Acromioclavicular Joint Sprain
The acromioclavicular (AC) joint is made up of the outer end of the collarbone and the outer corner of the shoulder blade (the acromion). This joint is held together by many strong ligaments and is typically very stable. Overstretching of these ligaments due to trauma can result in an AC joint sprain, which often includes a visible deformity. While the initial injury is painful, and the deformity may create cosmetic issues, most AC joint sprains are easily treated with physical therapy and do not result in long term disability.
Falling on the tip of the shoulder or an outstretched hand, or a blow to the outside of the shoulder can cause an AC joint sprain.
– Participation in contact sports, accidents, trauma, previous AC joint injuries.
– Shoulder pain/soreness to the touch.
– Swelling and bruising over the joint.
– Visible “step off” deformity.
– Limited range of motion.
– Pain with reaching overhead or across the body.
At Home Diagnostic Tests
– Observe step-off deformity at AC Joint.
– Piano key sign (video).
– AC Joint Compression Test (video).
At Home Care
– Avoid irritating movements.
– Comfort care: ice, NSAIDs as needed.
When to Seek Help
Contact your physical therapist if there is a visible deformity, or if pain does not subside within 7 days. If there is pain along the collarbone, seek medical assessment for a possible clavicle fracture.