April 20, 2024

Understanding Impingement Syndrome: Causes and Treatment.

Impingement syndrome is a common shoulder condition that occurs when soft tissues surrounding the shoulder joint, such as the tendons of the rotator cuff or bursa, get compressed or ‘pinched’ between the head of the humerus (upper arm bone) and the underside of the acromion (part of the shoulder blade). This pinching and inflammation can cause shoulder pain, especially with overhead activities or reaching behind your back.

Causes of Impingement Syndrome

Anatomy and Mechanics
The space available for the rotator cuff tendons to pass under the acromion is only about 1 cm. When the shoulder is raised overhead, this space narrows even further. Repeated overhead motions can cause the tendons to rub against or ‘impinge’ on the underside of the acromion.

Repeated Motions
Jobs or sports that require repetitive overhead motions are a major risk factor for developing impingement syndrome. Common culprits include throwing sports, painting, construction work and swimming. The repeated stress on the rotator cuff tendons from overhead movements can lead to inflammation, swelling and impingement over time.

Postural Issues
Poor posture with rounded shoulders can place the arm in a position more vulnerable to impingement. Spending long hours hunched over a desk or looking down at mobile devices puts the shoulders into protracted, internally rotated positions that narrow the space for the rotator cuff tendons.

Past trauma to the shoulder, such as dislocations, rotator cuff tears or fractures, can alter the mechanics and lead to impingement down the road if not addressed properly. The healing tissues may become swollen or scarred, further reducing space in the shoulder.

Signs and Symptoms of Impingement Syndrome

The main symptom of impingement syndrome is shoulder pain, especially with overhead activities like combing hair, reaching for something high up or throwing. Other common signs and symptoms include:

– Pain deep within the shoulder joint, often felt at the front or side of the shoulder. Common to feel pain with passive raising of the arm.

– Pain that worsens at night or with lying on the involved shoulder.

– Catching, popping or grinding sensation in the shoulder with certain ranges of motion.

– Weakness, stiffness or limited range of motion in the shoulder.

– Pain radiating down the arm with impingement of the rotator cuff tendons or biceps tendon.

– May be difficult or painful to place a coat or shirt on over the head.

– May have difficulty sleeping on the involved side due to pain.

– Tenderness over the front, side or top of the shoulder when pressed.

Diagnosis of Impingement Syndrome

A doctor will first take a complete health history and conduct a physical exam of the shoulder to check range of motion, strength, posture and identify areas of tenderness. Diagnosis is typically made based on reported symptoms and physical exam findings.

To confirm impingement and rule out other potential causes, imaging tests such as x-rays, ultrasound or MRI may be ordered. X-rays can detect arthritis, bone spurs or fractures. Ultrasound provides a less expensive look at soft tissues like tendons. MRI is generally the best imaging choice as it gives a detailed view of muscles, tendons and ligaments without radiation exposure.

An MRI may show findings of tendonitis, bursitis, labral tears, rotator cuff tears or muscle strains—all of which can contribute to impingement. Injections of local anesthetic or corticosteroids into the subacromial space may also help confirm impingement as the pain source if temporary relief is obtained.

Treatment Approaches for Impingement Syndrome

Most cases of impingement syndrome are initially treated nonsurgically with a combination of conservative approaches:

Rest and Activity Modification
The initial treatment is usually rest from aggravating overhead activities along with posture and ergonomic modifications. Continuing to stress the shoulder through impinging movements will prolong recovery.

Physical Therapy Exercises
A physical therapist can create a personalized regimen to decrease inflammation, improve shoulder mobility, strengthen compensatory muscles and progressively regain lost motion. Common exercises include stretching, myofascial release, posture correction and strengthening.

Oral Medications
Over-the-counter anti-inflammatory drugs like ibuprofen (Advil) may help reduce pain and swelling associated with impingement. Prescription-strength anti-inflammatory pills or injectable corticosteroids may be used in more severe cases.

Corticosteroid Injections
Directly injecting corticosteroids into the painful subacromial space aims to reduce inflammation around the shoulder joint tissues. This gives temporary, several week relief to allow resumption of physical therapy exercises.

If symptoms persist or worsen despite 2-3 months of conservative care, additional treatment options include:

Subacromial Injections
For impingement due to inflammation, practitioners may inject local anesthetics, corticosteroids or platelet-rich plasma directly into the subacromial space via ultrasound guidance. This introduces healing substances while minimizing pain temporarily.

When impingement is caused by bone spurs or problems with shoulder structures like the acromion, arthroscopic shoulder surgery may be needed. The goal is to remove tissue compressing soft tissues, repair damaged structures, shave bone spurs or reshape the acromion. Rehabilitation follows surgery.

1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile