Survivorship at minimum 10-year follow-up of a rotating-platform, mobile-bearing, posterior-stabilised total knee arthroplasty.

PURPOSE: To evaluate prospectively the long-term clinical and radiographic results and survivorship of a rotating-platform, posterior-stabilised knee prosthesis at minimum 10 years (mean 11.5 ± 1.41 years), and to test the hypothesis that this design would have a mechanical survivorship greater than 95%.

METHODS

Between 2000 and 2002, 160 consecutive patients (166 knees) underwent total knee arthroplasty using a rotating-platform, posterior-stabilised prosthesis, and clinical and radiographic follow-up data were gathered prospectively.

RESULTS

One hundred and seven patients (112 knees) were available for final follow-up. Five patients (3%) had undergone revision surgery, giving a Kaplan-Meier survival rate of 96.6% for all causes of failure. No spin-out of the polyethylene insert was observed. The mean visual analogue scale, Knee Society and Oxford Knee Scores showed statistically significant improvements (p < 0.001). On radiographs, two cases (2.4%) had radiolucent lines >2 mm, and no patient had osteolysis.

CONCLUSIONS

The absence of osteolysis at minimum 10 years seems to support our hypothesis that this design may be able to reduce peri-prosthetic bone resorption in the long term. The survivorship was greater than 95% and is comparable to the best results reported for this type of knee prosthesis in the literature. The clinical scores are reasonable, given the presence of various disabling concomitant pathologies and the relatively advanced mean age of the study population. This study is clinically relevant because it adds valuable information to the limited data regarding the long-term survivorship and performance of rotating-platform knee prostheses and, more specifically, of a single knee design.

LEVEL OF EVIDENCE: IV.