Load to Failure for a Novel Scapholunate Bridge Augmentation Technique

Abstract

We sought to establish load to failure for a novel Bridge Augmentation technique using all-suture, knotless anchors to treat scapholunate interosseous ligament (SLIL) injury. Secondarily, we determined whether there exists any correlation between load to failure and either age or body mass index (BMI), and reported measurements based on sex.

We performed a cadaveric biomechanical study to evaluate our technique. Seven cadaveric specimens with no prior carpal instability/degeneration were included. After sectioning of the SLIL, the bridge augmentation was performed by placing one anchor in the scaphoid and one in the lunate, then affixing them to one another to bridge the scapholunate interval. Load to failure was assessed for each specimen, and mean load to failure was 91.8 N (standard deviation [SD] 25.1). A weak negative correlation was found between age and load to failure (r =  − 0.36), and a weak positive correlation between BMI and load to failure (r = 0.37). Mean load to failure in female specimens was 97.8 N (SD 11.5) and in male specimens was 83.7 N (SD 34.4).

Our results for load to failure for the bridge augmentation technique provide similar or superior results compared with many SLIL repair methods. Several existing repair techniques have load to failure ranging from 30 N to 91 N. Some techniques with extensive reconstruction or bulky extra-articular augmentation report higher load to failure but come with downsides of multiple bony tunnels and/or potential irritation of the radiocarpal articulation.

We present a biomechanically robust technique of bridge augmentation to treat SLIL injury using all-suture, knotless anchors. This novel method allows for minimal bone loss during placement, no bulky, extra-articular construct, and no risk of a hard body in the joint in the event of anchor pull-out.