Effects of repetitive injections of hyaluronic acid on peritendinous adhesions after flexor tendon repair: a preliminary randomized, placebo-controlled clinical trial.

Background: The aim of this study was to investigate the efficacy of three injections of hyaluronic acid (HA) versus placebo (saline) over a two-week period on functional outcomes after zone-II flexor tendon repairs.

Methods: Twenty-two patients with isolated zone-II flexor tendon injury of the index fingers were included in this study. Before tenorrhaphy, fingers were randomly divided into two groups; 11 were treated with three injections of HA around the tenorrhaphy site and 11 served as a placebo group and were treated with saline in the same way. The first dose was given at the time of tenorrhaphy and two additional doses were given at one-week intervals. A Kleinert rehabilitation protocol was employed postoperatively. Range of motion was assessed with total active and passive movement evaluation systems at 3 weeks, 3 months and long-term. Functional outcome was evaluated using the Strickland classification.

Results: There were no differences between the two groups in terms of range of motion at 3 weeks. However, at 3 months and long-term, a significant improvement was observed in fingers treated with HA compared to placebo.

Conclusion: This preliminary placebo-controlled study suggests that repetitive injections of HA can improve clinical outcomes presumably due to the effect on decreasing adhesions in primary tendon repairs.