A safe zone for resection of the medial end of the clavicle.

Medial clavicle resection is indicated when symptoms of sternoclavicular instability or degeneration remain disabling despite nonoperative management. Preservation or reconstruction of the costoclavicular ligament (rhomboid ligament) is essential to prevent subsequent instability of the remainder of the medial clavicle. Eighty-six cadaveric sternoclavicular joints were dissected to determine the distance (safe resection length [SRL]) from the inferior articular surface of the medial end of the clavicle to the most medial insertion of the costoclavicular ligament (rhomboid ligament). The mean SRL was 1.2 +/- 0.3 cm in men and 1.0 +/- 0.2 cm in women. Resection of 1.0 cm of the medial clavicle would result in no or minimal disruption of the costoclavicular ligament in 84% of men, and resection of 0.9 cm of the medial clavicle would result in no or minimal disruption of the costoclavicular ligament in 89% of women. We recommend that these amounts be used as a guide to safe resection of the medial clavicle but that the costoclavicular ligament be exposed to allow certainty of preservation.