Biomechanical and Clinical Evaluation of a Modified 3‐Loop Pulley Suture Pattern for Reattachment of Canine Tendons to Bone

Abstract

To describe a modified 3-loop pulley suture pattern for the reattachment of canine tendons to bone along with a biomechanical comparison with the locking-loop suture. In vitro biomechanical study and clinical case report. Biomechanical study: 10 paired gastrocnemius tendons and calcaneii harvested from 5 canine cadavers. a Doberman with avulsion of the gastrocnemius tendon of insertion. Biomechanical study: paired tendons were reattached to the calcaneus with either a modified 3-loop pulley pattern or a locking-loop pattern. Tensile loading to failure was performed. A direct, non-contact, method of gap measurement, using digital video, was used to measure gap formation. Load required to initiate gap formation (defined as load at a 1 mm gap) and to produce a 3 mm gap was evaluated in addition to maximum load and gap at failure. Mean (+/-SEM) 1 mm gap loads were 31.0+/-4.2 and 17.2+/-2.5 N, mean 3 mm gap loads were 49.1+/-2.4 and 28.9+/-3.2 N, and mean maximum loads were 72.9+/-4.3 and 55.8+/-2.2 N for the modified 3-loop pulley suture and the locking-loop suture, respectively. These differences were statistically significant (P<.05). The gap at failure was similar for both repairs. The clinical case remained sound 7 months postoperatively. A modified 3-loop pulley pattern is biomechanically superior to a locking-loop pattern for reattachment of the canine gastrocnemius tendon to bone and may be suitable for clinical use. Tendon repairs with a gap >3 mm are reported to be at increased risk of rupture during the first 6 weeks postoperatively. A modified 3-loop pulley pattern resists gap formation better than a locking-loop pattern.