IS KNEE-JOINT PROPRIOCEPTION WORSE IN THE ARTHRITIC KNEE VERSUS THE UNAFFECTED KNEE IN UNILATERAL KNEE OSTEOARTHRITIS

Objective. Neuromuscular joint protection requires proprioceptive inpu t and motor output. Impairment of proprioception in knee osteoarthriti s (OA) may contribute to, and/or result from, the disease. If this imp airment was exclusively a local result of OA, a between-knee differenc e would be expected in patients with unilateral OA (UOA). To explore c ausal directions, 2 hypotheses were tested: 1) proprioception is worse in UOA patients versus elderly controls; 2) proprioception is worse i n the arthritic knee versus the unaffected knee in UOA patients. Metho ds. Twenty-eight UOA patients (Kellgren-Lawrence grade greater than or equal to 2 in 1 knee and <2 in the other knee) and 29 elderly control s were enrolled. The unaffected knee of each UOA patient and both knee s of the elderly controls were required to meet symptom, examination, and radiographic criteria. Proprioception (detection threshold of join t displacement after slow, passive, automated knee motion), body mass index, pain, functional status, range of motion, and laxity were measu red. Results. UOA patients had worse proprioception than did elderly c ontrols, in either knee, A between-knee difference was not found in UO A patients. Conclusion. Impaired proprioception is not exclusively a l ocal result of disease in knee OA. The relative importance of impaired proprioception in the development and progression of knee OA will req uire longitudinal study.