AC Joint Arthritis

Acromioclavicular (AC) joint arthritis is degeneration of the small joint where the clavicle meets the acromion at the top of the shoulder. It is one of the most common forms of shoulder arthritis and frequently develops after AC joint separation injuries or from repetitive overhead loading.

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Typical Recovery Time

Injection relief often lasts months; surgery recovery 2–3 months

Symptoms

•Pain at the top of the shoulder (AC joint line)
•Pain with cross-body movements (e.g., reaching across the chest)
•Tenderness directly over the AC joint
•Pain with bench press or push-up exercises
•Swelling or bony prominence at the joint

Common Causes

•Prior AC joint separation or trauma
•Repetitive overhead loading (weightlifting, manual labor)
•Age-related wear
•Distal clavicle osteolysis in weightlifters
•Inflammatory arthritis

Treatment Options

1Activity modification (avoiding cross-body and overhead loading)

2NSAIDs

3AC joint corticosteroid injection (highly effective)

4Physical therapy

5Distal clavicle resection (Mumford procedure) for refractory cases

When to See a Doctor

See a provider if the top of your shoulder is specifically tender with cross-body movements — AC joint injection is both diagnostic and therapeutic.

Frequently Asked Questions

What is AC joint arthritis?

AC joint arthritis is wear and tear of the small joint at the top of the shoulder where the collarbone meets the shoulder blade. Over time, the cartilage breaks down and causes pain and stiffness. It is common in people who lift weights or perform repetitive overhead activities.

What causes AC joint arthritis?

It is usually caused by long-term overuse, prior injuries, or natural aging of the joint. Activities like weightlifting, especially bench press, can speed up the process. Previous AC joint injuries can also increase the risk.

What symptoms should I expect?

Pain is typically felt at the top of the shoulder and worsens with cross-body movements or lifting. Some people notice swelling or tenderness over the joint. Over time, the pain can become more constant with activity.

How is AC joint arthritis treated?

Treatment usually starts with activity modification, anti-inflammatory medications, and physical therapy. Injections may help reduce pain if symptoms persist. Surgery is rarely needed but can be considered in severe cases.

When can I return to activity?

Most people can continue modified activity while managing symptoms. Return to full activity depends on pain control and strength. Many athletes return within a few weeks once symptoms improve.