Compression Suture Staple Repair of Simulated Gluteus Medius Partial Tendon Tears Provides Increased Contact Pressure Compared With Stepwise Bridged Repair

Purpose To examine the contact mechanics of 2 different suture anchor configuration constructs for gluteus medius repair in partial‐thickness tears and to define an optimal distance for anchor placement in a biomechanical model. Methods Trochanteric bone was simulated using polyurethane foam blocks, and a polyurethane rubber was used as a surrogate for the gluteus medius tendon tissue. As the rubber remained partially attached to the foam, this design simulated a partial‐thickness tear without any retraction of the tendon tissue. A pressure sensor was used to collect contact data. Repairs were performed with knotless suture anchors. Three different 2‐anchor repair interval distances (10, 15, and 20 mm) were first tested to define the optimal distance for anchor placement. We then performed 2 different 3‐anchor repairs (stepwise bridged and compression suture staple) using the optimal distance. Pressure data were collected and compared between 3‐anchor groups. Results Results from the 2‐anchor interval distance testing showed an overall significant effect for contact force ( P < .001), area ( P < .001), and pressure ( P = .01), with 15 mm being the optimal distance to exert the most pressure. Results from the 3‐anchor testing at 15 mm between anchors showed that contact pressure on the surrogate tendon was significantly ( P = .04) greater for the compression suture staple technique (208.5 ± 61.6 kPa) compared with the stepwise bridged technique (143.4 ± 41.4 kPa). Conclusions In this biomechanical study, the compression suture staple technique exerted more pressure than the stepwise bridged repair technique at time 0 with no cyclic loading. Additionally, 15 mm had the greatest contact pressure of those examined for anchor placement using knotless suture anchors for these repairs. Clinical Relevance By studying the contact mechanics of different suture anchor configurations, we determined which setup may provide better compression of the tendon onto the bone.