Resorbable Suture Is a Suitable Surgical Repair Material in a Rat Achilles Rupture and Repair Model.

Background: Treatments for Achilles tendon rupture (ATR) are insufficient because they often do not result in full recovery and return to activity. There is no universal standard protocol for ATR, with surgeons using different repair techniques and materials. Some surgeons prefer nonresorbable (NR) suture due to the superior tensile strength, and others use resorbable (RES) because they decrease foreign body reactions. Methods: To establish a model for future interventional studies, we performed ATRs on 3-month-old female Sprague-Dawley rats using either NR or RES suture to repair the tendon and collected tissues at 1 and 2 months. Results: No significant differences in mechanical or material properties as a function of suture type were noted. Independent of suture type, tendons were wider at 1 month and both wider and thicker at 2 months, resulting in large increases in cross-sectional area (CSA) at each time point. The repaired tendons were stronger than the uninjured contralateral tendons at 1 month, but their strength decreased from the first month to the second despite increasing in CSA during this time, indicating progressive deterioration of tissue quality. Conclusions: Our data suggest that without loads in excess of body weight, the healing process becomes maladaptive after repair regardless of suture material. Level of Evidence/Clinical Relevance: These experiments provide Level I pre-clinical evidence showing that RES suture performs at least as well as NR in all physiological measures following repair, indicating it is the preferable repair material for ATR. See Instructions for Authors for a complete description of levels of evidence.