[Changes in muscle torque in patients after total knee arthroplasty]

Abstract

Aim: The purpose of this study was to compare muscle torque during isokinetic knee movements of patients after total knee arthroplasty (TKA) with a similar healthy group.

Method: 43 patients were examined 3 years after primary total knee arthroplasty with an isokinetic dynamometer (Cybex 340). Torque measurements were evaluated for extension and flexion with 4 different velocities. The results were compared with a group of 43 people without knee disease. Bouth groups consist of 29 women and 14 men. The mean age was also comparable (66.4 vs. 65.8 years).

Results: A mean peak torque of 65.9 Nm was measured during extension with low velocity (60 degrees /s) in the group of patients with TKA -- 84.3 % of the control group (p = 0.079). At the highest velocity the patients produced 30.2 Nm. This was 72.8 % of the control group (difference statistically significant, p = 0.006). No differences were found in the Extension/Flexion ratio between the two groups.

Conclusion: The deficites of knee strength in patients after TKA are more distinct in high velocities of motion.