Total hip arthroplasty with the porous-coated anatomic (PCA) prosthesis: the acetabular component.

Two hundred and twenty-eight uncemented total hip arthroplasties using the porous coated anatomic (PCA) one-piece acetabular component were implanted between June 1984 and July 1987 at two hospitals. The PCA total hip was one of the first hip implants to offer uncemented fixation by bone ingrowth. It was used in the younger patients with adequate bone stock. While most arthroplasties were performed for osteoarthritis, it was also used in rheumatoid arthritis, osteonecrosis and dysplastic hips. Revisions were excluded in this series. Bone grafts (autograft) were used to reconstruct the acetabulum in segmental and contained defects. All components were inserted without cement. In all cases a 32 mm femoral head was used. In cases of protrusion often the deep socket design was inserted for reestablishment of the anatomic hip rotation center. Initial cup stability was aimed for by line to line reaming while rotatory stability was augmented by the presence of two peripheral pegs. A maximum contact with the acetabular rim was always aimed for. A variation of the straight lateral approach was used in all cases. In a prospective study the clinical scores were evaluated. X rays were evaluated on AP and lateral views taken immediately after the operation, at two years and at latest follow-up. Cup migration was recorded when there was a change in cup angle, vertical migration of more than two millimeters. Polyethylene (PE) wear was recorded in case of eccentric localisation of the femoral head in the cup. The relationship between PE wear and cup size was also recorded.(ABSTRACT TRUNCATED AT 250 WORDS)