Optimally strong tendon repair using braided polyethylene strand: 2-Strand heavy-gauge locking technique vs. multiple-strand technique

Abstract

Background We conducted an in vitro study to investigate the strongest tensile force for tendon repair using a braided polyblend suture strand material, employing a 2-strand heavy-gauge side-locking loop technique, comparing it with other multiple-strand repair techniques. Methods Using the United States Pharmacopeial Convention (USP) 2 and 5-sized braided polyblend strands, 3 repair techniques were evaluated after suturing transacted bovine gastrocnemius tendons: 2-strand side-locking loop, 4-strand Savage, and 6-strand Yoshizu-1 techniques. Ultimate tensile force and mode of failure at strand rupture were examined (n = 5 for each combination). Findings The ultimate tensile forces was observed with USP2-side-locking loop (mean 402 N), USP5-side-locking loop (mean 748 N), USP2-Savage (mean 552 N), and USP2-Yoshizu-1 Groups (mean 598 N). The USP5-side-locking loop Group had proportionally greater ultimate tensile force than the USP2-side-locking loop Group. However, with the number of strands doubled or tripled, resulting strengths were only 1.4 times or 1.5 times greater. The mode of failure was rupture at the locking loop portion in all side-locking loop Group samples, pull-through of the strand from the tendon in all Savage Group samples, and either pull-through of the strand from the tendon (40%) or rupture at the knot (60%) in the Yoshizu-1 Group samples. Interpretation Greater numbers of strands do not achieve proportionally greater strong tensile force in the repaired tendon. When employing the side-locking loop technique for secured locking formation, the heavier strand yields markedly greater tensile force even with only 2 strands, and thus greater holding ability.