by a high incidence of osteolysis, and a high loosening rate due to failure of bony ongrowth at early midterm.