Long-Term Shoulder Function after Type I and II Acromioclavicular Joint Disruption

Background Acromioclavicular joint separations are very common lesions, with the majority falling into Rockwood classification type I and II. It is generally agreed that conservative treatment of these injuries leads to good functional results, although there are some studies that suggest these injuries are associated with a high incidence of persistent symptoms. Hypothesis Type I and II acromioclavicular joint disruption significantly impairs long-term shoulder function. Study Design Case series; Level of evidence, 4. Methods The shoulder function of 23 patients who were treated for type I or II acromioclavicular joint disruption was evaluated at a mean of 10.2 years after injury. The objective and subjective measures of the injured shoulder were assessed using Constant, University of California-Los Angeles Shoulder Scale, and Simple Shoulder Test scores and were compared with results of the uninjured shoulder. Results At an average follow-up of 10.2 years, 12 of 23 patients (52%) reported at least occasional acromioclavicular joint symptoms. The average Constant score for the injured shoulder was 70.5 and 86.8 for the uninjured shoulder (P < .001). The average University of California-Los Angeles Shoulder Scale score for the injured shoulder was 24.1 and 29.2 for the uninjured shoulder (P < .001). The average Simple Shoulder Test value for the injured shoulder was 9.7 and 10.9 for the uninjured shoulder (P < .002). The extent of acromioclavicular joint disruption and acromioclavicular joint width did not have any statistically significant influence on the shoulder functional scores. Conclusion Type I and II acromioclavicular joint disruptions impair long-term shoulder function in about half of patients 10 years after injury.