The cortical ring sign: A reliable radiographic landmark for percutaneous coracoclavicular fixation

• Published in: Journal of shoulder and elbow surgery 2010, Vol.19 (1), p.121-129
• Main Authors: Garrigues, Grant E., MD, Marchant, Milford H., MD, Lewis, Gemma C., BS, Gupta, Anil K., MD, MBA, Richard, Marc J., MD, Basamania, Carl J., MD
• Format: Article
• Language: English
• Subjects: acromioclavicular; Acromioclavicular Joint - anatomy & histology; Acromioclavicular Joint - diagnostic imaging; Acromioclavicular Joint - surgery; acromion; Arthroscopy - methods; Biological and medical sciences; Bosworth; Cadaver; clavicle; Clavicle - anatomy & histology; Clavicle - diagnostic imaging; Clavicle - surgery; coracoclavicular; Coracoid; Diseases of the osteoarticular system; Female; Fluoroscopy; Fracture Fixation, Internal - instrumentation; Fracture Fixation, Internal - methods; Humans; Male; Medical sciences; Minimally Invasive Surgical Procedures - methods; Orthopedics; Probability; ring; Scapula - anatomy & histology; Scapula - diagnostic imaging; Scapula - surgery; separation; Technology, Radiologic - methods
• ISSN: 1058-2746; 1532-6500
• DOI: 10.1016/j.jse.2009.04.002

Background For treatment of acute acromioclavicular separations, we have been using a reproducible radiographic view of the coracoid—the cortical ring sign—that we believe allows for placement of percutaneous coracoclavicular fixation safely and reliably in the center of the coracoid base, while avoiding the coracoid tip. This study evaluates the coracoid anatomy that the cortical ring sign represents, its utility for guiding fixation trajectory, and the proximity of neurovascular structures to this proposed trajectory. Materials and methods Kirschner wires were used to measure the orientation of the fluoroscopic beam in relation to the scapula and the proposed fixation trajectory using this radiographic view. Results The cortical ring sign is achieved by first directing the x-ray beam perpendicular to the medial border of the scapula in the parasagittal plane and 49° off the axis of the scapular spine in the axial plane, then fine-tuning until the coracoid cortical ring becomes evident. The nearest neurovascular structures to the fixation trajectory are the suprascapular artery and nerve (< 2 cm). Conclusion The cortical ring sign view targets the coracoid base and, as such, allows reliable, safe, percutaneous fixation in the center of the coracoid base. Level of Evidence Basic Science.