- Type
- Arthroscopic resection
- Anaesthesia
- General + interscalene block
- Day surgery
- Yes
- Sling
- 2 weeks
- Return to driving
- 2 weeks
- Return to sport
- 8–12 weeks
What it is.
AC joint excision — historically known as the Mumford procedure or distal clavicle excision — is an arthroscopic resection of the arthritic acromioclavicular joint. A small amount of bone (typically 5–10 mm) is removed from the lateral end of the clavicle, eliminating the painful bone-on-bone contact at the AC joint while preserving the surrounding ligaments.
When it is offered.
The procedure is offered for:
- AC joint osteoarthritis — symptomatic and confirmed on imaging.
- Distal clavicle osteolysis — the bone-stress condition often seen in heavy bench-pressers, in which the distal clavicle becomes painful and bony reabsorption is seen on imaging.
In both groups, surgery is considered after a structured trial of non-operative treatment — activity modification, anti-inflammatories and a well-placed image-guided AC joint injection. A positive response to the injection is one of the strongest predictors of a successful surgical outcome.
How it is performed.
Performed arthroscopically under general anaesthesia with a regional block, as day surgery. Standard arthroscopic portals are used. The AC joint is approached either directly (through a specific AC portal) or indirectly through the subacromial space. The arthritic distal 5–10 mm of clavicle is carefully resected with a high-speed burr, preserving the coracoclavicular ligaments and the joint capsule. The amount of bone removed is calibrated to the specific patient's anatomy. Closure with steri-strips.
Recovery.
Weeks 1–2
- Sling for 2 weeks for comfort and to protect the early healing tissue.
- Pendulum and gentle passive range of motion from day 1.
- Return to a desk job within 1–2 weeks.
Week 2–6
- Sling discontinued at 2 weeks; active range progresses.
- Strengthening commences.
- Return to manual work at 4 weeks.
Month 2–3
- Return to non-contact sport at 8 weeks.
- Return to contact sport and heavy bench-press at 12 weeks.
Recovery guidance
Your physiotherapist receives specific post-operative instructions on the day of surgery. View the recovery roadmap for the full rehabilitation journey, or visit For Physiotherapists for protocol requests.
Frequently asked questions.
Will my bench press come back?
Yes — once the procedure has settled and strengthening is complete (usually 12 weeks). The procedure does not affect the strength or position of the clavicle.
Is it the same as AC joint reconstruction?
No. AC joint reconstruction is for instability (separated AC joint); AC joint excision is for arthritis (painful AC joint). They address different problems.
Will my shoulder destabilise?
No. The coracoclavicular ligaments are preserved; only a small amount of bone from the distal clavicle is removed. The shoulder is mechanically stable after the procedure.
How long am I in the sling?
Two weeks — for comfort and to protect the early healing tissue. Pendulum and gentle range of motion start from day 1 underneath the sling.
How will I know it has worked?
Pain relief is typically rapid — within days of surgery. The most predictive pre-operative test is a positive response to a diagnostic image-guided AC joint injection.
Will I have a scar?
Two or three small 5 mm arthroscopic portal scars only.
References.
- Mumford EB. Acromioclavicular dislocation. J Bone Joint Surg Am. 1941;23:799–802.
- Auge WK 2nd, Fischer RA. Arthroscopic distal clavicle resection for isolated atraumatic osteolysis. Am J Sports Med. 1998;26(2):189–192.