Editorial Commentary: Why We Have To Respect The Anatomy In Acromioclavicular Joint Surgery And Why Clinical Shoulder Scores Might Not Give Us The Information We Need!

Over the past decade, the interest in acromioclavicular (AC) joint research has experienced a revolutionary increase. Biomechanical and anatomic studies have been carried out to investigate and obtain a better understanding of the function of this joint. The reason for this huge investigational effort is the fact that we do not have any gold standard for the treatment, diagnosis, or follow-up of patients with acute or chronic AC joint injuries. This is reflected by the huge number of over 160 different surgical techniques described in the literature. So far, we have a variety of anatomic procedures, nonanatomic procedures, and nonanatomic procedures with open reduction and internal fixation, with a significantly better clinical outcome for anatomic techniques. Because of this wide variety, it is hard and nearly impossible to compare clinical data. Within the past 5 years, we have focused not only on the vertical instability but also, more and more, on the horizontal instability and tried to understand the rotational component of this joint with the importance of scapulothoracic motion. The evolutionary advantage of bipedalism with the support of the clavicle compared with quadrupedalism allows us to lift our arms for overhead activities. Therefore, we need an intact sternoclavicular and AC force transfer, described as the "strut function," to give a resistance against the thorax when abducting the arm over 90°. Once we have an interruption in this force transfer, we believe that it is the most important aspect in AC joint surgery to try to anatomically restore this joint's anatomy. For this reason, we have changed our practice in the past few years in line with the newly derived data, by addressing the coracoclavicular ligaments as well as the AC capsule to restore horizontal and vertical stability but also allow for physiological rotation and movement.