This website is under development - The information contained on this site is for guidance only and is not intended for self diagnosis or self treatment. This will not replace professional medical advice or consultation. Always seek the professional advice of a qualified health care provider like your doctor or specialist before embarking on any treatment. If you have a problem please consult your doctor or specialist.
What is it?
Dislocation refers to the disassociation between the ball formed by the upper arm bone (Humeral head) and the socket formed by the shoulder blade(Glenoid).
Subluxations are episodes when the shoulder does not truly dislocate but moves into a perched position ready to slip out. The humeral head moves out of the center of the socket and goes to the rim of the socket.
The most amazing feat is for the joint to stay in place despite the extreme mobility between the shallow socket and the oversized ball. The shape of the bone has little to contribute in the form of stability unless it is damaged in a significant way.
The stability comes from the delicate but robust balance between various muscle group around the shoulder socket. These get their feed back from the sensors that are present in various joint structures including cartilage rim (labrum), ligaments and capsule. Thus, location of sensors, feedback loop, appropriate muscle contraction and to some extend the structural integrity work together to keep shoulder joint in place.
In my minds eye, the lynch pin in the loop is the muscle control. When there is no muscle control, the shoulder is very much likely to dislocate even when other parameters are normal. Even when there is damage to sensor (labral tear) or where there is a small fracture in the vulnerable place, one can keep the shoulder in place with good rehabilitation techniques.
Dislocation tends to occur in younger age group and once a physical damage has been established, it rarely heals despite the age!
Symptoms of subluxation/dislocation include sensation of vulnerability, avoidance of certain movement, clicks, subluxations, “locking episodes”, “pseudo-dislocation” episode. One may also describe a “dead-arm” feeling.
When the shoulder dislocates, one knows! Unless you are a movie star who can hit the shoulder on lamp poles to relocate, I recommend that you should seek medical help to reduce the joint. The longer one leaves the shoulder out of joint, the more difficult it become to reduce the joint.
Violent dislocation can result in damage to vital structures like nerves (in particular axillary and musclulo-cutaneous nerve) or indeed fractures to either the socket and or the upper arm bone. Such events needs to be recognised before making any attempt to reduce.
Acute dislocations are best reduced in hospital under anaesthetic. In some instances, when there is no associated fractures and when muscle spasm has not fully set in, reduction can be done under sedation especially in those with recurrent episodes.
Recurrent dislocations require further investigations (like MRI arthrogram and/or CT scan) and may have to be addressed with appropriate surgery.
Surgery can be done via arthroscope (to reattach cartilage and tighten the ligaments - see below) or via open technique (to reattach a bone fragment or tighten capsule/joint liner).
On occasions one may have to place a bone block to deepen the socket to prevent dislocations and allow the patient to participate whole heartedly in the rehabilitation.