The shoulder is a type of joint known as a ball and socket joint. This means that the head of the humerus (the bone in the upper arm) fits into a small fluid cup made out of cartilage, known as the labrum. This allows for support of the humerus and produces a full range of motion in the shoulder joint. However, in a shoulder dislocation, the humerus comes out of the labral cup, resulting in pain and a relative inability to move the arm.
Types of Dislocated Shoulders
There are two main kinds of dislocated shoulders. A anterior dislocation occurs when the head of the humerus is knocked out of the shoulder joint to the anterior (the front) of the body, and can be caused by falling on an outstretched hand or by trauma to the back of the shoulder. A posterior dislocation, which is less common, generally occurs due to a sudden blow to the front of the shoulder. In general, anterior dislocations heal more quickly than posterior dislocations.
Treatment and Timeline
The initial phase of treatment is to push the head of the humerus back into the shoulder joint. This is most easily done immediately after the dislocation, as after 30 minutes or so the joint becomes swollen and stiff. If this happens, IV pain medication or muscle relaxants may be necessary to push the joint back into place. Afterward, the doctor will place the injured arm in a sling which will immobilise the joint. This sling should be worn for two or three weeks. After that, physiotherapy will be prescribed to continue the healing process.
There are two main complications for which a physician will look. The first and most worrisome is any tingling, numbness or loss of sensation in the arm, which could indicate a damaged or severed nerve. If this is the case, surgery may be required to repair the nerve to avoid permanent loss of sensation. The other complication is a fracture of the humerus, which can be due to the trauma of having the head ripped out of the shoulder joint. This can be diagnosed with an X-ray, and a fractured humerus will increase the healing time and may need orthopaedic surgery.
Overall Healing Time
In general, a dislocated shoulder will fully heal within four to 12 weeks. Exactly how long the recovery time is depends on a number of factors, including the amount of structural damage to the muscles at the time of the dislocation, the age of the patient (younger patients heal faster) and the physiotherapy regimen. Once the healing process is over, the patient will have full range of motion, though some activities, such as sudden torque on the shoulder, will still cause pain for up to a year.
Importance of Therapy
The main goal of physiotherapy is to strengthen the shoulder muscles. This has two functions. Primarily, it works to help strengthen the shoulder muscles that were damaged by the shoulder dislocation as well as helps restore shoulder strength. The other function of strengthening these muscles is to help keep the shoulder joint intact in the future. Failure to comply with the physiotherapy can leave the supporting muscles weak, which will decrease the shoulder's stability, leading to a greater risk of dislocation and other injuries.