An Analysis of Factors Associated With Failure of Tendon Repair in the Canine Model

Purpose: The canine model is commonly used for flexor tendon repair research. The purpose of this study was to analyze the factors, including laceration mode (partial and complete), suture techniques, therapy methods, and weight-bearing status, associated with tendon repair rupture or gap formation in the canine model in vivo. Methods: We reviewed the factors associated with repair failure among 624 flexor tendon repairs in zone II from 242 dogs reported previously from our institution, including both partial and complete lacerations. Results: We found that weight-bearing due to failure of postoperative immobilization was the most important factor influencing tendon repair rupture or gap formation. Conclusions: As has been noted clinically, in our canine model failure and gapping of a flexor tendon repair was primarily the result of uncontrolled loading. Rehabilitation strategies that reduce the risk of catastrophic loading of the repair are critical to reducing the experimental failure rate when using dogs for flexor tendon research. Similar strategies may also reduce such failures in humans.