A shoulder subluxation is similar to a shoulder dislocation, the difference being that a subluxation is temporary and partial. It can be described as shoulder joint instability. A study of over 4,000 West Point cadets showed that shoulder subluxations are much more common than dislocations, and often happen in conjunction with other injuries such as Bankart lesions.
The shoulder is a highly mobile joint, allowing the arm to move in almost any direction. The joint is formed by the connection of the humerus (the upper arm bone) and the scapula (shoulder blade). The articular end of the humerus is rounded and fits into a shallowly concave surface of the scapula called the glenoid fossa, forming a flexible ball-and-socket joint. Helping to stabilize the joint are ligaments and tendons that together form what is known as the rotator cuff.
The flexibility of the joint and the shallowness of the glenoid fossa make the joint fundamentally unstable; the humerus can quite easily be pushed out of place as a result of a trauma. If the humerus then spontaneously returns to its correct position, the incident is treated as a subluxation. During such an injury, associated tissues such as shoulder muscles, ligaments, and tendons may be stretched or torn. There may also be nerve or blood vessel damage.
Shoulder subluxations can occur as a result of a fall onto the shoulder, a heavy blow to the shoulder, or a severe twist of the arm. Sports that carry a high risk are boxing and football.
Previous shoulder injuries may increase the risk of subluxation, particularly if those injuries have been dislocations that have stretched the ligaments. If the ligaments are especially loose, subluxations can occur during normal activities.
Subluxations can also happen to people who naturally have loose ligaments; these people are sometimes called ‘double-jointed’ due to the excessive mobility of their joints.
- Sensation of your shoulder joint having gone out of position and then back in
- Pain, varying from mild pain upon performing daily activities, to severe pain during subluxation
- Instability of the shoulder joint, ranging from mild to extreme
- Weakness or numbness in the shoulder or arm
Your doctor will ask you questions about your medical history, paying particular attention to any previous injuries to your shoulder. Your doctor will want to know about the circumstances of this injury and the type and severity of any symptoms that you may be experiencing. You will also be asked about your lifestyle and regular activities. Your shoulder will be physically examined, including manipulation of the joint to assess instability and weakness. X-rays may be taken to rule out bone fractures.
Shoulder subluxation can sometimes be misdiagnosed as bursitis or a rotator cuff tear. An MRI (magnetic resonance imaging) scan can be a useful diagnostic tool, although it does not always show subluxation. An experienced orthopedic surgeon should be able to make a correct diagnosis.
Initial treatment includes applying ice to the affected area to reduce swelling and thereby relieve pain. Ice should be placed in a bag, crushed, wrapped in a towel and applied for as long as is comfortable, several times a day.
Over-the-counter pain medication such as acetaminophen (Tylenol) or NSAIDs (non-steroidal anti-inflammatory drugs) such as ibuprofen (Advil), naproxen (Aleve), or aspirin, will reduce inflammation and relieve pain.
Rest the shoulder by wearing a sling for a few days, but do not completely immobilize it in order to avoid developing a frozen shoulder (adhesive capsulitis).
After the acute phase of the injury has passed it is important that you do exercises to strengthen the muscles of the rotator cuff.
Repeated subluxations may require surgical intervention to tighten up the ligaments. Your surgeon may use arthroscopic techniques to both make a definitive diagnosis and, at the same time, repair any damage. Arthroscopy is minimally invasive as it uses very narrow instruments inserted through tiny incisions made around the shoulder. Recovery is faster than with traditional ‘open’ surgery.
Many people can make a good recovery using conservative (non-surgical) treatment as described above. Following surgery there would be a period of about 2-3 weeks when the shoulder would be supported by a sling or brace and you would be doing range of motion exercises, after which a program of strengthening exercises would begin. A full return to normal activities and sports should be achievable within six months.
Your health care provider or physical therapist will design an exercise program specifically for you, but, with medical approval, doing the following exercises will help you begin to rehabilitate your shoulder.
Range of motion:
Go carefully and gently, without forcing.
Standing with your arms straight by your sides. Keeping your elbow straight, lift your arm up as high as you can. Hold for 5 seconds. Repeat 10 times.
Stand with your arms straight by your sides. Keeping your elbow straight, move one arm backwards as far as it will go, without forcing. Hold for 5 seconds. Repeat 10 times. Repeat exercise with the other arm.
Standing with your arms at your sides, slowly lift the arms out to the side and up. Hold for 5 seconds. Repeat 10 times.
Stand in a doorway with the injured shoulder nearest the doorframe. Bend the elbow and press the back of the wrist against the doorframe. Hold for 5 seconds. Repeat 10 times for 1 set. Do 3 sets.
Standing just to the side of a doorway, bend the elbow of the injured arm and press the front of the wrist against the doorframe. Hold for 5 seconds. Repeat 10 times for 1 set. Do 3 sets.
Hold a pillow between the chest and arms. Squeeze the pillow and hold for 5 seconds. Repeat 10 times for 1 set. Do 3 sets.
Stand with your back to a wall so that your bent elbows just touch the wall. Press your elbows back against the wall and hold for 5 seconds. Repeat 10 times for 1 set. Do 3 sets.
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