The shoulder joint is a ball and socket joint. The end of the upper arm bone (humerus) is ball shaped and fits into the shallow cup-shaped socket of the shoulder blade (glenoid). It is very mobile joint allowing us to move our arms in all directions, but this also means it easy to dislocate. The arm bone can come out of the joint in a forwards, backwards or downwards direction and can dislocate completely or partially.
Sometimes the shoulder joint can dislocate easily and recurrently and is therefore an unstable joint.
Signs and Symptoms
Most shoulder dislocations are caused by a significant injury such as falling on an outstretched hand or from a blow to the shoulder. However, some people experience a dislocation after a minor injury and may notice a pop as the arm bone moves back into place. These dislocations can occur in people with lax joints. There are a few people who experience recurrent dislocations with no traumatic cause because the muscles around the joint do not work correctly.
When the shoulder dislocates for the first time, patients experience severe pain and notice the shoulder is weak and appears deformed. If the nerves around the shoulder have been stretched, there may be numbness or tingling in the arm and hand.
Patients with an unstable shoulder that dislocates repeatedly may experience a range of symptoms from pain in certain position to the shoulder joint popping in and out.
The diagnosis is usually obvious at examination but an X-ray is carried out to confirm the position of the arm bone and to exclude any broken bones.
In cases of recurrent dislocation, an MR arthrogram, where dye is injected into the joint during an MRI, may be organised.
Most first shoulder dislocations caused by trauma are put back in position in the Accident and Emergency department. A muscle relaxant and sedative are used to ease the pain and allow the arm to be manipulated. Very occasionally a general anaesthetic may be needed. A sling is worn for a period of time following this to rest the shoulder. Sometime physiotherapy may aid recovery.
If the shoulder goes on to repeatedly dislocate, further treatment will be necessary and includes:
• Physiotherapy – This is useful when the shoulder dislocates in situations that are not traumatic. It is most effective if the instability is caused by muscle imbalance around the shoulder.
• Arthroscopic Surgery – During this keyhole procedure, the torn cartilage is repaired.
• Open Surgery – If there is significant bone loss an open procedure may be advised.
During your consultations, the results of all your investigations will be discussed with you. Mr. Singh then takes these into consideration together with your symptoms, lifestyle (and opinions) to develop your treatment plan. The details of all available procedures will be explained to assist you in the decision making process.