Modes of failure of knotted and knotless suture anchors in an arthroscopic bankart repair model with the capsulolabral tissues intact.

The purpose of this study was to assess failure modes of knotless and knotted anchors in a Bankart repair model with the capsulolabral soft tissues intact. Previous reports used a model stripped of soft tissues. In 8 matched pairs of cadaver shoulders, a Bankart lesion was repaired arthroscopically using either 2 Bio-SutureTak anchors (Arthrex, Naples, Florida) or 2 Bioknotless anchors (Mitek, Westwood, Massachusetts). The shoulders were mounted with the repaired capsulolabral tissues attached to a custom sinusoidal clamp, and were tested in cyclic loading (20-80 N, 100 cycles, 0.5 mm/s) and then load to failure (1.25 mm/s). Cut-through at the suture-tissue interface (23/32 anchors) was more common than pullout at the anchor-bone interface (9/32) as a mode of failure (P = .02). Failure at the suture-tissue interface occurred in 10/16 knotted and 13/16 knotless anchors. Mean (SD) ultimate load of knotted vs knotless anchors was 125.3 (67.4) N and 96.9 (95.1) N, respectively. Mean (SD) stiffness of knotted vs knotless anchors was 20.9 (6.4) N/mm and 19.8 (8.6)N/mm, respectively. We concluded that both knotted and knotless anchors fail most often at the suture-tissue interface. The tested model with the capsulolabral tissues intact is distinct from previous models, which tested the anchor-bone interface only.