The relation of the coracoclavicular ligament insertion to the acromioclavicular joint: a cadaver study of relevance to lateral clavicle resection.

Resection of the lateral end of the clavicle is a common procedure for arthrosis of the acromioclavicular joint (AC-joint). However, no anatomical data on the distance between the insertions of the coracoclavicular ligaments and the AC-joint have been reported. In 36 cadaver shoulders (18 male), we studied the relation between the AC-joint and the insertions of the joint capsule, trapezoid and conoid ligaments. The distance from the AC-joint to the medial end of its capsule was, on average, 0.7 cm (0.4-0.9) cm in women and 0.8 (0.4-1.2) cm in men. In women, the trapezoid ligament began, on average, at 0.9 (0.4-1.6) cm and ended at 2.4 (2.0-2.8) cm and in men, it began at 1.1 (0.8-1.6) cm and ended at 2.9 (2.1-3.8) cm medial to the AC joint. The corresponding figures for the conoid ligament were 2.6 (2.0-3.7) cm and 4.7 (3.9-6.2) cm. A resection of 1 cm of the lateral clavicle detaches 8%, a resection of 2 cm 60% and a resection of 2.5 cm 90% of the trapezoid ligament. We recommend a maximum resection of 1 cm of the lateral clavicle because a resection of 2 cm or more may cause postoperative AC-joint instability and related pain.