Cochrane in CORR®: Surgical Versus Conservative Interventions For Treating Acromioclavicular Dislocation of The Shoulder in Adults

Importance of the Topic Injuries to the acromioclavicular joint exist upon a wide spectrum, and its many classification systems reflect the range of different non-operative and operative treatment options available [1]. One commonly used classification system describes acromioclavicular injuries as having six types, grouping them as a function of the status of the acromioclavicular and the coracoclavicular ligaments, and, when both are disrupted, classifying them based on the severity and direction of the distal clavicle’s displacement [5]. Surgeons generally agree that Types 4 through 6 (complete disruptions of the acromioclavicular and the coracoclavicular ligaments, with more than 100% displacement of the clavicle) benefit from surgical treatment in active patients who are fit for surgery and that Types 1 and 2 (sprain of the acromioclavicular ligament, and tear of the acromioclavicular ligament without a tear of the coracoclavicular ligament, respectively) generally are well-managed without surgery. Surgeons often disagree about whether and when patients with Type 3 injuries should or should not be managed surgically because of the availability of multiple treatment options, including more than 35 non-operative methods and nearly 150 surgical techniques, and insufficient evidence from randomized controlled trials addressing when each treatment type is indicated for acromioclavicular dislocation [1, 8]. In this updated Cochrane review, Tamaoki and colleagues [9] analyzed five randomized control trials and one quasi-randomized control trial, to ascertain patient-important outcomes, including physical function, pain, return to former activities, time to recovery, quality of life, treatment failure, and adverse events from non-operative and operative treatment of 357 patients with acromioclavicular joint injuries. Overall, the authors found, albeit at low-quality evidence and with arguably outdated techniques, no short-term differences between treatment arms in shoulder function, return to sport/work, and/or quality of life [9]. Upon Closer Inspection In our opinion, the studies captured in this Cochrane review were so hampered by serious sources of bias that we cannot endorse guiding clinical practice based on their findings; indeed, the authors of this Cochrane review themselves identify the serious risks of bias and imprecision in the estimates they made [9]. The main shortcomings included the inclusion of studies with a range of injury types and lack of a standardized classification schema. For example, half of the included studies referenced injuries as “displaced” or “non-displaced” based on the width of the clavicle—when the ever-changing bone morphology of the clavicle, and its influence by age and sex, is well known [3, 7]. Instead, a more-appropriate definition references the coracoclavicular distance, which serves as a reproducible reference point from which to assess clavicular displacement, and infer injury severity of the acromioclavicular and/or coracoclavicular ligaments [5]. More troubling, however, is that half of the included studies were published more than 30 years ago, and as such, this “updated” review does not keep pace with the technological advances in trauma and sports medicine, namely the increasing trend towards minimally-invasive, arthroscopic approaches with loop suspensory fixation devices augmented with biological auto/allograft. In fact, this review examines hook plates, coracoclavicular screws, acromioclavicular pins, and threaded-wire technology. These are, as the authors themselves say, “outdated devices with known high risks of complications” [9]. This alone would appear to be a disqualifying methodological flaw, but, as noted already, it was not the only one. Given the several issues highlighted, and considering the low-quality of the included evidence, the absence of substantial differences in patient-reported outcomes, and the fact that the implant-associated problems likely were a function of the outdated technologies employed in the source studies, we would caution readers against placing too much stock in the key findings of this Cochrane review. This is no fault of the authors (or of the Cochrane collaboration). We are in desperate need of updated randomized trials on this common, important clinical problem. Take-home Messages In a world of increasing surgical sub-specialization, we believe that acromioclavicular joint injuries arguably should be treated by surgeons well-versed with principles of musculoskeletal trauma, arthroscopy/sports medicine, and/or anatomic repair or reconstruction. A well-performed repair or reconstruction can restore bi-directional acromioclavicular joint stability either soon after the injury [4, 11] or months later [2, 4], either with or without use of arthroscopy [6] in ways that respect the local anatomy [10]. Establishing the feasibility of a multi-center randomized control trial that is cognizant of these tenets, and specifically, pilots the comparison of non-operative (sling immobilization) with arthroscopic, anatomical acromioclavicular joint stabilization for Rockwood Type 3 injuries is of paramount importance. Until then, as trials of such magnitude often require major financial and workforce resources, to name a few, insight into the ideal treatment strategy can be gleaned from the creation of and/or collective contribution to large, publicly-funded, and accessible shoulder registry datasets.

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