Acromioclavicular Joint

Overview

The acromioclavicular (AC) joint is where the clavicle meets the acromion at the top of the shoulder. Over time, this joint commonly develops bone spurs and arthritis from normal wear and tear. It may also become painful following a direct injury to the shoulder. Although these are two different conditions, both involve the same joint and are treated differently.

AC Joint Arthritis – Presentation

AC joint arthritis commonly develops from normal wear and tear but may occur earlier in active individuals who perform repetitive heavy lifting, weight training, or bench pressing. Typical symptoms include pain directly on top of the shoulder, tenderness over the AC joint, pain with cross-body adduction (such as applying deodorant to the opposite underarm), and discomfort during bench press, push-ups, or overhead lifting. The AC joint is frequently involved as part of the shoulder impingement process.

Conservative Treatment

Treatment includes activity modification, anti-inflammatory medication, and corticosteroid injection into the AC joint. When the injection completely relieves the pain, it confirms that the AC joint is a primary source of the patient's symptoms. If symptoms persist or additional pathology is suspected, an MRI may be obtained.

Surgical Treatment

When conservative treatment no longer provides adequate relief, or the patient simply wants to resolve the problem rather than continue managing it with repeated injections and activity modification, an arthroscopic distal clavicle excision is recommended. This procedure removes a small portion of the end of the clavicle. I often tell patients this is probably the most reliable operation I perform in the shoulder. Success rates approach 95%, and the procedure itself generally takes about 10 minutes of surgical time.

Recovery

Progressive normal use of the shoulder begins immediately after surgery. Most patients are able to resume golf and heavier shoulder workouts by approximately 6 to 8 weeks, notwithstanding any additional procedures performed at the same time.

AC Joint Separation (Shoulder Separation / AC Joint Dislocation)

• Grade I: Sprain of the supporting ligaments without tearing.
• Grade II: Partial tearing of the supporting ligaments, resulting in mild elevation of the clavicle.
• Grade III: Complete tearing of the supporting ligaments, resulting in obvious elevation of the clavicle.

Most injuries are initially treated conservatively. If pain persists, reconstructive surgery may be considered after an appropriate period of conservative treatment. The AC joint injection is both a treatment and a diagnostic test. When it completely relieves the pain, it confirms that the AC joint is a primary source of the patient's symptoms.