Risk of Posterior Interosseous Nerve Injury During Distal Biceps Tendon Repair Using a Cortical Button

PURPOSE: To evaluate the possibility of posterior interosseous nerve (PIN) injury during cortical button deployment and seating associated with bicortical drilling and passage of the cortical button across the distal cortex when repairing a distal biceps rupture in a cadaveric model. METHODS: Each cadaver was placed in the supine position with the arm extended. A single 4 cm transverse incision was made in the region of the radial tuberosity, 3–4 cm distal to the antecubital fossa flexion crease, and dissected down to the radial tuberosity. A #2 looped nonabsorbable suture was used to baseball stitch the musculotendinous junction to the distal 2.5 cm end of the tendon. A 3.2 mm cannulated drill bit (Arthrex) was used to create a bicortical drill hole in the center of the radial tuberosity aiming 30° ulnar to maximize the distance from the PIN. Fluoroscopy was used to confirm drill placement in the radial tuberosity for all specimens. The posterior aspect of the elbow in all cadavers was subsequently dissected out to directly visualize how far the cannulated drill was from the PIN. RESULTS: Twelve cadavers, average age 57.4 years (range, 27–83 years), were dissected. During deployment, the cortical button contacted the PIN directly in 6 extremities. The cortical button came within 6 mm of the PIN in eleven extremities. In 8 specimens, the cortical button was within 2 mm of the PIN. The PIN was caught directly under the cortical button in one specimen. CONCLUSIONS: Placement of a biceps cortical button bicortically when repairing a distal biceps tendon may increase the risk of injury to the PIN during cortical button deployment and seating. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.