Modified Prusik knot versus whipstitch technique for soft tissue fixation in anterior cruciate ligament reconstruction: a biomechanical analysis

Abstract

Appropriate graft tension and secure graft incorporation in bone tunnels are essential for successful anterior cruciate ligament (ACL) reconstruction using hamstring tendon autografts. Permanent viscoplastic elongation in response to cyclic loading in the early postoperative period and the interposition of suture material in the tendon-bone interface might negatively affect graft function and rigid graft incorporation in the bone tunnels. A modified Prusik knot is an alternative option to the commonly used whipstitch technique for soft tissue fixation in ACL reconstruction. This is a controlled laboratory study. Sixteen formalin-fixed human cadaver semitendinosus tendons were armed with a modified Prusik knot or a whipstitch and tested in a load-to-failure test with a constant displacement rate of 1 mm/s, 14 in the cyclic loading test with 100 cycles from 10 to 50 N followed by 100 cycles from 10 to 75 N. The modified Prusik knot showed smaller force-induced displacements and higher stiffness of the entire construct in the load-to-failure test. Smaller preconditioning displacements were the only significant differences in the cyclic loading test. The modified Prusik knot has equal or superior mechanical properties and provides a larger area in the tendon-bone interface without suture material compared with the whipstitch technique.

Effect of suturing the femoral portion of a four-strand graft during an ACL reconstruction

“…On the other hand, suturing the hamstring tendon graft in a whipstitch fashion could lead to a permanent viscoplastic elongation of the graft due to slippage of the suture within the tendon tissue [18,22].…”

Do Needleless Knots have Similar Strength as the Krackow Suture? An In Vitro Porcine Tendon Study

“…Several needleless grasping sutures, namely the modified Prusik knot, Wittstein suture loop, rolling hitch, modified finger-trap, and modified rolling hitch, have been proposed in recent years owing to inherent disadvantages of the previous techniques, including tendon damage caused by passing a needle, time consumption, and the potential risk of needlestick injury [7,8,12,15,17]. These needleless techniques have been shown to reduce cost, decrease exposure to needles, and shorten surgical time [7,8,10,12,17].…”

“…These needleless techniques have been shown to reduce cost, decrease exposure to needles, and shorten surgical time [7,8,10,12,17].…”

“…Several studies have evaluated the biomechanical properties of the needleless suture techniques [2,10,12,15]. Krappinger et al [12] compared the modified Prusik knot with the whipstitch, and found that the modified Prusik knot had similar mechanical properties as the whipstitch technique.…”

“…Krappinger et al [12] compared the modified Prusik knot with the whipstitch, and found that the modified Prusik knot had similar mechanical properties as the whipstitch technique. Su et al [15] proposed the modified finger-trap for securing tendon grafts, and showed that the modified finger-trap provided better biomechanical properties than the Krackow stitch.…”