Subpectoral proximal humeral anatomy: Guidance to decrease risk of fracture following subpectoral biceps tenodesis.

BACKGROUND

Biceps tenodesis is used for a variety of shoulder and biceps pathologies. Humeral fracture is a significant complication of this procedure. This cadaveric anatomy study sought to determine the cortical thickness of the humeral proximal shaft to identify the optimal technique to decrease unicortical drilling and reduce the risk of fracture.

METHODS

A computed tomography (CT) of eight cadaveric humeral specimens was obtained with a metallic marker placed at the site of subpectoral tenodesis. These scans were examined to define the cortical thickness of the subpectoral region of the humerus and determine angular safe zones for reaming.

RESULTS

At the standard point of a subpectoral tenodesis, a mean angle relative to the coronal plane of 29.2° medially and 21.6° laterally from the deepest portion of the bicipital groove avoided unicortical drilling with a 7 mm reamer. These values varied slightly 1 cm proximal and distal to this level. The thickest regions of cortex in the subpectoral humerus correspond to the ridges of the bicipital groove.

DISCUSSION

To avoid unicortical tunnels, surgeons should limit deviation from the perpendicular approach to no more than 23° relative to the coronal plane medially and 11° relative to the coronal plane laterally.