A comparative analysis of the biomechanical behaviour of five flexor tendon core sutures.

Five core suture techniques were compared by static tensile testing in vitro. Fifty porcine tendons were used. The core sutures were performed with 3-0 or 4-0 braided polyester suture (Ticron) and the over-and-over running peripheral sutures with 6-0 monofilament polypropylene (Prolene). The core sutures were: (1) Pennington modified Kessler (3-0), (2) Double Pennington modified Kessler (3-0), (3) 4-strand Savage (3-0), (4) 4-strand Savage (4-0), and (5) 6-strand Savage (4-0). Repairs were compared as paired in regard to one variable: the number of core suture strands, the suture calibre, or the suture configuration. Biomechanical differences between the repair groups started during the linear region, with the yield force and stiffness increasing along with the number of core suture strands. All three variables influenced the strain at the yield point. Thus, the strength of the intact repair can be improved by modifying the core suture. In all repairs gap formation started near the yield point after failure of the peripheral suture. The yield force represents the strength of the intact repair composite and should be considered the strength of the tendon repair.