Histologic and magnetic resonance image evaluation in acromioclavicular joint osteoarthritis

INTRODUCTION: Little is known about the development of specific acromioclavicular joint osteoarthritis. Its histologic alterations are controversial, and radiologic alterations are seen in asymptomatic people. The objective of this study was to evaluate histologically the distal clavicle subchondral bone and to analyze magnetic resonance images in patients with painful and nonpainful acromioclavicular joint osteoarthritis. METHODS: An observational, analytical, and cross-sectional study with a control group was conducted. Between August 2018 and June 2019, we analyzed a total of 41 patients. Group 1 consisted of patients with pain in the acromioclavicular joint (symptomatic osteoarthritis), and group 2 consisted of patients without pain in the acromioclavicular joint (asymptomatic osteoarthritis). RESULTS: Twelve of the 15 patients with acromioclavicular joint pain (group 1) were female, 13 presented distal clavicle edema on magnetic resonance imaging, and 9 had subchondral bone edema on histologic examination. Patients with acromioclavicular joint pain had longer shoulder pain duration than patients without pain. Women were more likely to have acromioclavicular joint pain compared with men. Patients with edema on magnetic resonance imaging showed a greater chance of presenting pain in the acromioclavicular joint in comparison with patients without edema. CONCLUSION: Women had a higher chance of presenting with acromioclavicular joint pain than men. Patients with edema on magnetic resonance imaging were more likely to present with pain than patients without edema. Patients with acromioclavicular joint pain had longer shoulder pain duration than patients without pain, and subchondral bone edema on histologic examination was more frequent in patients with pain.