Biomechanical properties of four circumferential flexor tendon suture techniques

Purpose: We introduce 2 interlocking circumferential flexor tendon suture techniques: the interlocking cross stitch and the interlocking horizontal mattress repair and biomechanically tested them against 3 commonly used methods. Methods: Thirty-two deep digital flexor tendons harvested from sheep hindlambs were transected sharply. These were repaired without a core suture using 4 different circumferential repair techniques: group 1, simple running group 2, cross-stitch; group 3, interlocking cross-stitch; group 4, intelocking horizontal mattress. All tendons were tested to failure at a distraction rate of 20 mm/min. Load to 2-mm gap formation, stiffness, load to failure, and method of failure all were assessed. Results: The mean load to 2-mm gap formation was 22.8, 20.7, 20.0, and 26.1 N for groups 1, 2, 3, and 4, respectively. The mean stiffness was 7.6, 8.1, 8.7, and 10.1 N/mm, and the mean load to failure was 30.9, 42.1, 49, and 52.9 N for groups 1, 2, 3, and 4, respectively. There was no statistically significant difference between groups 2 and 3. Group 4, however, was statistically better than the others in all measured parameters (except group 3 in load to failure). Conclusions: The interlocking horizontal mattress was the best performer overall, with statistically greater loads to failure, 2 mm gap formation, and stiffness. The technique could be considered for use in any patient likely to begin an early postoperative finger mobilization program. Copyright (C) by the American Society for Surgery of the Hand.