Shoulder Impingement Treatment
Shoulder impingement syndrome — also called subacromial impingement — is one of the most common causes of shoulder pain, occurring when the rotator cuff tendons and the subacromial bursa are compressed and pinched beneath the acromion (the bony roof of the shoulder) during overhead arm movements. The subacromial space — the narrow gap between the top of the humeral head and the underside of the acromion — is only about one centimeter wide, and when anything reduces that space further (bone spurs, a thickened bursa, a swollen rotator cuff tendon, or a downward-sloping acromion shape), the soft tissues become trapped and irritated with every overhead reach, producing the characteristic arc of pain that worsens progressively over time. Without treatment, chronic impingement leads to bursitis, rotator cuff tendinitis, and eventually partial or complete rotator cuff tears — making early diagnosis and treatment essential for preventing permanent structural damage.
Dr. Jonathan Glashow is a board-certified orthopedic surgeon and Clinical Associate Professor of Orthopedic Surgery at NYU Grossman School of Medicine, with a traveling shoulder fellowship under Dr. Charles Rockwood and Dr. Richard Hawkins and fellowship training in arthroscopic surgery at the Southern California Orthopedic Institute/UCLA. Shoulder impingement is the most frequently diagnosed condition in his shoulder practice, and his treatment approach focuses on identifying the specific cause of the impingement — whether structural (bone spurs, acromion shape), functional (rotator cuff weakness, scapular dyskinesis), or a combination of both — because the most effective treatment targets the cause, not just the symptom. As Chief Medical Officer for the New Jersey Devils and Philadelphia 76ers and a Castle Connolly Top Doctor every year since 2000, he evaluates and treats shoulder impingement at his Upper East Side practice in New York City.
Causes and Contributing Factors
Shoulder impingement develops when the subacromial space is narrowed by structural or functional factors — or both working together.
Structural Causes: Bone spurs (osteophytes) on the underside of the acromion, a hooked or downward-sloping acromion shape, thickening of the coracoacromial ligament, AC joint arthritis with inferior bone spur formation, and calcific deposits within the rotator cuff tendons all physically reduce the available space.
Functional Causes: Weakness in the rotator cuff muscles — particularly the external rotators and the supraspinatus — allows the humeral head to migrate upward during overhead motion, narrowing the subacromial space dynamically. Poor scapular mechanics (scapular dyskinesis), tightness in the posterior capsule, and poor posture contribute to abnormal shoulder mechanics that increase impingement with overhead activity.
Repetitive Overhead Activity: Athletes involved in swimming, tennis, baseball, volleyball, and overhead sports are at elevated risk, as are individuals whose occupations require repetitive reaching, lifting, or working above shoulder height.
Symptoms of Shoulder Impingement
- Pain with overhead reaching, lifting, or raising the arm to the side
- A painful arc — discomfort that occurs between approximately 60 and 120 degrees of arm elevation
- Pain at the front and outside of the shoulder
- Night pain, particularly when lying on the affected side
- Shoulder weakness and difficulty with overhead activities
- Pain that worsens progressively over weeks to months
- A catching or grinding sensation during shoulder movement
Stages of Shoulder Impingement
Shoulder impingement progresses through three recognized stages if left untreated.
Stage I — Inflammation and Swelling: The rotator cuff tendons and bursa become inflamed and swollen from repetitive compression. This stage is most common in patients under 25 and is fully reversible with rest and treatment.
Stage II — Tendinitis and Fibrosis: Repeated episodes of impingement lead to chronic tendinitis, thickening and fibrosis (scarring) of the bursa, and early degenerative changes in the rotator cuff tendons. This stage is most common in patients between 25 and 40.
Stage III — Rotator Cuff Tears and Bone Changes: Chronic, untreated impingement eventually produces partial or complete rotator cuff tears, bone spur formation, and structural changes in the acromion. This stage is most common in patients over 40 and often requires surgical intervention.
Treatment Options
Conservative Treatment: The majority of shoulder impingement cases — particularly Stage I and early Stage II — respond well to non-surgical management. Dr. Glashow’s conservative approach includes activity modification (avoiding the specific overhead movements that provoke impingement), anti-inflammatory medications, corticosteroid injections into the subacromial space to reduce inflammation, and a structured physical therapy program focused on rotator cuff strengthening, scapular stabilization, posterior capsule stretching, and postural correction. Physical therapy is the cornerstone of impingement treatment because it addresses the functional causes that contribute to subacromial narrowing.
