Biomechanical comparison of suture and screw fixation in PCL avulsion with variable bone quality

Various fixation techniques, including screws and suture-based methods, are used for posterior cruciate ligament (PCL) avulsion fractures. This study compared the biomechanical effects of different suture configurations in simulated PCL avulsion fractures. Twenty cadaveric knees were assigned to four fixation groups: antegrade screw (A), 1 suture tape with 2 tunnels (B), 2 suture tapes with 2 tunnels (C), and 2 suture tapes with 3 tunnels (D). Biomechanical testing included cyclic loading and load-to-failure tests, with elongation, stiffness, yield load, and failure modes recorded. No significant differences were found between groups (p > 0.05). Mean elongation ranged from 10.1 ± 2.9 mm (B) to 21.9 ± 15.9 mm (D), while mean yield load varied from 375.6 ± 110.9 N (C) to 428.6 ± 197.6 N (B). Fragment breakage was common in Groups A and D, while suture cut-through occurred in Groups B and C. Across all groups, bone mineral density (BMD) significantly correlated with yield load (r = 0.511, p = 0.021) and elongation (r = -0.553, p = 0.0110.Suture-based techniques provided comparable biomechanical performance to screws, and increasing suture tapes or tunnels did not enhance fixation strength. Bone quality should be considered when planning fixation and rehabilitation.