A New Model for Repair of the Achilles Tendon in the Rat

ABSTRACT

The Sprague-Dawley rat is an excellent model for studies of Achilles tendon repair. Most researchers use a modification of the Kessler technique for suture repair of the Achilles tendon in rats. While this technique provides adequate strength, early mobilization is not recommended. Prior to healing, the load will be borne completely by the suture repair, subjecting it to rupture. To prevent this complication, investigators employing the Kessler repair often immobilize the operative extremity with a cast or splint. This has also been shown to be detrimental to the peak load borne by the tendons prior to rupture. A double-loop locking technique of suture repair for rat Achilles tendons is favored over the modified Kessler technique. As force is applied across the repair, the suture pulls on the tendon, sharing the load. This allows for early mobilization of repaired tendons, with minimal risk of rupture. Additionally, no immobilization is required for the operative extremity. One hundred repairs have been performed using this double-loop locking technique. All animals have been able to mobilize with minimal limp immediately after recovering from anesthesia, and there have been no ruptures. No other complications have occurred (hematoma, seroma, infection, dehiscence). This technique of tendon repair is ideal for use in studies of tendon repair in the rat, since it is easy to perform and eliminates the need for immobilization of the operative leg.