The modified finger-trap suture technique: A biomechanical comparison of a novel suture technique for graft fixation

Purpose The purpose of this study was to compare the tendon graft holding power of the newly devised modified finger-trap (MFT) suture technique with other currently used sutures. Methods We used 40 fresh-frozen porcine flexor profundus tendons randomly divided into 4 groups of 10 specimens. The experimental procedure was designed to assess percent elongation of the suture-tendon construct across four different tendon-grasping techniques: MFT suture, Krackow stitch, locking SpeedWhip stitch (Arthrex, Naples, FL), and nonlocking SpeedWhip stitch. The suture configurations of the MFT suture and Krackow stitch were completed with a No. 2 FiberWire suture (Arthrex). The locking SpeedWhip and nonlocking SpeedWhip stitches were completed with a loop of No. 2 FiberWire suture and a FiberLoop needle (Arthrex). Each tendon was pre-tensioned to 100 N for three cycles and then cyclically loaded to 200 N for 200 cycles. Finally, each tendon was loaded to failure. Percent elongation, load to failure, and mode of failure for each suture-tendon construct were measured. Results During the pre-tension phase, the MFT suture had the smallest percent elongation ( P = .021) of the suture-graft construct (13.5% ± 1.9%) compared with the Krackow (16.9% ± 1.2%), locking SpeedWhip (17.6% ± 0.6%), and nonlocking SpeedWhip (33.3% ± 5.6%) stitches. During cyclic loading, the MFT suture also showed a significantly smaller percent elongation ( P = .037) of the suture-graft construct (27.8% ± 4.9%) than the Krackow (35.8% ± 5.4%), locking SpeedWhip (33.7% ± 5.4%), and nonlocking SpeedWhip (43.8% ± 7.8%) stitches. The load to failure and cross-sectional area were not significantly different across all the suture groups. Conclusions The newly devised MFT suture provided better percent elongation and equal load to failure compared with the Krackow and SpeedWhip suture techniques tested in this in vitro biomechanical evaluation. Clinical Relevance The MFT suture is a simple method that is an attractive alternative to the Krackow and SpeedWhip suture techniques for tendon graft fixation in ligament reconstruction.