Dislocations of the glenohumeral joint are quite common in contact sports and from falls. There are two kinds of dislocation, anterior (meaning to the front) and posterior (to the back). The anterior dislocation is the most common type. They can occur when falling with the arm elevated and turned out, which is unfortunately the position which we use instinctively to protect the body when falling. They can also occur by a direct trauma or by the arm getting pulled outwards and backwards.
This pulls the head of the humerus out of the front of the joint. There is commonly a lot of soft tissue damage present to the shoulder capsule and surrounding tendons. The posterior dislocation is less common and occurs when falling onto an arm which is rotated inwards and is in front of the body. These are difficult to diagnose and often quite difficult to treat.
A person with a dislocated gleno-humeral joint will have pain and a distinct deformity in which the head of the humerus is sitting in the armpit. The dislocation can be confirmed with an X-ray.
Treatment of the gleno-humeral dislocation consists of initially getting X-rays and having a doctor reduce the dislocation. Following this the shoulder needs to be immobilised for up to three weeks to allow healing of the soft tissues and decreased pain. In younger patients and first time dislocations sometimes the immobilisation period is even longer as the risk of recurrent dislocation is very high. After this period your physiotherapist will commence a program for regaining range of motion and improving stability of the shoulder through muscular retraining.
Fractures in the shoulder can also occur as well as the dislocation and these can cause a much slower recovery.
In cases where there is recurrence of the dislocation or if there is severe soft tissue damage, surgical procedures will need to be considered.
A subluxation is essentially a mini dislocation. An unstable joint can slip backwards and forwards without completely dislocating. This slipping can cause pain during and after activity. It feels to the patient as if the joint is slipping out.
Treatment can be conservative with a muscle retraining and strengthening program, but it may require surgery to stabilise the joint.
Acromio-clavicular dislocations or sprains are quite common and can occur by a fall onto the shoulder, elbow or hand which pushes the arm up and inwards. The stability of the joint is provided by the conoid, trapezoid and coracoclavicular ligaments as well as the joint capsule and acromio-clavicular ligaments.
There are different grades of injury which indicate how much damage has been done to the injured structures:
• Grade 1 – this indicates a capsular sprain. Symptoms include pain on movement and local tenderness.
• Grade 2 – this indicates a tear of the capsule and the acromio-clavicular ligaments. Symptoms include pain and local tenderness and there is also a mild step deformity over the joint.
• Grade 3 – this is a tear of the above ligaments and capsule as well as the coracoclavicular ligament. There is pain, tenderness and a marked step deformity on the shoulder.
Physiotherapy treatment for acromioclavicular sprains and dislocations may include pain relief, electrotherapy, joint mobilisations, a strengthening program, and taping. Grade three tears will also require immobilisation in a sling for 4-6 weeks. An x-ray should also be done to exclude fractures.
Sterno-clavicular dislocations are an uncommon injury but the ligaments supporting the joint can rupture following a violent impact. The patient will have pain around the shoulder, tenderness, and an X-ray may be required to confirm. If the clavicle is displaced backwards, major blood vessels can be damaged which will require medical treatment.
Treatment involves rest and immobilisation, and surgery if required.