Subacromial [sub-ah-kro-mee-al] decompression, a surgery used to treat shoulder impingement syndrome, can be performed either arthroscopically or through an open incision.

Arthroscopic and open decompression surgeries have similar results,4 reducing shoulder impingement pain in 77% to 90% of patients.5 Which method is used depends on the patient’s circumstances and the surgeon’s preferences.

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Arthroscopic Surgery

During arthroscopic surgery, 2 or 3 small incisions (about 5mm each) are made around the shoulder. A small camera called an arthroscope is inserted through one of the incisions. The arthroscope allows the surgeon to inspect the shoulder joint and biceps and rotator cuff tendons for damage, which can go unseen in an open procedure or an MRI scan.6

See Rotator Cuff Injuries: Diagnosis

Doctors usually recommend arthroscopic surgery for active, young people with moderate shoulder impingement who want to return to sports and/or daily activity.3 Moderate shoulder impingement (sometimes called stage II impingement) is characterized by pain and other symptoms that interfere with daily life.7 It often affects people between the ages of 25 to 40.

See Understanding Different Types of Shoulder Pain

Arthroscopy may also be used to treat older people who have tried nonsurgical treatment without success.3

When arthroscopic subacromial decompression is not advised
An arthroscopic procedure is usually not recommended if the patient has:

  • Preexisting shoulder stiffness.8
  • A large rotator cuff tear that needs to be repaired or cannot be repaired.8 Patients with large rotator cuff tears may be better treated with open surgery.9
  • A flat rather than curved- or hook-shaped acromion.4,10 For people who have flat acromions, tissue inflammation—such as rotator cuff tendonitis and shoulder bursitis—is the cause, not the result, of shoulder impingement.

See Rotator Cuff Injuries

A flat acromion is considered normal, and impingement symptoms are less common and less severe in people with flat acromions. In contrast, a “hooked” or “curved” acromion reduces the size of the subacromial space, putting a person at greater risk for shoulder impingement.

Arthroscopic subacromial decompression is usually an outpatient procedure, which means the patient does not stay the night at the hospital following the procedure.

Open Surgery

An open surgery procedure requires a single, large incision about 4 to 6 cm.11 Open surgery may be necessary if a patient has a large rotator cuff tear. Some surgeons prefer open surgery because it gives them better access to the area being operated on.

See How Do Rotator Cuff Injuries Occur?

Open surgery means a larger incision, and thus an increased risk of infection for the patient compared with arthroscopy. Some patients may be admitted to the hospital for 1 or 2 nights for post-surgical recovery.


  1. Khan Y, Nagy MT, Malal J, Waseem M. The Painful Shoulder: Shoulder Impingement Syndrome. The Open Orthopaedics Journal. 2013; 7: 347-351.
  2. Dopirak R, Ryu RK. Management of the failed arthroscopic subacromial decompression: causation and treatment. Sports Med Arthrosc. 2010;18(3):207-12.
  3. Arthroscopic Shoulder Decompression. Cleveland Clinic website. Accessed September 14, 2016.

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