Akademik Veri Yönetim Sistemi
APPLIED SCIENCES-BASEL, cilt.16, sa.6, 2026 (SCI-Expanded, Scopus)
Rotator cuff suture anchors have traditionally been inserted at the 45 degrees "deadman" angle, but this recommendation was largely derived from single-row constructs and may not reflect the biomechanics of contemporary double-row suture bridge repairs. This study compared the biomechanical performance and stress distribution of medial row anchors inserted at 45 degrees versus 90 degrees in a double-row suture bridge construct. Sixteen ovine humeri with intact infraspinatus tendons were randomized to 45 degrees or 90 degrees medial anchor insertion (n = 8 each), and double-row suture bridge repair was performed using 3.5 mm metallic and PEEK anchors. Specimens underwent uniaxial tensile testing (10-N preload, 5 mm/min) to failure, measuring yield load, failure load, displacement, stiffness, and energy absorption; additionally, a CT-based finite element model of the human humerus assessed von Mises stress, strain, and deformation under 200 N loading. Mean failure load was 161.96 +/- 50.99 N for 45 degrees and 185.61 +/- 60.97 N for 90 degrees (p = 0.447), and stiffness was 31.63 +/- 8.18 N/mm versus 36.79 +/- 9.26 N/mm (p = 0.291). Displacement at failure was greater with 90 degrees insertion (8.11 +/- 0.51 mm vs. 6.65 +/- 0.83 mm; p = 0.002), while energy absorption was higher but not significantly different (p = 0.255). Finite element analysis demonstrated lower bone von Mises stress with 90 degrees insertion (14.03 MPa) compared with 45 degrees (24.77 MPa), with similar deformation. In double-row suture bridge repair, 90 degrees medial anchor insertion provides comparable fixation strength to that at 45 degrees while reducing bone stress, suggesting a biomechanical advantage.