Shoulder pain

Painful shoulder conditions that limit movement are common, and are caused by problems with the shoulder joint and its surrounding structures. The shoulder is more prone to injuries than other joints because of its wide range of movement.

Common causes of shoulder pain

There are several conditions that cause pain and limit movement of the shoulder joint, including the following.

Rotator cuff disorders

The rotator cuff is a group of muscles and tendons that help to move the shoulder and hold the joint in place. Rotator cuff disorders result from inflammation or damage to the rotator cuff muscles or tendons, or inflammation of the subacromial bursa (the fluid-filled pad that sits under the highest part of the shoulder) - called subacromial bursitis.

The inflammation can be caused by:

  • general wear and tear that occurs with age;
  • activities that require constant or repetitive shoulder motion (especially above shoulder level, such as swimming or painting);
  • heavy lifting; or
  • trauma.

Serious rotator cuff injury and untreated inflammation of the tendons can cause the rotator cuff to tear.

The pain associated with rotator cuff problems is normally felt at the front or on the outside of the shoulder, particularly when you raise your arm or lift something above your head. You may also notice the pain more when lying in bed, particularly when lying on the affected side.

Severe injuries can cause weakness of the shoulder muscles, restricted shoulder movement and continuous pain.

Rotator cuff tears

Your rotator cuff is a group of muscles and tendons that hold the shoulder joint in place and help move the shoulder. The 4 muscles (and their tendons) that make up the rotator cuff include:

  • the supraspinatus;
  • the infraspinatus;
  • the subscapularis; and
  • the teres minor.

rotator cuff injury

It is usually the rotator cuff tendons (the thick bands of tissue that connect the muscles to the bones) that tear, but sometimes the tear occurs in the muscle. The most common site of a tear is in the supraspinatus tendon. Severe injuries can cause several of the tendons and muscles to tear. There are special movement tests that your doctor can use to help determine which of the muscles or tendons has been torn.

Frozen shoulder

Frozen shoulder, also known as adhesive capsulitis, is characterised by progressive pain and stiffness in the shoulder. The pain is felt deep in the shoulder joint and may be worse at night. The pain can be felt with movement in any direction, and stiffness and loss of shoulder movement develop.

The exact cause of this condition is not known, but it sometimes develops following other shoulder injuries or shoulder surgery. It is thought that resting a painful, injured shoulder for too long can cause the shoulder muscles and connective structures to stiffen up. Frozen shoulder can also develop spontaneously, and people with thyroid problems or diabetes seem to be at increased risk.

Most people with frozen shoulder tend to improve within 2 years, with or without treatment, but not all will regain full range of movement. Improvement is usually gradual.

Dislocated shoulder and shoulder instability

Shoulder dislocation occurs when the ball-shaped head of your upper arm bone (humerus) comes out of the shoulder socket. It may be caused by a fall, a sporting injury, or trauma, and is an extremely painful condition.

A dislocated shoulder is visibly deformed or out of place, and there may be swelling or bruising around the joint. Shoulder movement is severely restricted in people with a dislocated shoulder.

Doctors can usually put the shoulder bones back into place using gentle manoeuvres. Pain relief and sedation are usually given beforehand.

Following a dislocation, the shoulder joint sometimes becomes unstable and susceptible to repeated dislocations. This condition is known as shoulder instability, and causes pain and unsteadiness when you raise your arm or move it away from your body. Your shoulder may feel as if it is slipping out of place when you lift your arm over your head.

SLAP (superior labrum anterior posterior) tear

The socket part of the shoulder joint has a ring of tissue around it that deepens the socket, making the joint more stable. This tissue is called the labrum. When the top part of the labrum is injured or torn, it is known as a SLAP tear. SLAP tears are usually the result of an injury such as a fall onto your shoulder or outstretched arm, although they may also arise from repeated lifting or other overhead activities.

Symptoms of a SLAP tear can include pain on throwing or lifting your arm overhead, popping or clicking in the shoulder, a feeling of weakness or instability and a general shoulder ache.

Other causes

Arthritis causes progressive joint pain, tenderness, swelling and stiffness. Both rheumatoid arthritis and osteoarthritis can affect the shoulder joint.

Sometimes shoulder pain is actually due to problems in your neck or a mixture of several different problems. Rarely, shoulder pain may be caused by infection, problems with the nerves, or a tumour.

It is also possible to feel pain in the shoulder that actually relates to pain in another area of the body - this is known as referred pain.

Diagnosis

Doctors can often work out the cause of shoulder pain based on the symptoms and physical examination. Where the pain is felt, both at rest and when moving the shoulder, is a clue to the cause of the shoulder pain.

Part of the physical examination involves testing shoulder strength and the range of movement in the shoulder joint, as well as testing for signs of shoulder impingement.

