Distal Clavicle Excision

Why this approach — at MOS

The two technical priorities in distal clavicle excision are: resecting enough bone to eliminate contact (at least 5 mm), and not resecting so much that the superior AC ligaments are compromised (generally no more than 10 mm). An inadequate resection is the most common cause of persistent pain after this procedure. We use direct visualization and bursoscopy to confirm bone-end position before closing.

When the AC joint is being addressed during the same case as a rotator cuff repair, we typically perform the AC excision at the end of the rotator cuff portion to maintain subacromial working space throughout the repair. This sequencing avoids fluid extravasation into the AC joint tissue during repair that would obscure excision quality.

Who is a candidate?

Indications

• AC joint osteoarthritis with pain on cross-body adduction and overhead activity, confirmed on X-ray and/or MRI
• Distal clavicle osteolysis — bone resorption at the clavicle tip in weightlifters or overhead athletes
• AC joint pain from inferior osteophytes causing impingement on the rotator cuff, often performed simultaneously with rotator cuff repair
• Failed conservative management over 3–6 months

Contraindications

• AC joint instability (Grade III–V separation) — excision without stabilization would worsen instability
• Active infection
• Excessive resection (more than 10 mm risks disrupting AC ligaments and causing horizontal instability)
• Patient with isolated pain unrelated to the AC joint after thorough workup

Conservative Treatment First

AC joint arthritis and osteolysis frequently respond to conservative treatment. Activity modification — particularly reducing or eliminating bench pressing, push-ups, and overhead lifting — often provides meaningful relief in weightlifters with osteolysis. Anti-inflammatory medications and a corticosteroid injection directly into the AC joint (a targeted, precise injection separate from subacromial injection) can substantially reduce pain and serve as both a therapeutic and diagnostic tool. If the injection provides complete but temporary relief, it confirms the AC joint is the pain source and surgical excision will likely be effective.

Physical therapy for the surrounding rotator cuff and scapular musculature improves shoulder mechanics and reduces stress on the AC joint. Surgery is recommended when 3–6 months of these measures have not provided adequate lasting relief, and when AC joint pathology has been clearly confirmed as the pain generator. Patients in the Montgomery County area can receive AC joint injections at any of our office locations before deciding on surgery.

The procedure

What Is Distal Clavicle Excision?

Distal clavicle excision (also called the Mumford procedure) removes a small section of the end of the collarbone to eliminate bone-on-bone contact at the AC joint. It relieves pain from AC joint arthritis or osteolysis. The procedure is performed arthroscopically and takes about 20–40 minutes.

The acromioclavicular (AC) joint sits at the top of the shoulder, where the clavicle (collarbone) meets the acromion (part of the shoulder blade). Like other joints, the AC joint can develop arthritis — cartilage wears away, bone spurs form, and the joint becomes painful, particularly with overhead movements and reaching across the body. AC joint osteolysis is a related condition common in weightlifters, where the bone at the tip of the clavicle is slowly resorbed, causing pain and weakness with bench pressing and overhead lifting.

By removing 5–10 mm of the distal end of the clavicle arthroscopically, the surgeon creates a gap between the clavicle and the acromion. The bone surfaces no longer touch, pain from direct bone contact is eliminated, and any impinging bone spurs from the clavicle are removed. Scar tissue fills the gap over time and provides adequate stability — the procedure does not destabilize the AC joint as long as the superior AC ligaments and the CC ligaments are preserved.

Distal clavicle excision is often performed as an isolated procedure for AC joint pathology, but it is frequently combined with rotator cuff repair, subacromial decompression, or other shoulder procedures in patients who have both AC joint pain and other shoulder pathology at the same time.

What Happens During Distal Clavicle Excision?

You arrive at the ambulatory surgery center approximately 60–90 minutes before surgery. General anesthesia is administered with an interscalene nerve block. You are positioned in the beach chair or lateral decubitus position.

The procedure is performed entirely arthroscopically through 2–3 small portals. The arthroscope is inserted into the subacromial space (not the glenohumeral joint for isolated AC excision, though both spaces may be inspected in combined cases). The undersurface of the distal clavicle and acromion are visualized directly. Any inferior osteophytes are removed with a motorized burr. The distal 5–10 mm of the clavicle is then resected using the burr in a controlled, even fashion. The amount resected is measured directly — an inadequate resection leaves persistent bony contact; an excessive resection compromises the superior AC ligaments.

The AC joint capsule above is preserved. Portals are closed and the arm is placed in a sling.

Recovery timeline

Frequently Asked Questions