Abstract
We prospectively reviewed patients who had undergone a Revision Total Knee Replacement (TKR) to a mobile-bearing arthroplasty. We wanted to assess functional outcome and survival, and to determine whether the perceived advantages of a mobile-bearing arthroplasty could be expanded to the revision situation.
We divided the patients into two groups. Group 1 consisted of 40 patients who were revised to a rotating platform, with or without stems and augments, and group 2 consisted of 41 patients revised to a varus-valgus constrained mobile-bearing device that still allowed rotation of the bearing. All were assessed with Knee Society Knee Scores, WOMAC, and New Jersey Knee Scores and standard radiographs by an independent examiner.
Group 1 had an average age of 71 years at revision and a follow-up of 5–9 years. Seventy-six percent had excellent or good results with 89% survival at 9 years. Group 2 had an average age of 71 years at revision and a follow-up of 2–5 years. The patient satisfaction score was 8/10 and the normality score was 6.8/10. There was only one case of instability in both groups in a patient with a patellar fracture.
A mobile-bearing TKR can be used in the revision situation with acceptable clinical results and patient outcome without compromising the stability or survivorship in the short-term. It has proved to be a “patellar-friendly” procedure with reduced re-operation for patellar complications; however longer-term studies are required to determine whether the rates of polyethylene wear are reduced by the use of a more congruent articulation.
Correspondence should be addressed to: Associate Professor N. Susan Stott, Orthopaedic Department, Starship Children’s Hospital, Private Bag 92024, Auckland, New Zealand.
