Repeated administration of exogenous Sodium-hyaluronate improved tendon healing in an in vivo transection model

Goals and objectives: This study was designed to evaluate the effects of exogenous Sodium-Hyaluronate (NaH) on full thickness Superficial Digital Flexor Tendon (SDFT) rupture in the early phase of healing in rabbits. Methods: Forty White New Zealand mature male rabbits were randomly divided into two equal groups of injured treated and injured untreated. After full thickness tendon transection and surgical repair, using modified Kessler technique and running suture, the injured legs were casted for 14 days. Sodium-Hyaluronate was injected subcutaneously over the lesion on days 3, 7 and 10 post-injury (DPI). The control animals received normal saline injection following the same protocol. Weight of the animals, tendon diameter, ultrasonographic evaluations was conducted at weekly intervals. The rabbits were euthanized on 28 DPI and the tendons were assessed for macroscopic, histopathologic, ultrastructural, and percentage dry weight analysis. Results: Although there was no significant difference in the radiographs of the treated and untreated lesions, treatment significantly reduced tendon diameter, ultimate and yield strain and increased echogenicity and dry weight content of the injured tendons compared to those of the untreated ones. Treatment also significantly enhanced the maturation rate of the tenoblasts, diameter and density of the collagen fibrils. Conclusion: Treatment of NaH has been shown to be effective in restoring the morphological and biomechanical properties of lacerated SDFT of rabbits and may be valuable in the clinical trial studies. (C) 2012 Tissue Viability Society. Published by Elsevier Ltd. All rights reserved.