Arthroscopic repair of triangular fibrocartilage tears: a biomechanical comparison of a knotless suture anchor and the traditional outside-in repairs.

Abstract

To compare the biomechanical strength of a knotless suture anchor repair and the traditional outside-in repair of peripheral triangular fibrocartilage complex (TFCC) tears in a cadaveric model. We dissected the distal ulna and TFCC from 6 matched cadaveric wrist pairs and made iatrogenic complete peripheral TFCC tears in each wrist. In 6 wrists, the TFCC tears were repaired using the standard outside-in technique using 2 2-0 polydioxane sutures placed in a vertical mattress fashion. In the other 6 wrists, we repaired the TFCC tears using mini-pushlock suture anchors to the fovea. The strength of the repairs was then determined using a materials testing machine with the load placed across the repair site. We loaded the repairs until a gap of 2 mm formed across the repair site, and then subsequently loaded them to failure. Thus, for each repair we obtained the load at 2-mm gap formation, load to failure, and mode of failure. At the 2-mm gap formation, the suture anchor repairs were statistically stronger than the outside-in repairs. For load to failure, the suture anchor repairs were also statistically stronger than the outside-in repairs. Failure in both techniques occurred most commonly as suture pull-out from the soft tissues. The all-arthroscopic suture anchor TFCC repair was biomechanically stronger than an outside-in repair. The suture anchor technique allows for repair of both the superficial and deep layers of the articular disk directly to bone, restoring the native TFCC anatomy. By being knotless, the suture anchor repair avoids irritation to the surrounding soft tissues by suture knots.