Suture Slippage Is Influenced by Suture Type and Bone Density in a Knotless Lateral Row Rotator Cuff Repair: A Biomechanical Analysis

Purpose To evaluate the influence of suture material and bone density on suture slippage in knotless lateral row anchors used in rotator cuff repair. Methods Analysis of 3 different suture materials loaded into a single lateral row anchor and tested in 2 different densities (osteoporotic and normal) of Sawbone models was conducted. Testing was carried out using perpendicular traction of loaded sutures in a load cell with assessment of maximum force (N) and displacement (mm). After testing completion, the blocks were visually analyzed, and cut‐through length (mm) was measured. Results Suture type ( P < .001) and bone density ( P < .001) have a significant effect on maximum force tolerance by the construct. FiberTape can withstand a much higher maximum force irrespective of bone densities. Displacement data collected from the load cell shows that suture type ( P < .001), but not bone density ( P = .228), plays a significant role, with FiberTape having a comparatively lower displacement. Evaluation of cut‐through data shows that bone density ( P = .006), but not suture type ( P = .94), has a significant effect on cut‐through. Conclusions Suture slippage in knotless lateral row fixation is significantly influenced by the suture material and the underlying bone density. Constructs using high‐strength suture tape showed higher load‐to‐failure and lower displacement compared with conventional sutures. Clinical Relevance Our study shows that the weakest link in a knotless repair is the lateral row, and this can be influenced by the type of suture used in the construct along with the density of bone.