Anatomical considerations for safe retractor placement in distal biceps repair: a cadaveric study of the posterior...

Distal biceps tendon repair is a common procedure with a risk of iatrogenic nerve injury, including the posterior interosseous nerve (PIN). This study aimed to define the anatomical relationship of the PIN to key elbow landmarks, particularly the radial tuberosity, and to identify safe zones for retractor placement during surgery.

Twenty-nine fresh cadaveric upper extremities were dissected by a fellowship-trained shoulder and elbow surgeon. Measurements included the bifurcation point of the radial nerve into the PIN and superficial radial nerve. We measured the PIN's distance from the radiocapitellar joint (RCJ) and its relation to the radial tuberosity in both pronation and supination. The safe positioning of retractors relative to the radial tuberosity was also evaluated.

The radial nerve bifurcated approximately 5 ± 3 mm proximal to the RCJ. The PIN entered the supinator (Arcade of Frohse) at 22 ± 1 mm distal to the RCJ. It was located a mean of 13 ± 2 mm from the radial border of the radial tuberosity in pronation and 19 ± 2 mm in supination. In all specimens, the PIN distal to the arcade was surrounded by muscle, with no direct contact with bone. Safe retractor placement was ulnar to the tuberosity proximally and radial distally in supination.

Supination increases the separation between the PIN and the tuberosity by ~ 5 mm, supporting ulnar proximal and radial distal retractor placement (narrow right-angled/Langenbeck) to reduce iatrogenic injury.

IV (Anatomical cadaveric study).