Aim: Evaluation of clinical, electromyographic and gait analysis results after constrained revision total knee arthroplasty. Material and Methods: 14 patients (mean age 67 years, 54-78) were evaluated 28.5 months (range, 6.5 to 61.4 months) after revision arthroplasty using constrained total knee endoprostheses (Genesis, Blauth).

Clinical evaluation was carried out using HSS, Knee Society, Tegner Activity, and Patellar scores. A three-dimensional, quantitative gait analysis and simultaneous epicutaneous electromyographic recordings of 7 muscles surrounding the knee were carried out on all patients. 11 healthy volunteers (mean age 69 years, 60-75) served as control group.

Results: Patients achieved 68 points in HSS, 125 in Knee Society, 1.3 in Tegner, and 19.1 in Patellar scores. Compared to the controls, all patients showed minor functional results. Electromyographic amplitudes of 5 muscles of the operated leg were significantly decreased compared to the contralateral side as well as the control group. Besides maximum knee extension all gait analysis parameters differed significantly between patients and controls. On the other hand, operated and uninvolved patients’ legs differed only in maximum knee extension in gait analysis. Significant correlations between clinical scores and ground reaction forces as well as electromyo-graphic levels of the gastroc muscle were noticed.

Conclusion: Functional deficits may not be explained by revision arthroplasty alone, but already exist preoperatively. The gastroc muscle seems to play and especially important role, as its functional deviations are highly correlated with clinical scores. The shown results stress the demand for extensive pre- and postoperative rehabilitation to avoid or at least reduce functional deficits after revision total knee arthroplasty.