Minimally invasive endoscopic reconstruction technique of acute AC-joint dislocations: a cadaver study

The treatment of acute Rockwood type III AC-joint dislocations is controversial. Problems related to open surgery are soft tissue healing, residual instability and the necessity of hardware removal. After non-operative therapy the cosmetic result may be problematic and in some cases symptomatic instabilities occur. The goal of the present cadaver study was to develop a new, minimally invasive technique for acute AC-joint reconstructions and to analyse its potential risk for neurovascular injuries. The surgical technique was based on an arthroscopically assisted reconstruction of the coracoclavicular ligaments with a suture anchor (Arthrex, Naples, FL, USA) and a supplemental stabilization of the AC-joint capsule with a suture cerclage (Fibre Wire 2, Arthrex) performed on ten cadaveric shoulder specimens. After surgery all specimens were dissected to analyse the anatomy of the coracoclavicular ligament complex, the position of anchors and sutures and to measure the distance to the neurovascular structures at risk. The supraspinatus muscle was never injured by the Neviaser approach. The insertion of the suture anchors never failed, resulting in a secure and reproducible anchor position. The mean distance between the coracoid and suprascapular nerve was 1.8 cm (1.5-2.2), between the coracoid and the suprascapular artery 1.5 cm (1.3-1.9). These structures were never injured. The resulting force vector of the suture located between the anchor and the drill hole was close to the anatomic force vector of the coracoclavicular ligament complex. The suture cerclage was always correctly positioned. The presented technique is at minimal risk for the surrounding neurovascular structures and allows for a minimally invasive and anatomically correct reconstruction of the AC-joint. Further biomechanical analysis is needed to evaluate the strength of the reconstruction technique. The proposed technique might be a reasonable alternative to existing invasive techniques of open reconstruction of acute type III AC-joint dislocations in high-demand patients.