The porous-coated anatomic (PCA) total hip was a first-generation cementless implant system introduced in 1983 for both primary and revision total hip arthroplasty. Between February 1983 and June 1989, 219 uncemented PCA total hips were implanted in 194 patients as part of a multisurgeon, single-institution, prospective study. Short-term follow-up data were available on 212 hips at an average of 21.7 months. At the time of final follow-up, data were available on 121 hips at an average of 20.2 years (range, 18-24 years). Of the surviving patients, 55% had undergone revision. Of those patients with known failure mechanisms, 66% underwent revision for isolated acetabular osteolysis or loosening, 23% for femoral component failure, and 11% for failure of both components. As has been reported in other series, the acetabular component appeared to be the most common cause for revision, while the femoral component proved more durable.