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PEARLS & PITFALLS – SURGICAL TECHNIQUE
Description of a Novel, Effective and Reproducible Portal for Arthroscopic Distal Clavicle Excision: Technique and Cadaveric Validation
An anterior portal is established at this location, and using a sharp pin to mimic an arthroscopic device, the subacromial space was entered. The portal with the intact pin was then carefully dissected both anteriorly and superiorly to examine the coracoacromial ligament and AC joint (Fig. 3). Further, the distance and angle of the pin from the AC joint axis in both the anterior and posterior aspects of the joint was measured to validate the placement of the instrument.
Results
The average angle from the central portion of the AC joint to the pin anteriorly was 6 degrees. Average distance (offset) from the same point anteriorly averaged 3.2mm. Posterior offset averaged 2.8mm, and the posterior average angle from the central portion of the AC joint to the pin was 3.6 degrees. Dissection of all portals revealed pin placement above the CA ligament in all five specimens, and that there was no iatrogenic damage to this structure.
Conclusions
This study demonstrates a safe, effective, and reproducible way to establish the anterior portal for arthroscopic distal clavicle excision. On cadaveric dissection, the average distance to the center of the AC joint is less than the width of a standard arthroscopic burr, allowing for safe and adequate resection of the distal clavicle. The is especially important, in that the most difficult portion to resect, the posterosuperior aspect of the distal clavicle, can be easily and reproducibly accessed using this technique.
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Additional Author: Jonathan T. Bravman, MD
Purpose
Justin J. Mitchell, MD
Department of Orthopaedic Surgery University of Colorado School of Medicine
Aurora, CO, USA
The purpose of this research is to provide an anatomic description for creating an anterior portal that preserves local anatomy, and is both safe and effective for glenohumeral and acromioclavicular joint access using reproducible anatomic landmarks. This technique has recently been published, and has been clinically reliable for our practice. The described portal is both safe and effective, allowing the surgeon direct access to the AC joint while also allowing access to the glenohumeral joint. This description can be important for surgical planning, as distal clavicle excision often occurs at the end of the arthroscopic shoulder procedure, and anterior portals are infrequently planned to accommodate this.
Methods
Five cadaveric shoulder specimens were examined in a laboratory setting. Using reproducible subcutaneous anatomic landmarks of Neviaser’s point, the clavicle, the acromion and the coracoid, cutaneous markings are made (Fig. 1). A line perpendicular to the clavicle that connects Neviaser’s point to the most lateral aspect of the coracoid is then drawn (Fig. 2). Along this line, a ruler is used to mark a distance 1.5cm distal to the anterior edge of the clavicle, which typically localizes the entry point to position just superior and lateral to the tip of the coracoid. This point also places a planned anterior portal directly in line with the AC joint, but also allows for access to the glenohumeral joint for examination and treatment.
10 ISAKOS NEWSLETTER 2015: Volume I