Two-year follow-up of the PCA noncemented total hip replacement.

The early results with the PCA total hip replacement have been most gratifying, especially the absence of complications related to the acetabular component. The radiographic evaluation was done critically, and the finding of no progressive acetabular radiolucencies was unexpected. Longer-term evaluation of these interfaces is necessary, but the short-term results have been encouraging. No components have migrated despite the absence of adjunct fixation mechanisms such as screws and flanges. The pressfit achieved with the roughened hemispherical surface has been adequate, and the fixation with the two outrigger pegs appears to have been sufficiently stable to preserve the prosthetic stability and has resulted in successful anchorage of all the components. The results with femoral components are obviously related to technique. In a few early cases when undersized prostheses were used, loosening occurred, and four of these components advanced to detectable loosening. One of these components was revised since this analysis. Attention to detail with maximal filling of the proximal femur apparently led to improved results, with successful anchorage in all subsequent implantations. The application of the dimensional analysis before surgery may indicate those cases in which a tight fitting metaphysis cannot be achieved. In elderly patients who have osteoporotic bone, a substantial mismatch exists between the size of the metaphysis and the diaphysis, and it may be advisable to continue with cement in these cases. By applying the dimensional analysis to preoperative templating, the surgeon may be sufficiently informed to know that a tight fit can be achieved at surgery. No catastrophic failures have occurred. If loosening does occur because of undersizing of the prosthesis, the process appears to be gradual and, although associated with pain, does not result in sudden failure. Despite the prosthesis not being anchored by cement or collar, no sudden subsidence of the components has resulted. Patients' clinical performance has been somewhat slower when compared to cemented series. Performance seems to accelerate once weight bearing occurs, however, and after 2 years no difference exists between this series and a corresponding cemented series. Noncemented total hip arthroplasty appears to offer as good if not better results than cemented total hip arthroplasty, if performed correctly and in the appropriate patient. Successful outcome depends greatly on technique, but when technically adequate implantation has been performed, the results have been gratifying.(ABSTRACT TRUNCATED AT 400 WORDS)