Local treatment with ascorbic acid accelerates recovery of post-sutured Achilles tendon in male Wistar rats

Tendon rupture is a very frequent accident involving average people and high-performance athletes. Clinical studies describe tendon recovery as a painful and slow process involving different biochemical and histological events. Ascorbic acid (AA) is a potent antioxidant as well as an important cofactor for collagen synthesis. In the current study, we evaluated if local treatment with AA is able to promote tendon repair in tenotomized rats. Animals were submitted to Achilles tendon rupture followed by surgical suture. Control and AA groups received in loco injection of saline solution (0.9% NaCl) and 30 mM AA, respectively. Histological and functional recovery of Achilles tendon tissue was evaluated at 7, 14, and 21 days post-surgery. Hematoxylin/eosin staining and collagen fluorescence analysis showed intense disarrangement of tendon tissue in the saline group. Tenotomized animals also showed hypercellularity in tendon tissue compared with non-tenotomized animals. The Achilles functional index (AFI) showed a significant decrease of tendon functionality in tenotomized animals at 7, 14, and 21 days post-surgery. AA accelerated tissue organization and the recovery of function of the Achilles tendons. The beneficial effect of AA treatment was also observed in the organization of the collagen network. Data presented in the current work showed that in loco treatment with AA accelerated the recovery of injured Achilles tendon post-surgery.

Serial clinical and MRI examinations after arthroscopic rotator cuff reconstruction using double-row technique.

PURPOSE: Rotator cuff reconstruction using arthroscopic double-row technique enables a better repair of the anatomical footprint at the tendon insertion. Objective of this serial study was to illustrate structural and functional results during recovery following double-row reconstruction. METHODS: Forty-five patients with mid-sized ruptures of the supraspinatus tendon were assessed prospectively and underwent arthroscopic surgery using the double-row technique. Rupture localization, size, form, and extent of retraction were recorded intraoperatively. Clinical and MRI follow-up examinations were carried out for all patients after 6, 12, 26, and 52 weeks. A A standard protocol was used during the follow-up examinations to determine tendon integration, signal changes in the tendon, extent of bone marrow edema near the enclosed absorbable suture anchors, muscle changes. The clinical results were correlated with the MRI appearance. RESULTS: After 26 weeks, the Constant score (CS) showed a highly significant increase for the first time with a value of 78 (p < 0.001). Tendon integration according to Sugaya showed a left shift over time, with higher CS-values for lower Sugaya classifications. Significant improvements in strength were first measured between the 26-week and 52-week follow-ups (9->19/p < 0.001). Highly significant improvement (p < 0.001) of the tendon signal and the fatty infiltration was found in the same time interval. The hypotrophy showed slight improvement, while a highly significant reduction of the bone marrow edema was found between weeks 12 and 26 (p < 0.001). There were no re-ruptures after week 26. CONCLUSIONS: The present serial study showed that it took 26 weeks to reach a significant clinical improvement concerning CS. With regard to tendon healing, no further deterioration of the structural results occurred between week 26 and week 52 postoperative. There were slightly but not significant better clinical results according to the the Sugaya classification. However, parameter "strength" was significantly increased between weeks 26 and 52. This was consistent with a significant decrease in the signal intensity at the repaired tendon site, an additional improvement in the fatty infiltration, and the atrophy according to Thomazeau in the same time interval. LEVEL OF EVIDENCE: I.