Outcome of isolated polyethylene tibial insert exchange after primary cemented total knee arthroplasty

Total knee arthroplasty using a modular design gives the possibility for an isolated exchange of the tibial polyethylene insert in patients with failed total knee arthroplasty. The success of this kind of surgery is still controversial. We analysed the clinical outcome after isolated tibial polyethylene insert exchange.

In this retrospective study we included 62 consecutive patients with an isolated tibial polyethylene insert exchange at our institution. The average follow-up was 35 months. For clinical evaluation we used the Oxford Knee score, the Knee Society score, the Turba score, and the Kujala score. The health-related quality of life was determined with the SF-36 score and the visual analogue pain scale.

The operations were performed 73 months after primary total knee arthroplasty on average. The main reasons for isolated tibial polyethylene insert exchange were instability and wear. In the clinical outcome patients achieved 31.5 points in the Oxford Knee score, 120.5 points in the Knee Society score, 9.3 points in the Turba score, and 49.0 points in the Kujala score. Mean level of persisting pain was 2.2. In the SF-36 score patients achieved 36.3 points physical and 51.7 points mental. The overall survival for isolated tibial insert exchange revealed 72.2 % survival at 6.25 years follow-up with a repeat revision rate of 11 %.

Isolated tibial polyethylene insert exchange revealed a good clinical outcome. There is a tendency for better results in comparison with the information given in literature for most of the parameters including a lower rate in repeat revision.