Relationship between MRI and clinical findings in the acromioclavicular joint

To determine the relationship between the magnetic resonance (MR) appearance of the acromioclavicular (AC) joint and the physical findings.

A total of 116 consecutive patients underwent routine MR imaging (MRI) of the shoulder over an 18-month period. All MR studies were interpreted by a blinded, experienced musculoskeletal radiologist. Eleven variables were studied: the presence of osteophytes; fluid in the joint; fluid outside the joint; high signal in the clavicle or in the acromion; fluid in the subacromial bursa; irregularity of the joint margins; bulging of the capsule; widening of the joint; the age of the patient; and the presence of a rotator cuff tear. The clinical information was supplied by an experienced shoulder surgeon blinded to the MRI findings. A control group of 23 normal volunteers was also studied.

The only statistically significant correlation ( P=0.0249) was between high signal in the distal clavicle and degenerative changes found clinically. A weaker relationship existed between fluid in the joint and the clinical examination and between increasing degenerative changes and advancing age. Otherwise, no material relationship was found between any of the other MR abnormalities and the clinical picture.

There appears to be no real correlation between the MR appearances and the clinical findings in the AC joint.