To test the hypothesis that treatment of the osteoarthritic knee with intraarticular hyaluronan may improve proprioception.
Forty-six patients with unilateral osteoarthritis of the knee were recruited for this study from primary care clinics in the Department of Family Medicine at the University of Western Ontario. Inclusion required (1) the presence of pain with activities of daily function and (2) radiographic confirmation of medial compartment osteoarthritis. Proprioception was measured with an electrogoniometer attached to the study knee. Subjects performed an angle reproduction test in the closed kinetic position. The difference between the target test angle and the reproduced angle was labeled the absolute angular error (AAE). Eleven angles were tested in random order before beginning therapy, after 3 weeks, and after 12 weeks.
Twenty-one men and 19 women completed the study (22 subjects received hyaluronan injections and 18 subjects received a placebo injection). No significant differences existed between the study groups in age, the timing of injections, or proprioceptive testing. A 2 x 3 repeated measures analysis of variance (ANOVA) comparing injection groups at all times revealed no significant differences in AAE. The AAE proprioception data was examined for differences due to fatigue caused by the number of test angles (p < .001) and differences explained by angulations in various divisions of the normal range of motion (p < .001). After accounting for these potential confounds, a two-way ANOVA still did not detect any significant differences in AAE between hyaluronan and placebo groups.
Other studies have found that proprioception may be impaired in osteoarthritic knees and that viscosupplementation therapy with hyaluronan may decrease pain and increase function in these knee joints. The results of the present study suggest that this therapy does not adversely affect proprioception and that a longer, longitudinal study is required to determine if viscosupplementation treatments could attentuate proprioceptive decline.