The AC joint is surrounded by a thick joint capsule and AC ligaments, and is also stabilized by the coracoclavicular (CC) ligaments as well. When these soft tissue structures are injured, typically through sports injuries or trauma, then an AC joint injury (also known as a separated shoulder) may occur.

Symptoms of an AC Joint Injury

AC joint injuries, or shoulder separations, can vary in severity depending on which ligament(s) are injured. Low-grade injuries typically involve ligament sprains only, and not ligament ruptures. Another variant of a low-grade shoulder separation is if the AC ligaments are torn, but the CC ligaments are still intact. With the CC ligaments intact, the AC joint will remain in proper alignment. High-grade injuries typically involve ruptures of both the AC and CC ligaments. In these high-grade injuries, the AC joint becomes destabilized, and the pull of the surrounding muscles typically results in deformity at the AC joint.

High-grade AC joint injury (shoulder separation). Note the superior displacement of the clavicle relative to the acromion, indicating that both the AC and CC ligaments are ruptured.

In terms of symptoms, patients typically experience pain at the AC joint, and a visible deformity in high-grade cases. There may be a sensation of instability as well, particularly with activities that involve load on the shoulder. It is also common to have pain at night with sleep, especially when sleeping on the affected shoulder.

Non-Surgical Treatment of AC Joint Injury

We recommend beginning with non-surgical treatment for low-grade AC joint injuries. This typically involves an initial period of immobilization to allow for soft tissue healing. Once enough healing has occurred, patients then begin physical therapy to help regain range of motion, strength, and function.

Surgical Treatment of AC Joint Injury

In high-grade AC joint injuries or low-grade injuries that continue to be symptomatic despite non-surgical treatment, surgery to stabilize the AC joint may be considered. In my practice, this is typically performed in a minimally-invasive, arthroscopic-assisted fashion to repair the CC ligaments. Depending on the severity and chronicity of the injury, a tendon graft may also be used to reconstruct the CC ligaments and augment the repair.

X-rays of high-grade AC joint injury (shoulder separation) before and after surgical repair.

Recovery After AC Joint Surgery

For a comprehensive reading of the expected post-operative recovery, including restrictions, physical therapy progressions, and return to work/sport guidelines after AC joint repair/reconstruction surgery, please see our corresponding protocol on our physical therapy protocols page.