The effect of viscosupplementation on neuromuscular control of the knee in patients with osteoarthritis.

Objective: The aim of this study was to investigate the short-term effects of intra-articular injection of hyaluronan (Hylan G-F 20) on proprioception, isokinetic muscle force, self reported pain, and functional condition in patients with knee osteoarthritis (OA).

Methods: 63 patients with stage II-III bilateral knee OA were included in this randomized, placebo controlled, and prospective study. Subjects were randomized with 42 of them into the treatment group and 21 of them into the placebo group. Hyaluronan was intraarticularly injected into both knees of the subjects which were in the treatment group, whereas physiological saline was intraarticularly injected to the subjects which were in the placebo group. Proprioception and the isokinetic muscle force measurement were performed. Visual analogue scale (VAS) and WOMAC scale were used to evaluate pain and physical function.

Results: Statistical analysis was performed on 120 knees of 60 patients completing the trial. The average absolute angular error (AAAE) value showing the proprioceptive error level in the treatment group was detected to be statistically significantly lower compared to placebo at the measurements performed after the 3rd injection (p = 0.02) and after one week (p = 0.01). While there was no inter-group difference in isokinetic measurements performed at 180 and 240 degrees/sec, a significant difference was detected at the measurement performed at 60 degrees/sec in favor of the treatment group (p = 0.02). Activity and resting VAS-pain values, WOMAC parameters (except the WOMAC stiffness) were detected to be significantly lower in the treatment group. Local adverse events were not reported in any patient.

Conclusion: In this study, it was demonstrated that intraarticular injection of hyaluronan in patients with knee OA led to a short-term increase in proprioception and isokinetic muscle force, and also significant improvements in the functional conditions of patients. Long-term studies are needed.