Osteolysis caused by wear of the ultrahigh molecular weight polyethylene (UHMWPE) often leads to failure. Cross-linking improves wear, but also produces residual free radicals that decrease oxidative stability. 58 patients (64 observed hips), all with osteoarthritis, gave informed consent to participate in a 5 year RSA study. Each patient received a VEPE liner, a Regenerex™ acetabular shell, and an uncemented stem with either a 32mm or 36 mm cobalt chrome femoral head. Tantalum beads were inserted into the VEPE, the pelvic and the femoral bone to measure head penetration into the polyethylene, and shell and stem stability over time, using RSA. RSA radiographs were scheduled immediately postoperatively (up to 6 weeks) and 6 months, 1, 2, 3, and 5 years after surgery. The Wilcoxon signed-ranks nonparametric test was used to determine if changes in penetration or migration were significant over time at p≤0.05.Introduction
Methods