Arthroscopic Subacromial Decompression: When conservative treatment has not provided adequate relief after three to six months, or when imaging reveals structural causes such as bone spurs or a hooked acromion that will not respond to rehabilitation alone, Dr. Glashow may recommend arthroscopic surgery. The procedure involves removing the inflamed bursa, shaving the underside of the acromion to increase the subacromial space (acromioplasty), removing bone spurs, and evaluating and repairing any rotator cuff damage found during the procedure. Surgery is performed on an outpatient basis through small keyhole incisions.
Shoulder Impingement Treatment in New York City
If you are experiencing shoulder pain with overhead activity that has been getting worse over time, difficulty sleeping on the affected side, or progressive weakness in your arm, shoulder impingement may be the cause — and early treatment can prevent the condition from progressing to rotator cuff damage. Dr. Glashow offers comprehensive shoulder evaluation with same-day imaging at his Upper East Side practice. Contact our office to schedule your consultation.
Frequently Asked Questions About Shoulder Impingement
What is shoulder impingement?
Shoulder impingement is a condition in which the rotator cuff tendons and the subacromial bursa are repeatedly compressed and pinched beneath the acromion — the bony projection at the top of the shoulder — during overhead arm movements. This compression causes inflammation, pain, and progressive damage to the soft tissues in the subacromial space. Impingement is one of the most common causes of shoulder pain in adults and is particularly prevalent in people who perform repetitive overhead activities.
What is the difference between shoulder impingement and a rotator cuff tear?
Impingement is the mechanical compression of the rotator cuff and bursa beneath the acromion — it describes the process. A rotator cuff tear is structural damage to the tendon itself — a partial or complete tear in the tendon fibers. However, the two conditions are directly related: chronic, untreated impingement is the leading cause of degenerative rotator cuff tears. In early stages, impingement produces inflammation and tendinitis that are fully reversible with treatment. If the impingement continues, the tendon gradually weakens, frays, and eventually tears. This is why treating impingement early — before it damages the rotator cuff — is so important.
How is shoulder impingement diagnosed?
Dr. Glashow diagnoses shoulder impingement through a clinical examination that includes specific provocative tests — such as the Neer test, Hawkins-Kennedy test, and painful arc assessment — that reproduce the impingement by compressing the subacromial space in a controlled manner. X-rays can reveal bone spurs, acromion shape, and AC joint arthritis. An MRI may be ordered to evaluate the condition of the rotator cuff tendons and bursa and determine whether impingement has already caused tendon damage. Same-day imaging is available at his Upper East Side practice.
Can shoulder impingement be treated without surgery?
Yes — the majority of impingement cases respond well to non-surgical treatment. A structured physical therapy program that strengthens the rotator cuff, stabilizes the scapula, stretches the posterior capsule, and corrects postural mechanics is effective for most patients, particularly when combined with anti-inflammatory medications and corticosteroid injections during the acute phase. Surgery is reserved for patients who do not improve with three to six months of dedicated conservative care, or who have structural causes (bone spurs, hooked acromion) that rehabilitation alone cannot address.
What does arthroscopic subacromial decompression involve?
Arthroscopic subacromial decompression is performed through two to three small incisions using a camera and miniature instruments. Dr. Glashow removes the inflamed bursal tissue, shaves the underside of the acromion to create more space for the rotator cuff tendons (acromioplasty), removes any bone spurs, and inspects the rotator cuff for tears — repairing them during the same procedure if found. The surgery typically takes 30 to 60 minutes and is performed on an outpatient basis at Midtown Surgery Center. Most patients are in a sling for a few days and begin physical therapy within the first week.
Can shoulder impingement come back after treatment?
With proper treatment — whether conservative or surgical — most patients achieve lasting relief from shoulder impingement. The key to preventing recurrence is maintaining the rotator cuff strength, scapular stability, and postural habits developed during rehabilitation. Patients who return to repetitive overhead activities without maintaining their conditioning program are at higher risk for recurrence. After arthroscopic decompression, structural causes such as bone spurs are permanently removed, which significantly reduces the likelihood of recurrence from those specific factors.
