P Mertl, P Manopoulos, E Havet, J Lardanchet (Amiens)
Despite improvements in concept and design of modern total knee arthroplasties, these still have finite lifespans. Revision surgery is often the result. Fixation of revision prostheses must ensure maximal survivorship. This study is a retrospective analysis of medium and long term results on 46 TC3 Sigma revision total knee arthroplasties. We submit our results and conclusions concerning centromedullary stem fixation resulting from intra operative stem press-fit.
Clinical evaluation of results has been based on the Knee Society Score. Radiographic evaluation was performed using the Imagika© program. Analysis took place at 2 year follow up and at maximum follow up (mean 7.5 years). The mean clinical score preop was 42 points (range 0-74) and improved to 84.7 (range 50-100) at 2 years, and 83.7 (range 35-100) at final follow up.30 Knees had an excellent result, 7 good, 1 medium, and 8 a poor result at final follow up.The mean score for function improved from 34.3 points (range 0-80) preop to 69.1 (range 20-100) at 2 years, and 64.2 (range 15-100) at final follow up. This series includes 2 failures, one for anteroposterior instability, and the other for aseptic loosening. Radiographic alignment was within normal limits in every case. Press-fit, assessed on the intramedullary cortical border on x-ray, was achieved in 63% of femoral stems and 76% of tibial stems. 57% of knees showed sclerotic lines along the stems. And only 1 case of stem subsidence was seen, this despite evidence of lysis in 23% of cases.
In conclusion, the TC3 revision knee system, in association with press-fit use of intramedullary stems, used in both septic and aseptic revisions results in a satisfactory clinical and radiological outcome, and has a good medium to long term survivorship.