Shoulder impingement syndrome causes symptoms and treatment

Have you ever felt an annoying shoulder pain that gets worse when you raise your arm or even while sleeping? You might think it’s just a simple strain, but in some cases, the cause behind this pain is a common condition known as shoulder impingement syndrome.This condition occurs when the tendons of the shoulder become compressed and irritated within the joint, leading to gradual pain that may start mildly and then worsen over time if not properly managed. The problem is that many people ignore the early symptoms, which can eventually lead to complications affecting arm movement and overall quality of daily life.In this Dalyli Medical article, we’ll take you on a simple journey to understand the causes of this syndrome, its symptoms, how it is diagnosed, and the latest treatment methods—whether through exercises, medications, or even surgery—along with important tips to help you prevent it from progressing.

What is shoulder impingement syndrome?

Shoulder impingement syndrome is a common condition that occurs when there is pressure or friction between the tendons and muscles of the shoulder joint and the surrounding bones, especially the acromion bone. This repeated rubbing leads to tendon inflammation, persistent pain, and difficulty moving the arm, particularly when lifting it above shoulder level.

Is shoulder impingement dangerous?

In most cases, shoulder impingement syndrome is not considered a serious condition. However, it can worsen over time if not properly treated, potentially leading to chronic inflammation or even a tear in the shoulder tendons.

Does the pain increase with movement?

Yes. Pain typically worsens with movement, especially when raising the arm overhead or placing it behind the head. This is one of the most characteristic symptoms of the condition.

Are exercises helpful or can they worsen the pain?

Therapeutic exercises are very beneficial in improving the condition and reducing symptoms. However, they must be performed gradually and under the supervision of a specialist, because incorrect exercise techniques may increase friction and worsen the pain.

Does sleeping affect the pain?

Yes. Sleeping on the affected shoulder can increase pain and discomfort. It is recommended to sleep on the back or the unaffected side, and to support the affected arm with a pillow to reduce pressure.

Can shoulder impingement return after treatment?

Yes, shoulder impingement syndrome may recur after treatment if the patient does not maintain proper habits, such as lifting weights incorrectly, poor posture, or returning too quickly to intense physical activity without adequate rehabilitation. Therefore, continuing strengthening and physical therapy exercises is essential for preventing recurrence.

Types of Shoulder Impingement Syndrome

Shoulder impingement syndrome varies in cause, location, and severity, which helps doctors determine the appropriate treatment plan.

1. By cause

1) Primary impingement
Occurs due to structural abnormalities in the bones, such as bone spurs or a narrowed subacromial space, which directly increases friction on the tendons.

2) Secondary impingement
Results from functional problems such as weak shoulder muscles or joint instability. It is more common among athletes.

2. By location

1) Subacromial impingement
The most common type, occurring under the acromion (roof of the shoulder), affecting the rotator cuff tendons and the bursa.

2) Internal impingement
Occurs inside the shoulder joint itself and is often seen in athletes who perform overhead throwing sports like tennis and baseball. The pain is deeper within the joint.

3) Subcoracoid impingement
Less common, it occurs at the front of the shoulder and is usually triggered by movements that bring the arm across the body.

3. By severity (Neer classification)

Stage I:
Mild inflammation and swelling of the tendons, usually responding well to conservative treatment without surgery.

Stage II:
Increased tendon thickening with fibrosis, leading to more persistent and stronger pain.

Stage III:
Partial or complete tendon tear, which may require surgical intervention in some cases.

Causes of Shoulder Impingement Syndrome

Shoulder impingement syndrome occurs when the tendons of the shoulder or the subacromial bursa become compressed or repeatedly rubbed under the upper shoulder bone (the acromion), leading to pain and reduced joint mobility.

1) Repetitive overhead movements

Activities that involve repeatedly lifting the arm above shoulder level—such as swimming, tennis, or weightlifting—can irritate the tendons and surrounding tissues over time, leading to inflammation and pain.

2) Weak or imbalanced shoulder muscles

Especially weakness in the rotator cuff muscles. When these muscles are weak or not well balanced, shoulder stability decreases, which increases friction inside the joint.

3) Poor posture

Long periods of slouching forward, such as sitting at a computer or using a phone for extended time, can alter shoulder mechanics and increase pressure on the tendons.

4) Tendon or bursa inflammation

Chronic inflammation can cause swelling of the tissues inside the joint, reducing the space available for tendon movement and increasing impingement.

