Subacromial Decompression / Acromioplasty

Why this approach — at MOS

We apply selective criteria for isolated acromioplasty. The evidence that acromioplasty alone provides superior outcomes compared to supervised physical therapy for impingement without a rotator cuff tear is not definitive, and we do not recommend surgery for patients with impingement who have not had an adequate conservative trial. The procedure is most clearly indicated when structural impingement is confirmed, conservative treatment has genuinely failed, and the pain is sourced from the subacromial space (as confirmed by injection response).

When acromioplasty is performed alongside rotator cuff repair, we find it a natural component of the repair — the spur that contributed to the tear is removed, and the repaired tendon has a clear subacromial path for recovery. We do not routinely perform acromioplasty on every rotator cuff repair if no structural spur is present; the procedure is targeted to anatomy.

Who is a candidate?

Indications

• Documented shoulder impingement syndrome with subacromial bone spurs or hooked (Type II/III) acromion on X-ray or MRI
• Persistent pain with overhead activity that has failed 3–6 months of physical therapy, activity modification, and subacromial corticosteroid injection
• Performed concomitantly with rotator cuff repair when acromial spurs are present
• Subacromial bursitis with thickened, impinging bursa not responding to conservative measures

Contraindications

• Impingement symptoms without structural spur — isolated soft-tissue decompression without bone pathology has poor evidence as an isolated procedure
• Active infection
• Rotator cuff tear arthropathy (shoulder replacement is more appropriate)
• Significant glenohumeral arthritis (arthroplasty considerations take precedence)

Conservative Treatment First

The large majority of shoulder impingement cases resolve without surgery. Physical therapy is the cornerstone of conservative treatment — specifically targeting rotator cuff strengthening (infraspinatus, subscapularis), periscapular muscle strengthening (lower trapezius, serratus anterior), and postural correction to optimize the mechanics of arm elevation. Strengthening the muscles that keep the humeral head centered in the socket increases the subacromial space dynamically.

Subacromial corticosteroid injection provides meaningful, lasting relief for many patients with bursitis-dominant impingement and is both therapeutic and diagnostic — if the injection provides complete (if temporary) relief, it confirms the subacromial space is the pain generator and predicts a good response to surgery. Physical therapy begun after injection, when pain is reduced, is often more productive than therapy alone.

Surgery is recommended after 3–6 months of supervised conservative care without adequate relief, particularly when structural impingement (a large spur or Type III acromion) is confirmed. Patients presenting to our Bethesda and Germantown offices can receive a subacromial injection at the time of evaluation and begin a structured therapy program before any surgical decision is made.

The procedure

What Is Subacromial Decompression / Acromioplasty?

Subacromial decompression (acromioplasty) is an arthroscopic procedure that removes bone spurs from the underside of the acromion to create more room for the rotator cuff tendons beneath. It relieves shoulder impingement — pain and pinching with overhead movements — when conservative treatment has not worked.

The subacromial space is the narrow corridor between the top of the humeral head and the underside of the acromion. The rotator cuff tendons, particularly the supraspinatus, pass through this space with every movement of the arm. When bone spurs form on the undersurface of the acromion — from arthritis, acromial morphology (a hooked or curved acromion), or chronic mechanical irritation — the space narrows. Every time the arm is lifted, the tendon is pinched between the spur and the humeral head. This produces the classic pattern of shoulder impingement: pain with reaching overhead, across the body, or behind the back, often with a painful arc between 70–120 degrees of elevation.

Acromioplasty removes these spurs using a motorized burr inserted arthroscopically, flattening the underside of the acromion and restoring adequate space for the rotator cuff to glide freely. The coracoacromial ligament — which can also contribute to impingement — may be partially or fully released at the same time.

Subacromial decompression is frequently performed in conjunction with rotator cuff repair when a rotator cuff tear and acromial spurs coexist — the decompression reduces impingement on the repair and may lower re-impingement risk. As an isolated procedure, it is most appropriate for patients with confirmed structural impingement (documented bone spur, hooked acromion) who have failed conservative management.

What Happens During Subacromial Decompression?

You arrive at the ambulatory surgery center approximately 60–90 minutes before surgery. An interscalene nerve block is placed for post-operative pain control. General anesthesia is administered. You are positioned in the beach chair or lateral decubitus position.

The arthroscope is inserted into the glenohumeral joint through a posterior portal. The joint is inspected for rotator cuff tears, labral pathology, biceps tendon disease, and cartilage status. The arthroscope is then repositioned into the subacromial space through the same portal. The subacromial bursa is visualized and resected with a motorized shaver to allow clear visualization of the acromion undersurface and rotator cuff.

The acromion is inspected directly. Bone spurs on the anterior and inferior acromion are identified. A motorized burr is used to resect the spur and flatten the acromion undersurface. The amount of bone removed is limited to what is necessary to create a flat, smooth surface — approximately 3–7 mm in most cases. The coracoacromial ligament is released from the anterior acromion if it is contributing to impingement.

If a rotator cuff tear is identified, it is repaired at this point before the decompression, or the decompression can be done first — the sequence depends on surgeon preference and the size of the tear.

Portals are closed and the arm is placed in a sling.

Recovery timeline

Frequently Asked Questions

Meet the surgeons

James S. Gardiner, MD

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Christopher S. Raffo, MD

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John J. Christoforetti, MD

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