Mobile versus fixed-bearing total knee arthroplasty: mid-term comparative clinical results of 216 prostheses.

Since the late 1970s, mobile-bearing total knee designs have been advocated as having theoretical advantages over fixed-bearing total knee replacements. At present there is no consensus as to whether there are any differences in clinical results between the two designs. We present the results of two consecutive cohorts each of over 100 prosthesis. The first cohort underwent a fixed-bearing prosthesis, whilst the second cohort received the mobile bearing variant of the same prosthesis. Both groups were assessed pre- and post-operatively using the American Knee Society knee and function scores as well as range of movement and the presence or absence of anterior knee pain. No difference was found statistically significant between the groups, either for the knee score (P=0.068), the function score (P=0.26), the range of movement (P=0.11) or the proportions of anterior knee pain (P=0.06). It is our opinion that mobile bearing knee prosthesis have still to prove their theoretical advantages in clinical practice.