Use of cortical buttons for the fixation of the distal biceps tendon in combination with the double-incision technique—the relationship between the drill trajectory and the proximity to the posterior interosseous nerve: a cadaveric study

The aim of this cadaveric study was to investigate different defined drill trajectories through the radial tuberosity for the placement of a cortical button and their proximity to the posterior interosseous nerve (PIN) by using the double-incision technique. A total of 10 elbows from 5 fresh entire cadavers were used in this study. Detachment of the distal biceps tendon was performed to simulate its rupture. A standardized double-incision approach was performed, and the radial tuberosity was exposed in full pronation. A drill hole was applied perpendicular through the center of the tuberosity. Another 8 drill holes were applied with the same starting point at the tuberosity with defined trajectories. A cortical button was then placed through the center hole. The distances between the PIN and the exit holes of the different trajectories were measured. The cortical button was analyzed regarding muscle entrapment as well as its closest distance to the PIN. Contact of the PIN and the drill hole was observed for 6 of the 9 trajectories; only the proximal-ulnar, ulnar, and ulnar-distal trajectories had no contact with the PIN in any of the experiments. No contact of the cortical button and the PIN was observed for the ulnar and distal-ulnar drill trajectories only. The minimal distance to the PIN was 1.6 mm for both. Because of the potential risk of PIN injuries, the use of cortical button fixation in combination with the double-incision approach cannot be recommended.