Impingement syndrome

Overview

Impingement syndrome, also known as shoulder impingement or subacromial impingement syndrome, is a common condition that causes pain in the shoulder, particularly during overhead movements. It occurs when the tendons of the rotator cuff muscles or the subacromial bursa (a fluid-filled sac) become compressed or irritated as they pass through the narrow space beneath the acromion (part of the shoulder blade). This mechanical irritation can lead to inflammation, swelling, and reduced shoulder mobility over time if not properly managed.

Causes

Impingement syndrome results from narrowing of the subacromial space and repetitive mechanical irritation of the soft tissues. Common causes include:

• Overuse: Repetitive overhead activities such as swimming, tennis, or painting can cause wear and tear on the rotator cuff.

• Shoulder instability or muscle imbalance: Weakness or poor coordination of shoulder muscles can disrupt joint alignment.

• Bone spurs: Extra bone growth on the acromion can further narrow the subacromial space.

• Rotator cuff degeneration: Aging or chronic strain can lead to tendon thickening and inflammation.

• Postural issues: Poor posture, especially forward head and rounded shoulders, can contribute to mechanical impingement.

Symptoms

Symptoms of impingement syndrome can range from mild discomfort to significant pain that affects daily activities. Common symptoms include:

• Shoulder pain: Especially when lifting the arm, reaching overhead, or performing repetitive motions.

• Pain at night: Discomfort that worsens when lying on the affected side.

• Weakness: Reduced strength in the shoulder or arm, particularly during elevation or rotation.

• Limited range of motion: Difficulty raising the arm or performing certain movements.

• Clicking or popping: Sensation of catching or crepitus during shoulder movement in some cases.

Diagnosis

Diagnosis of impingement syndrome involves a combination of clinical evaluation and imaging studies:

• Physical examination: Special tests such as Neer’s sign, Hawkins-Kennedy test, and painful arc test help reproduce symptoms.

• Medical history: Assessment of activity level, occupation, and prior shoulder injuries or surgeries.

• X-rays: Used to identify bony abnormalities such as acromial spurs or narrowing of the subacromial space.

• MRI or ultrasound: Helps evaluate the condition of the rotator cuff tendons and detect inflammation or tears.

Treatment

Treatment for impingement syndrome typically begins with conservative, non-surgical options aimed at reducing inflammation and restoring shoulder function:

• Rest and activity modification: Avoid overhead or aggravating movements.

• Physical therapy: Strengthening and stretching exercises to improve rotator cuff function and shoulder mechanics.

• NSAIDs: Non-steroidal anti-inflammatory drugs to reduce pain and inflammation.

• Corticosteroid injections: May be used in cases of persistent inflammation and pain.

• Surgical intervention: In cases unresponsive to conservative treatment, procedures such as subacromial decompression or rotator cuff repair may be recommended.

Prognosis

The prognosis for impingement syndrome is generally good with early diagnosis and appropriate treatment. Most patients experience significant improvement with physical therapy and lifestyle changes. Full recovery can take several weeks to months, depending on severity and compliance with rehabilitation. If left untreated, impingement can lead to chronic pain, tendon tears, or long-term shoulder dysfunction. Surgical outcomes are typically favorable when performed for properly selected cases.