Utilization of the bicipital groove axis for confirming alignment of the humerus with transepicondylar and ulnar shaft axes during intramedullary nailing

Objective: Intramedullary nailing is the preferred surgical treatment of humerus shaft fractures. The purpose of this study was to investigate the relationship between the bicipital groove and specific anatomical landmarks in achieving correct alignment of the humerus during intramedullary nailing, and to describe these anatomical landmarks. Methods: Thirty (15 right; 15 left) total upper cadaver extremities were used in this study. After the anatomical landmarks were identified and marked, humeral head axis, transepicondylar axis, ulnar shaft axis, bicipital groove axis, and angular measurements of these were obtained. Results: The mean angle between the bicipital groove axis and transepicondylar axis was 48.17°±12.35° (range: 20.10° to 74.6°). The mean angle between the bicipital groove axis and ulna diaphysis axis was 41.82° ±11.56° (range: 17.91° to 68.27°). The mean angle between the humeral head axis and bicipital groove axis was 20.53°±3.90° (range: 11.85° to 31.81°). The mean retroversion angle between the humeral head axis and transepicondylar axis was 27.52±11.37° (range: 4.26° to 49.36°). The mean angle between the humeral head axis and ulna diaphysis axis was 61.73° ±12.08° (range: 33.97° to 86.37°). The mean torsion angle was 62.58º±11.28 ° (range: 40.74º to 85.74°). Conclusion: Measurement and utilization of the relationship between the bicipital groove, ulna diaphysis and transepicondylar axes may be used for restoring humeral rotation.