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.