Cementless femoral components should be made from cobalt chrome.

Before 1982, the authors performed 177 primary total hip arthroplasties using a single-sized, extensively porous-coated cobalt-chrome femoral prosthesis. The current status of 122 of these arthroplasties is known. Two femoral prostheses have been revised for late symptomatic loosening, 2 for stem fracture, and 1 for infection. From 1982 to 1984, 227 primary arthroplasties were performed using the same stem in multiple sizes. Of these cases, 171 are available for followup. One stem (0.6%) has been revised for symptomatic loosening. Large osteolytic femoral lesions (average size, 8.1 cm2) developed in 3 patients, associated with an unusually large amount of polyethylene wear of their acetabular components. These patients have been treated by exchange of the polyethylene liner within the porous-coated acetabular component and allografting of the osteolytic lesions. The femoral components were not exchanged because osteolysis had not eroded the integrity of the supporting bone-implant interface to a point where loosening occurred. Before 1987, 193 patients with loose femoral components were treated with revision total hip arthroplasty, also using an extensively porous-coated cobalt-chrome femoral stem of similar design. Ten (5.7%) patients have required rerevision of the femoral prosthesis. Six of these 10 rerevisions were performed because of symptomatic loosening. Ninety-three percent of the patients in the primary series had relief of their preoperative pain and have improved functional ability; 94.2% are satisfied with their results. In the revision series, 89.1% of the patients are free of pain and function better than preoperatively, and 89.6% are fully satisfied with their results.(ABSTRACT TRUNCATED AT 250 WORDS)