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

Abstract

Purpose: 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.

Methods: 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.

Results: 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).

Conclusions: 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.

Clinical relevance: 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.