[Revision surgery of knee endoprosthesis]

Thirty-one revisions for aseptic or septic loosening of knee arthroplasty have been performed between 1983 and 1995. In 18 cases we had loosening of uni- or bicondylar prosthesis and in 13 cases a tricompartmental revision arthroplasty. With an average of 53 months (1.5 to 13 years) after the last operation 21 patients could be examined. Main reasons for failure of uni- and bicondylar prosthesis were as well a proceeding of the arthritis in other compartments, instability, incorrect alignment and other reasons depending on the surgical technique. We found similar reasons in aseptic loosening of total knee arthroplasties including wrong choice of non-constrained condylar prosthesis. Seven cases of late infection affected semi-constrained prosthesis. Two of the reimplantations in a 2-stage procedure failed. Using the Insall-Score in the follow-up the patients reached 71.9 points in the knee score and 58.9 points in the functional score. Patients with former aseptic loosening reached better results than these with septic loosening. 38% were absolutely painfree, 14% complained about permanent pain. Unlimited walking was found 5 times, none of the examined persons was unable to walk. Main problems in revision surgery concern reconstruction of a good alignment and the management of bone loss.