Biomechanical evaluation of 4 techniques of distal biceps brachii tendon repair.

BACKGROUND: Recent technical improvements have led the way to a resurgence of the single-incision approach for repair of distal biceps tendon injuries. There has been no biomechanical evaluation of all these techniques with comparison to the standard 2-incision bone tunnel technique.

HYPOTHESIS: There will be no difference under cyclic loading and ultimate failure between the 2-incision bone tunnel technique, suture anchor repair, interference screw, and EndoButton techniques for the repair of distal biceps tendon ruptures.

STUDY DESIGN: Controlled laboratory study.

METHODS: Sixty-three fresh-frozen cadaveric elbows were randomly assigned to 4 treatment groups (bone tunnel, EndoButton, suture anchor, interference screw). Cyclic loading was then performed from 0 degrees to 90 degrees at 0.5 Hz for 3600 cycles with a 50-N load. A differential variable reductance transducer was placed between the radius and distal tendon to determine displacement. The construct was then pulled to failure at 120 mm/min.

RESULTS: A multiple analysis of variance revealed no statistically significant difference for displacement among the 4 repair techniques. Displacement using the bone tunnel was 3.55 mm, EndoButton was 3.42 mm, suture anchor was 2.33 mm, and interference screw was 2.15 mm. There was a statistically significant greater load to failure with EndoButton (440 N) than suture anchor (381 N), bone tunnel (310 N), or interference screw (232 N) (P < .001).

CONCLUSION: The EndoButton technique had the highest load to failure.

CLINICAL RELEVANCE: These data demonstrate the EndoButton to be the strongest repair technique, with no failures during cycling at physiologic loads and with the largest load to failure. These findings are important in maximizing surgical results and stability and suggest that the construct can tolerate early postoperative active range of motion.