Biomechanical and clinical outcomes after distal biceps tendon reattachment using an endo button technique and an interference screw.

Background: Rupture of the long head of the distal bifid biceps tendon is a rare injury, for which surgical anatomical repair should be considered in active patients. The aim of this study was to review our patients who benefited from the EndoButton technique via a single anterior approach, comparing the clinical outcomes with the contralateral uninjured side and assessing their quality of life. Our hypothesis was that an "anatomical" insertion, through an anterior approach, by reinserting the 2 distinct tendons on the radial tuberosity, would restore the supination ability of the forearm more effectively than flexion strength. Methods: This study included 25 patients who underwent surgery between June 2015 and January 2021. All patients underwent distal biceps reattachment using an endo-osseous fixation technique with the same device. Each patient completed a quality-of-life questionnaire and participated in biomechanical performance tests. Results: We observed a significant 14% reduction in strength during flexion on the operated side compared to the healthy side. However, no significant differences in strength were found for supination, extension, and pronation between the operated and nonoperated limbs in these same patients. In terms of endurance, flexion on the operated side tended to exhibit greater endurance than on the healthy side, while endurance in supination appeared similar between the operated and healthy sides. This finding held irrespective of whether the operated limb was dominant or nondominant. We also discovered a strong correlation between the time elapsed since surgery and differences in strength during both flexion and supination. Conclusion: The ultimate goal is to achieve an anatomical surgical repair to restore all functions and maximize patient outcomes. As demonstrated, we have obtained good clinical results with EndoButton repair and a single anterior approach. The results in terms of strength and endurance are similar to those reported in the literature, and all our patients are satisfied. No postoperative complications were found.