Shoulder Impingement Syndrome - Symptoms and Treatment

Shoulder impingement is a prevalent cause of pain in the shoulder. It affects the shoulder muscles and tendons, which provide a great range of motion to the arm. Impingement syndrome occurs due to constant rubbing of the tendon and adjacent shoulder bones as the space between them narrows. It can be treated with conservative remedies and by avoiding activities that can cause more pain in the shoulder. 

Impingement in a shoulder hinders the daily life activities of an individual. Normal arm movements such as lifting a bag, extending arms above the head, or even putting on a coat might cause difficulty and pain. Sometimes, the pain is so unbearable that it can affect the patient's sleep cycle as well.

Symptoms of the shoulder impingement syndrome include: 

1. Weakness or stiffness in the shoulder and/or arm
2. Decreased range of motion and strength
3. Pain when reaching into a back pocket or zipping up a zipper
4. Pain that shifts from the front of the shoulder to the side of the arm
5. Difficulty in lying down on the affected side
6. Pain while sleeping at night

Before delving into the causes, it is necessary to understand the anatomic structures involved in the shoulder impingement syndrome. 

1. Rotator Cuff: It is a group of four muscles that emerges from the shoulder blade and attaches as a ‘cuff’ of the tendon onto the humerus (arm bone). It helps in raising and rotating the arm.  
2. Acromion: It is located on the outer edge of the shoulder blade. Impingement occurs when the tendon rubs against the acromion because of space narrowing between them. The space can reduce due to swelling or bone spurs (bony growths near the joint). 
3. Bursa: It is a tiny sac of fluid between the tendon and muscles that gives a slippery motion to the bones and tendons and reduces friction between them.

Other Causes: 

1. Overuse of the rotator cuff tendon due to repetitive overhead activity
2. Inflammation of the bursa due to shoulder injury or overuse
3. The acromion is not flat but curved or hooked by birth 
4. Development of bone spurs with age

Shoulder impingement syndrome is most common in people who play sports, including:-

1. Basketball
2. Volleyball
3. Swimming
4. Handball

People whose work requires repetitive overhead activities are also exposed to the risk of shoulder impingement syndrome. Some of these occupations are:-

1. Painting 
2. Hairdressing
3. Carpentry
4. Construction 

Other factors leading to the impingement syndrome include:-

1. Lifting heavy loads
2. Age-related wear and tear of the tissue
3. Side effects of consuming fluoroquinolone antibiotics (levofloxacin, ciprofloxacin, moxifloxacin, etc.)

The healthcare providers will ask for the patient’s medical history during the diagnosis. The patient may be asked questions regarding previous injuries, exercising habits, overhead activities, and the onset of shoulder pain to understand the cause of the problem and when it began. They also ask if the patient has tried any conservative treatments to relieve the pain. 

The patient undergoes a physical examination, during which the healthcare providers will check the arm’s range of motion. Diagnosis may also include strength testing of the neck and the shoulder.

The health care providers may require an X-ray of the patient's shoulder to rule out arthritis or check the possibility of rotator cuff injury. Bone spurs or any other abnormalities in the normal outline of the bone can also be seen in an X-ray. If the problem is not identified in the X-ray, the patient may need an MRI or ultrasound to detect any tear in the rotator cuff or inflammation in the bursa.

Shoulder impingement can be treated through rehabilitation exercises and anti-inflammatory drugs. Although depending on the severity of the injury, the patient may require surgery. The various types of treatment for shoulder impingement are as follows: 

1. Physical Therapy
   1. At first, the doctor or physiotherapist suggests stretching exercises to improve the range of motion. 
   2. Once the pain reduces, the patient can do exercises (as suggested by the doctor) that strengthen the rotator cuff to improve muscle strength. 
2. Medication: Medicines combined with physical therapy can maximise the treatment effect on an individual. Taking these anti-inflammatory medicines can help in reducing pain and swelling in the shoulders. If the patient doesn’t feel any improvement in the pain, the doctor may suggest a cortisone injection for symptom relief. The most common medicines given to the patient for the treatment of impingement syndrome are: 
   1. Aspirin
   2. Naproxen
   3. Ibuprofen
3. Surgery: Surgery is advised if the symptoms don’t improve through non-surgical methods.
   1. Arthroscopic shoulder decompression is one method to remove part of the acromion to make more space for the rotator cuff. It is performed to widen the space around your rotator cuff. It is a minimally invasive technique that will require small incisions in the shoulder. In severe cases, open surgery may also be suggested. 
   2. Arthroscopic surgery allows the rotator cuff to move freely without causing friction with the other bones. Other problems, such as arthritis in the shoulder or a tear in the rotator cuff, may also require surgical methods for treatment. 

When shoulder impingement remains untreated, it can worsen the symptoms and lead to: 

1. Frozen shoulder
2. Intense pain
3. Rotator cuff tear

If the patient continues the activities that caused shoulder impingement in the first place, he/she may experience inflammation in the tendons (tendonitis) or bursa (bursitis). Inflammation will narrow the space between the rotator cuff and the tendon leading to intense pain. The movement of the shoulder may freeze (causing a frozen shoulder) if there is no space left. 

If an injury in the tendons remains undiagnosed, it can cause thinning of the tendons, and they may even tear.