Distal clavicle resection is a surgical procedure that removes a small portion of bone from the outer end of the collarbone, where it meets the shoulder blade at the acromioclavicular (AC) joint. The amount removed is typically between 2.5 and 8 millimeters. By creating a small gap between the bones, the procedure eliminates the painful bone-on-bone contact that causes chronic shoulder pain. It’s sometimes called the Mumford procedure, after the surgeon who originally described it.
Why the Procedure Is Done
The most common reason for distal clavicle resection is arthritis of the AC joint, the small joint at the top of your shoulder where the collarbone meets a bony projection of the shoulder blade. Over time, the cartilage cushioning that joint wears down, and the exposed bone surfaces grind against each other with every arm movement. This is especially painful when reaching across the body or lifting overhead.
Another frequent indication is distal clavicle osteolysis, sometimes called “weightlifter’s shoulder.” This condition occurs when repetitive stress from overhead movements or heavy pressing causes tiny fractures in the end of the collarbone. Instead of healing normally, the bone gradually breaks down and resorbs, creating pain and inflammation. It’s most common in weightlifters and athletes who perform a lot of overhead work. Surgery is typically recommended only after rest, activity modification, and anti-inflammatory treatments have failed to resolve the pain. For athletes who can’t step away from their sport long enough for conservative treatment to work, surgery often becomes the practical choice.
Distal clavicle resection is also used after certain collarbone fractures that damage the AC joint, and sometimes as part of a larger procedure to address shoulder impingement.
Arthroscopic vs. Open Technique
Surgeons can perform this procedure two ways: through small incisions using a camera (arthroscopic) or through a larger, traditional incision (open). Both approaches achieve the same goal of removing the end of the collarbone, but there are meaningful differences in recovery.
Arthroscopic distal clavicle resection produces more “good” or “excellent” outcomes compared with the open procedure, with success rates exceeding 90%. The arthroscopic approach also allows a faster return to physical activity. One advantage of the arthroscopic route is that the surgeon can inspect the rest of the shoulder joint at the same time, catching problems like labral tears or rotator cuff damage that might otherwise go undiagnosed. The open technique is still used in certain situations, particularly when the surgeon needs to address more complex AC joint instability or when the procedure is combined with other open repairs.
How Much Bone Is Removed
Getting the resection amount right is one of the most important technical details. Too little bone removed and the surfaces may still rub together, leaving you with persistent pain. Too much and the joint becomes unstable because the ligaments anchoring the collarbone lose their attachment points.
Biomechanical research suggests that removing as little as 2.5 to 5 millimeters can eliminate bone contact, though the surgeon needs to take slightly more from the back and bottom of the joint where contact tends to persist. The general upper limit is 8 millimeters. Going beyond that risks destabilizing the joint, which can create a whole new set of problems.
What Recovery Looks Like
Recovery timelines depend heavily on whether the surgery was done arthroscopically or through an open incision, and whether any other shoulder work was done at the same time.
After an isolated arthroscopic procedure, you’ll wear a sling mostly for comfort and can typically remove it the same night. Physical therapy begins around two weeks after surgery, and most people return to full activity by six weeks. Open surgery requires a longer runway: the sling stays on for about three weeks (day and night), physical therapy still starts at two weeks when sutures come out, but full return to unrestricted activity takes closer to three months.
Weight room activities are phased in gradually starting around four weeks post-surgery, based on your tolerance. Exercises that load the AC joint heavily, like bench press, are among the last to return. Expect up to four months before you’re back to your previous performance level on those lifts. Everyday tasks like reaching into a cabinet or carrying groceries come back much sooner.
Success Rates and Patient Satisfaction
In a prospective study of 131 consecutive patients who had arthroscopic distal clavicle resection (many combined with subacromial decompression), 82% reported being satisfied or very satisfied with the outcome at two-year follow-up. Another 12% were almost satisfied. Only 6% were not satisfied. Shoulder function scores improved significantly across the group, with meaningful gains in both pain relief and range of motion.
What Can Go Wrong
The most common reason the surgery fails is persistent pain, and several things can cause it. If too little bone was removed, the joint surfaces may still contact each other. If too much was removed, the remaining joint can become unstable and painful in a different way. Other potential complications include postoperative stiffness, infection, and heterotopic ossification, which is when new bone forms in the gap that was created. In rare cases, the bone can actually grow back across the gap entirely.
One easily overlooked cause of continued pain after surgery is untreated shoulder pathology that was present before the procedure. If a rotator cuff tear or labral tear was contributing to the original symptoms and wasn’t addressed, removing the end of the collarbone won’t fully resolve the pain. This is one reason arthroscopic surgery has an advantage: the surgeon can identify and treat these problems during the same operation.