Anatomic acromioclavicular joint reconstruction

Acromioclavicular (AC) joint separation represents one of the most common shoulder injuries, with AC joint injuries accounting for 12% of all shoulder injuries in the overall population. The most common mechanism of this injury is a fall with a direct force to the lateral aspect of the shoulder and with the arm in an abducted position.

Depending on the magnitude of injury to the AC joint capsule and ligaments as well as to the coracoclavicular (CC) ligaments, these injuries can be classified by increasing severity as type I through type VI (according to Rockwood). ^, Typically, low-grade injuries such as type I or type II should be treated conservatively. Thus, current conservative management strategies show favorable outcomes, less complications and higher return to activity rates with a nonoperative treatment algorithm. ^, When facing high-grade injuries (types IV-VI), literature recommends surgery. ^{, ,} No overall consensus exists on treatment for type III dislocations according to Rockwood’s classification, as clinical studies failed to show significant benefit for surgical interventions. Thus, a trend toward initial nonoperative treatment is presently favored in most cases, even though functional impairment due to scapular dyskinesia or chronic pain remains concerning following conservative treatment. Some of these conservatively treated patients will have persistent pain and an inability to return to their sport or job. Subsequent surgical stabilization, albeit delayed, has still allowed return to sport or work in such cases. However, consideration of other factors, such as type of sport, timing of injury relative to athletic season, position in which the athlete competes, or throwing demands, may alter the procedure. Of interest, no differences between operative and conservative treatment have been observed in terms of shoulder strength, pain relief, throwing ability, or development of osteoarthritis (OA). Contrary, better cosmesis and longer sick leave may occur with operative treatment.

The highly variable severity of type III injuries led to a consensus statement published by the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine (ISAKOS) to further subdivide type III injuries, to more accurately indicate patients who may benefit from surgery : type IIIA injuries are considered stable without overriding of the clavicle on the cross-body adduction view and without significant scapular dysfunction, whereas type IIIB injuries present with horizontal instability and therapy-resistant scapular dysfunction.

In light of the controversy and clear lack of evidence supporting acute surgical management of grade III AC separations, we recommend that all patients be treated initially with 3 to 6 weeks of nonoperative management. Unfortunately, 20% of these patients still present with scapular dysfunction, even after successful completion of conservative treatment. Thus, a patient with a grade III AC separation qualifies for surgical reconstruction after a failed short course of nonoperative management as defined by persistent symptoms.

AC joint repair has a long history. Since 1917, when Cadenet first introduced his technique for AC joint instabilities, over 150 different techniques have been described, whereas a few of these techniques have been abandoned or re-invented secondary to high complication and clinical failure rates. However, none of these has been proven as gold standard. Currently proposed surgical approaches can be separated into three categories: (1) anatomic reconstruction of the conoid and trapezoid ligaments, (2) nonanatomic methods including reconstruction of coracoclavicular (CC) ligaments without or (3) with hardware and nonanatomic open reduction with internal fixation. ^, Most of the current techniques focus on reconstruction of the CC ligaments in reference to anatomic studies emphasizing the biomechanical importance of the CC ligaments for vertical stability of repairs of the AC joint. From a biomechanical perspective, the importance of the CC ligaments and AC ligaments in controlling superior and horizontal translation of the distal clavicle has been elucidated. In the past decade, a trend towards arthroscopic-assisted techniques has been observed. Among these, anatomic techniques focus on reconstruction of both the conoid and trapezoid ligaments. However, improved horizontal stability may further be facilitated by a reconstruction of the CC ligaments in an early stage after injury with an approach of clavicle and acromion, allowing subsequent healing of the torn AC and CC ligaments. Alternatively, an additional reconstruction of the AC ligaments may be performed, and it is advantageous especially in chronic instabilities with decreased healing potential of the AC ligaments.

We advocate the use of a separate, more robust graft source, semitendinosus tendon rather than the coracoacromial ligament, and an anatomic procedure to achieve optimal postoperative results. The anatomic coracoclavicular reconstruction (ACCR) enables simultaneous reconstruction of the CC ligaments (trapezoid and conoid) and the AC ligaments for optimized restoration of biomechanical function. This technique restores function of both the CC ligaments and the AC ligaments in an anatomic procedure with the use of an allogenic or autologous tendon graft (semitendinosus). ^{, ,}