Intraoperative Application of Hyaluronic Acid in Achilles Tendon Repair: A Retrospective Cohort Study on Short-Term...

Background and Objectives: This study aimed to investigate the effect of intraoperative hyaluronic acid (HA) application on short-term functional outcomes after open surgical repair of Achilles tendon rupture. Materials and Methods: This retrospective cohort study included 102 patients screened at three tertiary centers (January 2023-October 2024). After applying the exclusion criteria, 64 patients were analyzed (32 HA, 32 control), with group allocation based on the intraoperative use of HA. The primary outcomes were the American Orthopaedic Foot and Ankle Society (AOFAS) Score and the Achilles Tendon Total Rupture Score (ATRS), evaluated at 3, 6, and 12 months; the Short Form 36 (SF-36) Physical Component Summary (PCS) and Mental Component Summary (MCS) scores, assessed at 6 and 12 months; and physical-performance tests (heel-rise endurance, single-leg hop distance, and calf muscle strength), performed at 6 and 12 months. Complications, including re-rupture, wound infection, and delayed wound healing, were also recorded. Results: At 6 months, the HA group had higher AOFAS scores (mean difference: 9.0, 95% CI: 6.3-11.7, p = 0.008) and ATRSs (mean difference: 7.0, 95% CI: 3.8-10.2, p = 0.008) than the controls. The differences were smaller but remained significant at 12 months (AOFAS mean difference: 5.0, 95% CI: 2.5-7.5, p = 0.034; ATRS mean difference: 4.0, 95% CI: 1.1-6.9, p = 0.034). The SF-36 PCS and MCS scores were also superior in the HA group at 6 and 12 months (all p < 0.05). The physical-performance tests (heel-rise endurance, single-leg hop, calf strength) showed significant mean differences, with the HA group scoring higher at both timepoints (all p < 0.05). Complication rates were low and not significantly different between groups (all p > 0.05). Conclusions: Intraoperative HA application during open Achilles tendon repair was associated with improvements in short-term functional recovery, general health status, and physical performance without increasing complication rates. These findings support the use of HA as a safe adjunct to optimize tendon gliding; however, prospective randomized controlled trials are needed to confirm these results.