Comparison of a new mobile-bearing total knee prosthesis with a fixed-bearing prosthesis: a matched pair analysis

Background

New prosthesis designs should provide either superior function or durability. Before long time follow up studies are started it should at least prove its effectiveness in clinical outcomes. Therefore we have studied the early clinical results of a new mobile bearing total knee prosthesis (e.motion; Aesculap^®) in comparison with our established fixed-bearing device (PFC; DePuy^®) in a matched-pair analysis.

Patients and methods

About 30 consecutive patients received the new mobile bearing device and were matched with patients who received the PFC prosthesis according to age, gender, weight, axis and preoperative AKS-score. Outcomes were measured using the scores that are routinely documented in our arthroplasty register namely the American Knee Society Score (AKSS), the Oxford Knee Score (OKS), Functional Questionnaire of Hannover for Osteoarthritis (FFbH-OA), range of motion (ROM) and knee pain before and 2 years after the operation.

Results

No statistical differences could be found neither preoperative nor postoperative. Nevertheless the mobile bearing device had a slightly better ROM and function score.

Conclusion

This new device proved to be at least as effective in early clinical outcome as the established fixed bearing prosthesis. It has to be awaited whether it is advantageous in the long run.