The Rotaglide+ total knee replacement: a comparison of mobile versus fixed bearings.

PURPOSE: Mobile-bearing knee replacements were introduced as an alternative to their fixed-bearing counterparts. Movement of the polyethylene insert relative to the tibial tray has been shown to decrease contact stresses, wear and polyethylene-induced osteolysis. The aim of this study is to compare outcomes between mobile and fixed-bearing surfaces of the Rotaglide+ total knee prosthesis.

METHODS

A prospective, partially randomised twin cohort study of 149 Rotaglide+ total knee arthroplasties performed in one unit between September 2000 and January 2005, was carried out. The patients were allocated to a mobile or fixed bearing. The patients were assessed using a pain visual analogue score (VAS), the American Knee Surgeons Score (AKSS) the range of movement, the Oxford Knee Score (OKS) and walking time. Seventy-five patients had mobile-bearing surfaces, and 74 had fixed bearings.

RESULTS

At 5-year follow-up, there was no significant difference between the fixed- and mobile-bearing implants with respect to range of movement [104.7(SD 17.0) vs. 103.6(SD 15.7) degrees]; AKSS [146.6(SD 23.9) vs. 144.1(SD 32.4)]; VAS [3.3(SD 1.2) vs. 3.4(SD 1.3)]; OKS [30.8(SD 9.7) vs. 29.6(SD 10.9)], respectively.

CONCLUSION

This study is the first of its kind to outline the medium-term (≥5 years) outcomes in Rotaglide+ total knee replacements. Its findings reinforce previous research which has shown no discernible difference in clinical outcomes between the 2 groups.