Impact of knee arthroplasty on knee sensorimotor system performance.

BACKGROUND The study aimed to assess the impact of joint degeneration due to advanced gonarthrosis and the effect of arthroplasty on proprioception and sensorimotor system performance of the knee. MATERIAL AND METHOD The arthroplasty group comprised 62 persons, aged 68.8 years on average, who underwent knee replacement due to gonarthrosis. The control group consisted of 74 healthy persons, with an average age of 67.5 years. The participants performed a test of Joint Position Sense (JPS) at 45° flexion and a Sensorimotor Control Test (SCT) designed by the authors to evaluate sensorimotor system performance (on a scale of 0-5). The arthroplasty group was assessed three times: before the knee replacement surgery, and then at 8 and 100 days after the surgery. The control group was assessed once. RESULTS The control group scored a mean of 4.9 in the SCT test and 3.9° in the JPS test. The mean scores upon consecutive measurements in the arthroplasty group were 3.1, 2.9 and 4.5 for the SCT test and 10.5°, 9.5° and 3.9° (compared to 8.1° for the healthy limb) for the JPS test. CONCLUSIONS 1. Considerable proprioceptive and sensorimotor system performance deficits, as recorded in the arthroplasty group, may contribute to faster progression of degenerative disease and increase the risk of a fall. 2. The Sensorimotor Control Test designed by the authors seems to represent an objective and comprehensive method for assessing the sensorimotor system performance of the knee in gonarthrosis patients. 3. The Sensorimotor Control Test provides a qualitative assessment and may be employed in the clinical therapeutic setting.