Proximity of the posterior interosseous nerve during cortical button guidewire placement for distal biceps tendon reattachment.

Purpose: To assess the distance between the posterior interosseous nerve (PIN) and a distally and ulnarly directed guide pin for placement of a cortical button to reattach a distal biceps tendon.

Methods: We used 10 fresh frozen cadaveric upper limbs without deformities and identified the PIN through a dorsal approach. We performed a single incision anterior surgical approach, detached the biceps tendon, and drilled a 1.6-mm K-wire from the base of the biceps tendon insertion in 3 different trajectories, sequentially, measuring the following drilling angles: 30° distal and 30° ulnar, 30° ulnar, and 30° distal. In each testing scenario, we measured the minimum distance in millimeters between the tip of the K-wire and the PIN using a digital caliper through the dorsal incision.

Results: The mean and median distances from the guide wire to the PIN in each testing trajectory were each significantly different from each other, with the 30° ulnar direction leading to the greatest distance from the nerve.

Conclusions: We found that the 30° ulnar drilling direction resulted in a significantly greater distance from the guide wire to the PIN, in comparison with the distal-ulnar and the distal-only trajectories.

Clinical Relevance: This study helps define the safe trajectory for guide wire placement in bicortical fixation of distal biceps tendon injuries.