An AC joint injury is a sprain or separation of the small joint at the top of the shoulder where the collarbone meets the acromion, most often from a fall onto the shoulder. Symptoms can develop gradually or after a specific injury, so early evaluation matters when function starts to decline.
Most AC joint injuries are low-grade sprains that heal with conservative care: a short period in a sling, ice, anti-inflammatory medication, and physical therapy as the pain settles. Surgery is considered mainly for high-grade separations, where the collarbone is badly displaced, or for pain and weakness that persist after a full course of non-surgical treatment.
Below, we walk through the anatomy involved, the symptoms and causes we most often see, how we diagnose an AC joint injury, and the full range of treatment options, from the simplest to the most involved.