Diminished space in the acromioclavicular joint in forced arm adduction as a radiographic sign of degeneration and osteoarthrosis.

The purpose of this study was to examine the acromioclavicular joint by radiography under forced arm adduction to demonstrate diminished joint space as a sign of cartilage degeneration and osteoarthrosis. A total of 192 right and left joints were investigated in 96 healthy working men. There were three main results from the manoeuvre: in 135 of the 192 joints the space was reduced, in 33 joints it was unchanged, and in 24 joints the joint space was increased. In 43 joints (22% of the total) a marked reduction of the joint space to 1 mm or less occurred during the manoeuvre; in the remaining 92 joints with space reduction the reduction was less pronounced. A narrow acromioclavicular joint space during forced adduction of the arm indicates cartilage thinning and may be interpreted as a sign of osteoarthrosis.