Effect of the suture augmentation on the stability and strength of ulnar collateral ligament reconstruction: The anchor and bone tunnel methods.

Background: The initial fixation strength of the ulnar collateral ligament (UCL) reconstruction is increased by combining a suture augmentation (SA). However, no reports have investigated the stability of UCL reconstruction with SA across multiple elbow flexion angles and the influence of SA on the stability and failure strength of the anchor and bone tunnel methods. This study aimed to compare the displacement against a valgus load at multiple elbow flexion angles of the anchor and bone tunnel methods between with and without SA, and to compare the failure strength between these methods with SA. We hypothesized that the combination of SA reduced the displacement, and the failure strength was comparable between the anchor and Ito methods with SA.

Methods: Eight fresh-frozen cadaveric upper extremities were used. To evaluate the displacement against valgus load, the valgus stability tests at multiple flexion angles were performed for four UCL reconstruction methods: anchor method, anchor with SA, bone tunnel, and bone tunnel with SA. The load-to-failure test was performed to evaluate the failure strength of the anchor and bone tunnel methods with SA. P < 0.05 was considered significant in tests of statistical inference.

Results: The displacements of the anchor method with SA at 30°, 60°, and 90° of flexion were significantly smaller than those without SA. Regarding comparing the bone tunnel method with and without SA, a significant difference was observed at only 30° of flexion. There was no significant difference in the failure strength between the anchor and bone tunnel methods with SA.

Conclusion: The combination of SA reduced the displacement against a valgus load at multiple flexion angles, and the failure strength was comparable between the anchor and bone tunnel methods with SA. Combining SA may increase the initial fixation strength in both the anchor and bone tunnel methods.