Proprioceptive function in knees with and without total knee arthroplasty.

The goal of this study was to evaluate the differences in angle reproduction capability after nonconstrained posterior cruciate ligament retaining total knee arthroplasty after a follow-up time of 63.9 months compared with the healthy contralateral leg and a control group. In 28 total knee arthroplasty patients (mean age, 65.7 yr) and 25 control subjects (mean age, 55.7 yr), 16 measurements were made between 0 degrees and 90 degrees in 30 degree steps. The leg was positioned by the examiner and then relaxed; afterward, the subject was asked to reproduce the original position. Each measurement was made with the patient or control being blindfolded and not blindfolded to assess the influence of visual control. We found significant differences in total knee arthroplasty patients in contrast to healthy subjects. Without visual control, the mean deviation of the total knee arthroplasty group starting with a 0 degree angle was 7.7+/-5.9 degrees and 4.6+/-4.7 degrees for the healthy subjects. With visual control, the mean deviation in the patient group was 11+/-7.5 degrees, and in the control group, it was 7.2+/-5.0 degrees. Total knee arthroplasty patients did not show significant differences between the operated on and the contralateral knee. Also, in the total knee arthroplasty group, significant differences could not be found comparing reproduction with and without visual control and comparing both starting positions. In the control group, significant differences could be found comparing visual and nonvisual control in the 60 degree angle. The comparison between the 30 and 60 degree repositioning from both 0 and 90 degree starting positions showed a significant difference in the 60 degree angle. In summary, reduced proprioceptive capabilities are present after knee arthroplasty in both the operated on and the contralateral leg in our study group. Postoperative complaints can perhaps be explained by a loss of proprioceptive capabilities, especially at the 60 degree angle. The operative technique should involve special care of ligaments and muscles to preserve stability and receptors as well. Rehabilitation should pay more attention to the remaining receptors.

[Proprioceptive capacities of the knee joint with and without endoprosthesis]. / Propriozeptive Fähigkeiten des Kniegelenkes mit und ohne Endoprothese.

PURPOSE OF THE STUDY: To compare the proprioceptive abilities of total knee arthroplasty patients and a control group. METHOD: In a knee arthroplasty patient group of 28 and in 25 healthy volunteers the proprioceptive function was examined. To measure the proprioceptive function the motion analysis system with reflecting markers was chosen. In each patient 16 measurements from different starting points in different joint positions with and without visual controlling were performed. RESULTS: The results demonstrated significant differences between the patients and volunteers independent of the starting point, the joint position and the visual controlling. Also the comparison with the 30 and 60 degree position showed significant differences. In the patient group were not shown significant values comparing the starting position, the visual controlling and the comparison with the healthy leg. CLINICAL RELEVANCE: Knee arthroplasty conducts to loss of proprioception in the operated and healthy leg. Visual controlling can not solve these problems. The worst results were achieved in 60 degrees position. The starting position can not influence the results.