When it’s thought that pain may be limiting the range of motion of the shoulder joint (rather than weakness), an injection of local anaesthetic into the shoulder may be recommended. Once the pain is relieved, shoulder movement and strength can be tested to help to confirm the diagnosis.

Sometimes X-rays, or other scans such as an MRI or ultrasound, or an arthroscopy may be recommended. During an arthroscopy, your doctor can look inside the shoulder joint using a small telescopic instrument that has a camera on the end.

Treatment

In addition to relieving pain, treatment is aimed at restoring mobility in your shoulder joint. The choice of treatment depends on the shoulder problem.

Your doctor will discuss the risks and benefits of the various treatment options for shoulder pain, and which treatment(s) would be most suitable for you. The timing of various treatments will also depend on your diagnosis.

Pain relief

Pain relievers are often used as an initial treatment for shoulder pain. Paracetamol and non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen and naproxen are often recommended.

Another simple way of easing shoulder pain is by applying a cold pack to your shoulder. Cold packs can reduce inflammation, and are most helpful when applied for the first few days following a shoulder injury. After that, you can switch to using a heat pack; intermittent applications of heat can help relax the shoulder muscles.

Rest

You should also rest the shoulder for a couple of days after most injuries. If you have dislocated your shoulder, you may need to rest your arm in a sling or splint for several weeks after the joint has been manipulated back into place.

However, with most shoulder problems it isn't a good idea to rest for too long, because it can cause the shoulder muscles and connective structures to stiffen up. So, while you should avoid or alter any activities that aggravate your symptoms and avoid strenuous activities and lifting heavy objects, you should still move your shoulder to help make sure that you regain full use of the joint.

By returning to your normal activities as soon as possible (within the limits of disability and pain), you can help prevent your shoulder joint from stiffening up.

Physiotherapy

Physiotherapy can help improve shoulder strength and flexibility as well as relieve the pain associated with most shoulder problems. Physiotherapists use a variety of different therapies, including:

Taping the joint can also help stabilise it and reduce pain during activities.

Physiotherapists can also teach special rehabilitation exercises to stretch and strengthen the rotator cuff muscles of the shoulder. Exercises that improve your shoulder's range of movement help reduce the stiffness that occurs after a period of immobility. Range of motion exercises may be followed by resistance exercises and weight training to strengthen the muscles.

Steroid injections

Depending on the cause of your shoulder problem, corticosteroid injections may be given to relieve the pain in the short term. The corticosteroid, which is often mixed with a local anaesthetic, reduces inflammation and allows you to move the shoulder more comfortably.

Surgery

Some people with shoulder problems will need to be treated with surgery. People with shoulder instability or rotator cuff problems that are not responding to less invasive treatments may benefit from an operation, and shoulder joint replacement may be considered for people with arthritis.

There are also some conditions that need to be treated initially with surgery, including some rotator cuff tears and dislocated shoulders that cannot be reduced (put back in) with simple manual manoeuvres. Young people who have had a dislocated shoulder may need surgery to prevent recurrent dislocations.

Arthroscopic surgery (surgery performed with a special tubular instrument with a camera on the end that is inserted through an incision in the shoulder joint) may be tried for frozen shoulder, rotator cuff tears or SLAP tears of the shoulder.

Other treatments

Acupuncture may help with short-term pain relief in people with rotator cuff disease.

Occasionally, frozen shoulder is treated with what's known as manipulation under anaesthesia. In this therapy, your shoulder is gently moved while you are under a general anaesthetic to help improve its range of motion. Muscle relaxants are also given during this procedure.

Arthrographic distension (also called hydrodilation) is a procedure that may be used in the treatment of frozen shoulder. It involves injecting local anaesthetic, corticosteroid and saline into the shoulder joint, done under radiological guidance. It may help relieve pain and improve function and range of motion, but there is a lack of evidence showing it is more effective than other treatments.

References

1. Limb conditions (published March 2017). In: eTG complete. Melbourne: Therapeutic Guidelines Limited; 2018 Jul. https://tgldcdp.tg.org.au/ (accessed Dec 2018).
2. BMJ Best Practice. Adhesive capsulitis (updated Apr 2018; reviewed Nov 2018). https://bestpractice.bmj.com (accessed Dec 2018).
3. BMJ Best Practice. Rotator cuff injury (updated Apr 2018; reviewed Nov 2018). https://bestpractice.bmj.com (accessed Dec 2018).
4. BMJ Best Practice. Joint dislocation (updated May 2018; reviewed Nov 2018). https://bestpractice.bmj.com (accessed Dec 2018).
5. NPS Medicinewise. Non-traumatic shoulder pain in general practice: a pragmatic approach to diagnosis (6 Jul 2018). https://www.nps.org.au/news/non-traumatic-shoulder-pain-in-general-practice-a-pragmatic-approach-to-diagnosis (accessed Dec 2018).
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