Safe Drill Trajectory for Anatomic Repair of Distal Biceps Tendon Through a Single Incision: A Cadaveric Study

Abstract

We sought to determine the safest drill trajectory to avoid injury to the posterior interosseous nerve (PIN) when performing a repair of a distal biceps tendon to an anatomic location through an anterior, single-incision approach using cortical button fixation. A standard anterior approach was performed in 10 cadaveric specimens to expose the distal biceps attachment. Three drill holes were made in the radial tuberosity from the center of the anatomic footprint for the distal biceps tendon insertion with the forearm fully supinated. Holes were made in 30° distal, transverse, and 30° proximal directions. Each hole was made by angling the trajectory from an anterior to posterior and ulnar to radial direction, leaving adequate bone on the ulnar side to accommodate an 8-mm tunnel for the purpose of docking the biceps tendon into bone. The proximity of each drill trajectory to the PIN was determined by making a second incision on the dorsum of the proximal forearm. A K-wire was passed through each hole, and the distance between the PIN and K-wire was measured for each trajectory. The distally directed drill hole placed the trajectory wire closest to the PIN (mean distance, 5.4 mm), contacting the K-wire in 3 cases. The transverse drill trajectory resulted in contact with the PIN in 1 case (mean distance, 7.6 mm). The proximal drill trajectory appeared safest, with no PIN contact (mean distance, 13.3 mm). In this cadaveric study, the proximal drill trajectory resulted in the widest clearance from the PIN. When performing repair of a distal biceps tendon to the anatomic location on the tuberosity, the drill trajectory from the center of the biceps footprint should be radial and proximal to provide the greatest separation between the drill guide and the PIN.