Shoulder is the most mobile joint in the body, stabilised by a number of ligaments. However, it is also the most commonly dislocated joint in the body. The most common ligamentous injury following dislocation of the shoulder is detachment of the Glenoid Labrum from the Glenoid (bony socket). This is called Bankart lesion.
Most shoulder dislocations are a consequence of an injury. This is called a Traumatic dislocation, and most commonly the shoulder comes out through the front (anterior dislocation). A dislocation to the back of the shoulder (Posterior) is rare and may occur due to a blow to the front of the shoulder or after an epileptic fit.
However, sometimes the shoulder may dislocate slip out partially (sublux) without any injury. This is called Atraumatic instability, and may be due to the ligaments being lax. Some of these patients may have laxity of other joints, and may be able to dislocate their joints voluntarily.
Most traumatic dislocations need a period of sling immobilsation after the dislocated shoulder is reduced (put back). This is followed by period of physiotherapy to regain range of movements and strengthen the muscles.
There is a high risk of recurrent instability after a traumatic dislocation especially in young patients. The shoulder may dislocate easily on doing day to day tasks. In some patients recurrent instability may manifest as pain in the shoulder in certain positions or return to normal sporting activities.
In case of recurrent instability further scans may be needed. These are MR Arthrogram in which a dye is injected into the shoulder, before doing an MRI scan. This gives details information about the extent of ligamentous injury, and also any associated injury to the rotator cuff.
A CT scan may also be needed. This gives information about bones of the shoulder joint, to plan treatment.
Surgery may be needed in case of recurrent traumatic instability of the shoulder.
Arthroscopic stabilization- This is a keyhole procedure which involves reattaching the detached capsule and labrum back to glenoid. This is done using bone anchors, which are inserted into the bone (see animation and video).
Postoperatively the shoulder is immobilised in a sling for about 4weeks, followed by physiotherapy.
The patient can return to light gym work in about 3months, and return to sport in about 6months.
Latarjet- Occasionally reattachment of the ligaments may not be possible or there may be bone loss on either the head of the humerus or the glenoid, It involves transfer of coracoid (a bony process arising from the front of the shoulder blade) with it muscle attachments to the front of the glenoid. This is fixed using two screws.
The operation is usually performed as an open procedure with a scar at the front of the shoulder.
Postoperatively the shoulder is immobilized in a sling for a period of about 6 weeks.