What is acromioclavicular (AC) arthritis? How do you diagnose it?
It is arthritis of the AC joint, a structure that is minimally mobile but still prone to inflammation. This,
in turn, may lead to rotator cuff irritation through the downward protrusion of bony spurs into the tendon.
Pain of AC arthritis is initially vague, localized to the joint, and possibly radiated to the shoulder, anterior
chest, and neck. With time, it may become associated with crepitus and swelling. Pain can be elicited by
direct compression of the joint, or by stress maneuvers.
These involve (1) cross-body adduction of the arm behind the back (which produces pain in the AC joint at the end of adduction); (2) movement of the arm across the chest (so that the hand touches the opposite shoulder); and (3) cross-arm maneuver (the arm is forward flexed and then adducted across the body).
These tests are positive when they elicit pain in the AC joint.
It is arthritis of the AC joint, a structure that is minimally mobile but still prone to inflammation. This,
in turn, may lead to rotator cuff irritation through the downward protrusion of bony spurs into the tendon.
Pain of AC arthritis is initially vague, localized to the joint, and possibly radiated to the shoulder, anterior
chest, and neck. With time, it may become associated with crepitus and swelling. Pain can be elicited by
direct compression of the joint, or by stress maneuvers.
These involve (1) cross-body adduction of the arm behind the back (which produces pain in the AC joint at the end of adduction); (2) movement of the arm across the chest (so that the hand touches the opposite shoulder); and (3) cross-arm maneuver (the arm is forward flexed and then adducted across the body).
These tests are positive when they elicit pain in the AC joint.