Overview
Between the top of the humerus and the acromion, the bony roof of the shoulder, is a space about a centimeter high through which the rotator cuff tendons and the subacromial bursa pass every time the arm is raised. Impingement is what happens when that space narrows: the tendons and bursa are pinched against the acromion, the bursa swells, and the swelling makes the space smaller still. It is the most common cause of shoulder pain in adults and, in most cases, a problem of mechanics rather than structure.
What decides treatment is whether the cuff tendon is intact. Impingement with an intact cuff is treated by restoring the mechanics that keep the ball centered in the socket, and it responds well. When the pinching has worn a partial tear into the tendon, or when the space is narrowed by bone that will not change with exercise, surgery has a role.
Common Symptoms
- Pain on the front and outer side of the shoulder with reaching overhead, behind the back, or across the body to fasten a seat belt
- A painful arc: the shoulder hurts most as the arm passes through the middle of its range, roughly 60 to 120 degrees, and is more comfortable above and below
- Night pain, especially lying on the affected side
- Full strength when tested, even though the movement hurts
Pain with a strong arm is impingement; pain with a weak arm is more likely a rotator cuff tear, and the exam distinguishes them. A shoulder that hurts and cannot be moved passively is frozen shoulder. Pain at the very front with palm-up lifting points to biceps tendinitis, which often coexists.
Causes & Risk Factors
Most impingement is secondary, meaning the space is narrowed by the way the shoulder is used rather than by its shape. A weak or fatigued rotator cuff lets the ball ride upward when the arm is raised; a shoulder blade that tilts forward with rounded posture or weak lower-trapezius and serratus muscles lowers the acromion toward it; a tight posterior capsule pushes the ball up and forward. Repetitive overhead activity is the trigger: swimming, tennis, volleyball, baseball, and painting, electrical and construction work. Over 50, a hooked acromion, a spur on its underside, AC joint arthritis or calcium in the tendon can narrow the space structurally and reduce the chance that exercise alone will fix it.
How It Is Diagnosed
Dr. O'Donnell reproduces the pinch. The Neer test raises the arm forward with the shoulder blade held down; the Hawkins-Kennedy test brings the arm to 90 degrees and rotates it inward; both drive the tendon under the acromion and are positive when they reproduce the patient's pain. He watches for a painful arc, then tests each cuff tendon for strength, since weakness on the empty-can or external rotation test changes the diagnosis from impingement to tear. The scapular assist test shows whether shoulder-blade mechanics are the cause.
X-rays are taken at the first visit to look at the shape of the acromion, spurs, calcific deposits in the tendon and AC joint arthritis, the structural narrowing that exercise cannot change. Ultrasound in the office shows the swollen bursa and the tendon and guides an injection precisely into the bursa. MRI is ordered when weakness suggests a tear, when symptoms have not improved after six to eight weeks of proper treatment, or before any surgery, because a partial-thickness tear found on MRI changes the operation. Visiting patients can upload existing images through mymedicalimages.com.
Treatment Options
Non-operative care
Impingement with an intact cuff is treated without surgery, and the large majority of patients recover fully. The program is Dr. O'Donnell's conservative protocol for rotator cuff tendinitis and impingement, run over about twelve weeks and laid out in the table below: two weeks of pain control and motion, four weeks of cuff and shoulder-blade strengthening, then six weeks of progression back to overhead work and sport. When pain is too severe to exercise, or has not eased by the second or third week, an ultrasound-guided corticosteroid injection into the subacromial bursa reduces the inflammation enough for exercise to continue; one injection is usually enough, and repeated injections are avoided because they weaken tendon. Most patients are substantially better by six weeks and back to full activity by twelve.
Arthroscopic subacromial decompression
Surgery is offered when a properly completed three- to six-month program, including an injection, has not resolved the pain, particularly when the X-ray shows a hooked acromion or a spur physically narrowing the space. Arthroscopic subacromial decompression removes the inflamed bursa and shaves the spur from the underside of the acromion through small portals at Bayside Surgery Center. Because no tendon is repaired, recovery is quick: the sling comes off within days, full motion is expected by four weeks and sport by eight to twelve. If a partial-thickness tear involving more than about half the tendon is found at surgery, it is repaired at the same sitting as an arthroscopic rotator cuff repair, and recovery follows the slower cuff-repair timeline, which is why that possibility is discussed before every decompression.
Recovery & What to Expect
For most patients the recovery is the non-operative program itself. Progression is criteria-based, and patients who plateau at any phase are re-examined rather than pushed on.
| Phase | Timing | What happens |
|---|---|---|
| Pain control and motion | Weeks 0–2 | Painful overhead and repetitive reaching paused. Pendulums and active-assisted motion, posture and scapular setting, posterior capsule stretch, ice after activity, sub-maximal cuff isometrics. |
| Strengthening | Weeks 2–6 | Full active motion restored. Band external and internal rotation and scaption in pain-free ranges; rows, lower-trapezius and serratus work; rhythmic stabilization. |
| Return to activity | Weeks 6–12 | Progressive resistance and endurance; overhead and sport-specific progression; interval throwing or serving program as indicated. Discharge on symmetric strength and painless overhead function. |
| After decompression | Weeks 0–12 | Sling for comfort only, off within the first week; full active motion by weeks 2–4; cuff and periscapular strengthening weeks 4–8 to 80% of the other side; full work and sport weeks 8–12. |
Desk work continues throughout non-operative care and resumes within a few days of decompression; driving is possible within a week of surgery; overhead sport returns at 8 to 12 weeks on either path. Both protocols are available as PDFs: rotator cuff tendinitis and impingement, conservative management and shoulder arthroscopy with subacromial decompression.
Frequently Asked Questions
Can shoulder impingement go away on its own?
It often improves when the activity that provoked it stops, but it tends to return when the activity does, because the underlying cuff weakness and shoulder-blade mechanics have not changed. A 6 to 12 week program that strengthens the cuff and retrains the blade fixes the cause and is the treatment for the large majority of patients.
How do I know if it is impingement or a rotator cuff tear?
Both hurt with overhead reaching and at night. The difference is strength: with impingement the arm tests strong even though the movement hurts, while a tear produces weakness on specific tests. Dr. O'Donnell separates them on exam and orders an MRI when there is weakness or pain has not improved after 6 to 8 weeks. See rotator cuff tear.
Should I get a cortisone injection for shoulder bursitis?
If pain is preventing the exercise program or has not eased after 2 to 3 weeks of it, yes. An ultrasound-guided injection into the subacromial bursa usually settles the pain within days and lets the strengthening proceed. One injection is typical; repeated injections are avoided because corticosteroid weakens tendon over time.
When is surgery needed for shoulder impingement?
When a properly completed program of therapy and an injection has not resolved the pain after 3 to 6 months, particularly if the X-ray shows a hooked acromion or a spur narrowing the space. Arthroscopic subacromial decompression removes the bursa and spur through small portals, and most patients are back to sport at 8 to 12 weeks.
Can I keep swimming or lifting with shoulder impingement?
Pause the movements that reproduce the pain, usually overhead pressing, freestyle and butterfly, wide-grip pulls and dips, for the first 2 to 6 weeks. Lower-body training, rowing with the elbows kept low, and kicking sets can continue. Overhead work is reintroduced gradually from week 6 as strength and mechanics return.
This page is for general education and is not a substitute for a medical evaluation. Treatment recommendations depend on your individual diagnosis and goals. Kevin O'Donnell, MD sees patients from Coral Gables, Miami, Brickell, Pinecrest and Coconut Grove at 475 Biltmore Way, and out-of-town patients by telemedicine.