Shoulder impingement is a common shoulder condition that causes shoulder pain. It occurs when the tendons of the rotator cuff or long head of the biceps pass through a narrow space between the acromion (the bony extension of the shoulder blade) and the humerus (upper arm bone) during lifting or reaching above shoulder height. This pinches and irritates the tendons. It can occur due to repetitive overhead activities or following an injury.

Causes of Impingement Syndrome
There are a few factors that can contribute to shoulder impingement developing:

- Poor posture - Having rounded shoulders that are internally rotated puts extra pressure on the rotator cuff tendons as they pass under the acromion.

- Overuse injuries - Repeated overhead activities like swimming, tennis, weightlifting or jobs like painting can lead to overuse of the rotator cuff tendons over time.

- Injuries - Falls on an outstretched arm or trauma directly to the shoulder can cause microscopic tears in the tendons.

- Calcification - Calcium deposits may form in the tendons, especially in older patients. This makes the tendons thickened and less mobile.

- Bone abnormalities - Sometimes the shape of the acromion or spurs on the acromion bone can predispose to impingement by decreasing the space available.

Symptoms of Impingement Syndrome

The main symptoms of shoulder impingement are:

- Gradual onset shoulder pain that worsens with overhead activities and lifting the arm above head height.

- Pain may radiate down the arm.

- Tenderness over the front and side of the shoulder.

- Clicking or catching sensation in the shoulder.

- Weakness or stiffness in the shoulder joint.

- Sleep disturbance due to pain.

Diagnosis of Impingement Syndrome

Doctors can diagnose shoulder impingement based on a physical examination and history of symptoms and activities. Tests that may be used include:

- X-rays - Can rule out injuries and show bone spurs.

- MRI scan - Clearly shows soft tissues like tendons and muscles to check for tears.

- Ultrasound guided injection - Steroid injection into the bursa can help relieve symptoms temporarily to confirm diagnosis.

- Blood tests - Only if infection is suspected.

Treatment for Impingement Syndrome

Conservative treatments are usually tried first and may include:

- Resting the shoulder and avoiding aggravating activities.

- Icing sore areas to reduce inflammation.

- Physiotherapy - Specific stretches and exercises to improve posture, mobility and strengthen muscles.

- Oral anti-inflammatory medications - May provide short term pain relief.

- Steroid injections - Directly into bursa to reduce inflammation.

- Braces or supports - To limit shoulder motion during healing.

If conservative treatments don't work after 3 months, surgery may be considered:

- Arthroscopic surgery - Allows clear visualization inside joint to shave bone spurs/debride inflamed tissues. Has good success rates.

- Open Surgery - Only if substantial tendon or labral tears are present that require repair. Recovery is longer.

Outcomes for Impingement Syndrome

With appropriate non-surgical or surgical management, most patients improve significantly. Prompt treatment and compliance with post-care advice leads to the best outcomes. Recurrence is possible if causative activities aren't modified, especially in occupations with repetitive overhead arm motions. Maintaining good posture and conditioning of shoulder muscles through life helps prevent recurring impingement syndrome.