Acromioclavicular (AC) joint injuries account for up to 50% of all shoulder injuries, with an overall incidence of 9.2 injuries per 1,000 person-years in young athletes. These injuries most commonly result from a direct blow to the acromion in an adducted shoulder. The AC capsuloligamentous structures initially fail, followed by failure of the coracoclavicular (CC) ligaments when there is sufficient force. The classification of AC joint injuries was described by Rockwood6dgrade I and grade II injuries are typically treated nonoperatively, whereas grade IV, grade V, and grade VI injuries are typically treated operatively. The mode of treatment for grade III injuries is currently controversial; however, many surgeons offer surgery acutely to high-level athletes and manual laborers with grade III injuries in addition to patients whose shoulders become chronically symptomatic.
Transfer of the coracoacromial ligament to the distal clavicle was first performed by Weaver and Dunn in 1972 as a method to restore AC joint stability in patients with AC joint dislocations. The so-called Weaver-Dunn method of AC joint reconstruction has since undergone several modifications because of significant complication rates and poor clinical results. Recently, anatomic coracoclavicular ligament reconstruction (ACCR) with soft-tissue grafts has become a popular method of reconstruction because it yields superior biomechanical strength and stability when compared with the Weaver-Dunn method. In 2006 Mazzocca randomly allocated 42 fresh-frozen cadaveric shoulders into 3 reconstruction groups looking at time-zero load to failure: (1) ACCR with allograft, (2) arthroscopic suture sling, and (3) open modified Weaver-Dunn technique. The open modified Weaver-Dunn reconstruction resulted in significantly increased laxity and anteroposterior translation compared with either the ACCR technique with tendon graft or the arthroscopic suture sling technique. In addition, the ACCR technique afforded improved posterior stability compared with the arthroscopic suture sling technique. ACCR was therefore found to be the most stable of the 3 tested AC reconstruction methods.
It has since been theorized that because ACCR techniques with soft-tissue grafts more closely approximate the native biomechanics of the intact state, these tech- niques may result in improved clinical results and patient satisfaction. The purpose of this study was to report the clinical and structural outcomes after ACCR with free tendon allografts in patients with grade III and grade V AC joint dislocations. We hypothesized that primary ACCR in patients with grade III and grade V AC joint dislocations would provide excellent clinical and structural outcomes after a minimum 2-year follow-up period.