Shoulder Impingement

Subacromial impingement is the repeated squeezing of the rotator cuff tendons and a small fluid-filled cushion (the bursa) against the bony shelf at the top of the shoulder when the arm is raised. The compression inflames the bursa, which thickens and presses further on the tendons. The pain usually builds gradually over weeks to months of overhead activity rather than starting with a single injury. The anatomy that makes the space tight does not change on its own, but the pain can be managed.

Symptoms usually come on gradually. Common symptoms include:

• Pain on the outside of the shoulder and upper arm, worse reaching overhead or out to the side
• A painful arc, with pain worst through a mid-range of motion around ear height
• Night pain that makes lying on the shoulder uncomfortable
• Weakness or difficulty with overhead tasks such as reaching a shelf or getting dressed
• A catching or pinching feeling at the top of the shoulder

Diagnosis is made from the history and a focused exam, with the pattern of pain during overhead activity and a painful arc being characteristic. X-rays check the shape of the bony shelf and look for a bone spur. An MRI is added when the exam suggests the tendon may be involved or symptoms do not improve as expected.

Most people are treated without surgery:

• Physical therapy to strengthen the rotator cuff and shoulder-blade muscles, the centerpiece of treatment
• Anti-inflammatory medication to settle the inflamed bursa
• Activity changes to reduce overhead lifting while therapy is underway
• A corticosteroid injection into the bursa to allow real progress in therapy

Surgery is considered when pain persists despite a genuine course of therapy and injection and imaging shows a clear structural reason. The procedure shaves the underside of the bony shelf to make more room for the tendons, and if the rotator cuff is torn, repair is added at the same time.

• Shoulder arthroscopyShoulder
• Rotator cuff repairShoulder

For a fuller explanation, including anatomy, diagnosis, and the full range of treatment:

• Shoulder Impingement / Rotator Cuff Tendinitis — AAOS OrthoInfo