Safe distances in coracoclavicular stabilization of high-grade acromioclavicular joint injury: a cadaveric study

Regarding treatments for acute high-grade acromioclavicular (AC) joint injury, combined coracoclavicular (CC) ligament stabilization and AC capsule repair are associated with the risk of iatrogenic neurovascular injury. However, previous studies have only evaluated the distances from the coracoid base to the neurovascular structure in intact AC joints; thus, it is questionable whether the distances from the existing evidence are reliable. This study aimed to measure and compare the distances from the coracoid base and tip to the neurovascular bundle in the beach chair, supine, and lateral decubitus positions in cadavers with high-grade AC joint injury. This study included four male and four female full-body fresh-frozen cadavers. We created high-grade AC joint injuries in 8 right and 8 left shoulders, and measured the distances from the anteromedial borders of the coracoid base and tip to the lateral border of the neurovascular structure in the horizontal, oblique, and vertical planes using cadavers in the beach chair, supine, and lateral decubitus positions. The average distances from the coracoid base to the neurovascular structure were shortest in the lateral decubitus position, with distances in the horizontal, oblique, and vertical planes of 39.93 ± 9.13, 26.29 ± 7.68, and 32.03 ± 8.87 mm, respectively. All distances were affected by body position, except for the distance in the beach chair and supine positions in the vertical plane. When performing CC stabilization for acute high-grade AC joint injuries, the lateral decubitus position may provide a smaller anatomical safety margin compared with the supine and beach chair positions in this cadaveric model.