Description, causes, prevention, treatment and medicines
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 (which is a fluid-filled pad that sits under the highest part of the shoulder). 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), heavy lifting, trauma, or poor posture. 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.
The exact cause of this condition is not known, but it sometimes develops following other shoulder injuries. 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.
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.
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 to 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.
Arthritis
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.
Diagnosis
Your doctor may be able to determine the cause of your pain based on your symptoms and a 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. Your doctor will also test your shoulder strength and the range of movement in your shoulder joint.
You may also need to have an X-ray, or other scans, such as an ultrasound scan or MRI. Sometimes, an arthroscopy is needed. In this test, 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.
Pain relievers such as paracetamol and non-steroidal anti-inflammatory drugs (NSAIDs) are often used as an initial treatment for shoulder pain. 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.
You should also rest the shoulder for a couple of days after most injuries, and 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. While you should 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 the 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 massage, ultrasound therapy, laser therapy and transcutaneous electrical nerve stimulation (TENS) — a therapy that uses mild electrical currents to treat pain. 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
Because most people improve with the above treatments, only about 10 per cent of 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 an operation, including some rotator cuff tears and dislocated shoulders that cannot be reduced (put back in) with simple manual manoeuvres.
Sometimes 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. Arthroscopic surgery (surgery performed with a special tubular instrument that is inserted through an incision in the shoulder joint) is another treatment that may be tried for frozen shoulder.
Arthroscopic surgery is also a treatment option for SLAP tears of the shoulder.