Evaluation of suture caliber in flexor tendon repair

This biomechanical study investigated the effect of suture caliber variation on tensile strength in 3 types of 2-strand flexor tendon repairs. Each type of repair was constructed with 5-0, 4-0, 3-0, and 2-0 braided polyester suture. Linear distraction was performed on 120 repaired human cadaveric flexor digitorum profundus tendons until tensile failure occurred. Ten trials of each repair construct were tested. Analysis of variance revealed significant main effects of caliber and technique. Mean repair strength increased as suture caliber increased. A 4-0 suture was 66% stronger than a 5-0 suture, a 3-0 suture was 52% stronger than a 4-0 suture, and a 2-0 suture was 51% stronger than a 3-0 suture. The technique effected repair strength only with the larger 2-0 and 3-0 suture calibers, which tested the technique's capacity to hold the tendon.