5) Bone changes

Such as bone spurs on the acromion. These reduce the space through which the tendons pass, increasing the likelihood of impingement.

6) Injury or sudden strain

Sudden heavy lifting or incorrect movement during sports or physical activity may trigger or worsen the condition.

Symptoms of Shoulder Impingement Syndrome

Symptoms usually develop gradually and worsen with movement, especially when lifting the arm.

1) Shoulder pain

Pain in the front or outer part of the shoulder
Worsens when lifting the arm or moving it backward
May radiate down the arm in some cases

2) Pain during sleep

Worse when lying on the affected shoulder
May cause frequent waking due to discomfort
Increased pain with turning in bed

3) Weakness in arm movement

Difficulty lifting the arm above shoulder level
Feeling of heaviness or weakness
Reduced ability to perform daily activities

4) Clicking or grinding sensation

A feeling or sound of friction during shoulder movement
More noticeable when raising the arm

5) Difficulty with daily activities

Pain while dressing or combing hair
Increased discomfort during overhead activities

6) Gradual stiffness

Reduced shoulder flexibility over time
Increasing difficulty in moving the arm if untreated

Diagnosis of Shoulder Impingement Syndrome

Diagnosis is based on a combination of symptoms, physical examination, and imaging tests to confirm the condition and rule out other problems.

1) Medical history

The doctor usually asks about:

Location and nature of the pain
Whether pain increases when lifting the arm
Pain during sleep
Duration and progression of symptoms

2) Physical examination

Checking shoulder range of motion
Observing pain during arm elevation
Assessing muscle strength
Detecting clicking or friction

3) Special tests

Neer test
Hawkins-Kennedy test

If pain occurs during these tests, it supports the diagnosis of shoulder impingement syndrome.

4) Imaging tests

1) X-ray:
Can show bone spurs or narrowing under the acromion.

2) MRI:
Provides detailed images of the rotator cuff tendons and can detect inflammation or tears.

3) Ultrasound:
Helps assess tendon thickness and inflammation quickly.

Complications of Shoulder Impingement Syndrome

Complications usually occur when the condition is ignored or when harmful habits continue, increasing friction inside the shoulder joint.

⚠️ 1) Chronic tendon inflammation

Long-lasting inflammation
Recurrent pain even at rest
Progressive weakness in shoulder function

⚠️ 2) Rotator cuff tear

Partial or complete tendon tear
Significant weakness in lifting the arm
In advanced cases, surgical intervention may be required

⚠️ 3) Shoulder stiffness (Frozen Shoulder)

Gradual loss of range of motion
Severe difficulty moving the shoulder in all directions
Increasing pain as stiffness progresses

⚠️ 4) Muscle weakness

Results from reduced use of the shoulder due to pain
Weakness in shoulder and arm muscles
Negative impact on daily activities

⚠️ 5) Chronic pain and impact on daily life

Difficulty sleeping and moving the arm
Problems with dressing or performing simple tasks
Psychological impact due to long-term pain

Drug Treatment for Shoulder Impingement Syndrome

Drug treatment aims to reduce pain and inflammation and improve shoulder movement. It should always be combined with physical therapy for best results.

1) Non-steroidal anti-inflammatory drugs (NSAIDs)

Examples:

Ibuprofen
Diclofenac
Naproxen

Role:

Reduce pain
Decrease inflammation around shoulder tendons
Improve mobility

These medications are usually used for short periods under medical supervision, especially in patients with stomach or kidney issues.

2) Simple pain relievers

Example:

Paracetamol

Role:

Pain relief only
Does not treat inflammation
Used in mild cases or alongside other medications

3) Cortisone injections

Injected into the shoulder joint or subacromial space.

Benefits:

Rapid reduction of inflammation
Quick pain relief
Helps start physical therapy

They are not used frequently and must be administered by a specialist.

4) Topical treatments

Example:

Diclofenac gel

Benefit:

Local pain relief in mild cases
Suitable for patients who prefer to avoid oral medications

5) Muscle relaxants (when needed)

Examples:

Tizanidine
Baclofen

Used when:

Muscle spasm is present
Pain is associated with stiffness

Not required in all cases.

⚠️ Important note

Medication alone is not enough because:

It only relieves symptoms
The underlying cause (mechanical impingement) requires physical therapy and correction of shoulder mechanics

Surgical Treatment of Shoulder Impingement Syndrome (Types & Procedures)

Surgery is considered a last option and is recommended only when conservative treatment fails for 3–6 months or in cases of tendon tears or severe narrowing in the shoulder space.