Suture Configurations With Greater Tendon Purchase Show Increased Time-Zero Fixation Strength in Endoscopic Proximal Hamstring Repair.

Abstract

To compare the biomechanical performance of 4 common suture configurations, simple suture, horizontal mattress, Krackow, and modified Mason-Allen, in endoscopic repair of proximal hamstring tendon avulsions. Twenty-four cadaveric proximal hamstring tendons were randomized to 1 of the 4 repair groups (simple, horizontal mattress, Krackow, and Mason-Allen; n = 6 each). All constructs underwent uniaxial load-to-failure testing after preconditioning using a mechanical testing system. Primary outcomes included ultimate failure load (N) and linear stiffness (N/mm). Failure modes were recorded. Ultimate failure load was higher for Krackow (283.1 ± 67.9 N; 95% confidence interval [CI], 220.3-345.8) compared with simple suture (141.2 ± 44.6 N; 95% CI, 99.9-182.5; P = .002) and for Mason-Allen (282.5 ± 102.8 N; 95% CI, 187.4-377.6) compared with simple suture (P = .013). Horizontal mattress also showed greater failure load than simple suture (239.7 ± 68.9 N; 95% CI, 176.0-303.4; P = .018). CIs for Krackow, Mason-Allen, and horizontal mattress overlapped. Linear stiffness did not differ significantly among configurations (all P > .05). The predominant failure mode was suture pull-through at the tendon-suture interface (75% of specimens). Suture configurations with greater tendon purchase (Krackow, Mason-Allen) provided nearly double the failure load compared with simple sutures. Horizontal mattress sutures also provided comparable strength to locking patterns, highlighting a technically feasible alternative when portal access limits locking configurations in endoscopic repair. These biomechanical findings suggest that locking configurations, when achievable endoscopically, may enhance repair strength and reduce vulnerability to failure. The comparable performance of the horizontal mattress highlights a practical option when traditional locking patterns are not technically feasible. As endoscopic hamstring repair continues to evolve, optimizing suture configuration represents a key opportunity to improve repair robustness.