Suture bridge transosseous equivalent repair is stronger than transosseous tied braided-tape

This study biomechanically compares two methods of supraspinatus repair: single row transosseous braided-tape (BT) and suture bridge transosseous equivalent (SBTE) with 2 medial anchors and 2 lateral anchors. The purpose is to test the hypothesis that BT provides superior or equal biomechanical strength compared to SBTE.

Nine pairs of frozen cadaveric shoulders were selected and both repair techniques were tested on each pair, using a biomechanical testing unit to measure cyclic loading and ultimate load to failure. Moreover, tendon displacement was measured using the percentage of footprint exposed during the cyclic loading phase.

Mean specimen age was 71 years (6 males, 3 females), and mean volumetric bone mineral density was 134 mg/cm³. BT mean ultimate load was 266 ± 81 Newton (N) compared to 398 ± 69 N for SBTE and this difference of 131 N was statistically significant p = 0.025. There was a strong positive correlation between bone mineral density and SBTE construct ultimate load. The difference between the percentage of footprint exposed after cyclic loading of the two repairs was statistically significant with the exception of the 10-80 N load (p < 0.05). The failure mode was suture cutout through the tendon in 88% (7/8) of specimens for both techniques.

SBTE repair with bone anchors provides superior biomechanical strength compared to BT repair in terms of ultimate load and cyclic loading. The tendon-suture junction is the weakness of both methods. These models simulate a complete tear with total loss of contact with rotator interval and infraspinatus. Future studies could focus on a more isolated physiologic supraspinatus tear pattern.

Basic science study (Level II).