The shoulder is a ball and socket joint. Ball being the head of humerus (arm bone) and socket is a part of the scapula (shoulder blade). The socket of the shoulder is not very deep and confining. The head is therefore held & stabilized in the socket primarily by soft tissues including ligaments, tendons and muscles surrounding it.
When the humerus head separates from its normal articulation with the glenoid it is called as shoulder dislocation. There may be instances where it may only partially separate from each other more than normal. This is called subluxation.
A sudden jerk to the shoulder or an abnormal extreme movement of the arm, usually in an upward and outward movement may cause a shoulder to dislocate. This is called ‘traumatic dislocation’ and is commonly encountered in sports individuals involved in wringing movements of the arm like wrestling or in contact sports. Due to an extreme motion of the arm, tissues holding the shoulder joint tear and can no longer hold it in place. The shoulder therefore becomes unstable and dislocates or subluxates from its normal position. Depending on the side on which the humerus head dislocates, it is either anterior (front), posterior (back) or inferior (down) dislocation.
Some individuals may have an inherent laxity of tissues around the shoulder. This results in an abnormal mobility in the shoulder. They may be able to voluntarily make these abnormal dislocating/subluxating movements. These are called ‘atraumatic dislocations’ (dislocation without injury). These dislocations may not have any tears in tissues around the shoulder joint and would very often be without symptoms..
If a first time dislocation is not managed appropriately, the shoulder may not return to normal stability by itself. This is because the torn tissues around the shoulder have not healed normally and remain loose. This may cause the shoulder to be unstable and dislocate repeatedly in aggravating positions. Due to repeated occurrence of this instability it is called ‘recurrent shoulder dislocation’.
Plain X-rays of the shoulder
MRI shoulder
In certain cases a CT scan with 3D reconstruction images may be required
The diagnosis of shoulder dislocation is not difficult. Most often the patient himself would mention of his shoulder being unstable/dislocating during a particular action.
In an acute presentation, once the type of dislocation is diagnosed one should reduce (reposition) it back to normal at the earliest. For first time dislocations,this may require reduction under anaesthesia. However for recurrent dislocations, this may often be achieved without any anaesthesia.
The plan of management depends on a number of patient factors, type of the dislocation and associated injuries. The treatment may be either a non-surgical or a surgical mode of management.
Non-surgical line of treatment would involve an initial period of shoulder immobilization in a brace followed by a sports specific physiotherapy & rehabilitation to get back to normal sporting activity.
A surgical line of treatment is often advisable in shoulder dislocations of young individuals involved in high demand sporting activities. This is in order to ensure that the shoulder is restored to absolute normalcy and one can resume sports at a pre injury level without a risk of re-dislocation.
Those with recurrent shoulder dislocations always require surgery to restore stability of the joint. A majority of the surgical procedures are arthroscopic, day care procedures. Some situations where the condition has been neglected for a long duration and have developed other bony changes, may require a mini-open surgical procedure.
When the shoulder dislocates, it tears off tissues holding the joint together. Depending on the ligament and area of the labrum (rim of tissue around the glenoid) torn, they are labeled differently. When the front lower portion of the labrum along with the ligaments is torn, it is commonly called the ‘Bankart’ lesion. There are a number of other variations like the ALPSA, GLAD, Perthes, bony Bankart, posterior Bankart, HAGL etc. depending on the region and type of lesion.
Arthroscopically one can visualize these torn areas of the shoulder and repair them using special anchoring devices through keyhole incisions to restore the normal structure. A ‘Bankart’ lesion being the commonest type of tear in shoulder dislocations would require a ‘Bankart’ repair.
Depending on the variations in tear patterns, other repairs may also be necessary which are performed simultaneously.
When a recurrent shoulder dislocation is neglected for long, the bone of glenoid (socket) gets worn off and this causes a defect in the front portion of glenoid. This increases the instability and risk of re-dislocation of the shoulder.
A ‘Latarjet’ procedure fills this bone defect with a part of coracoid (bone of the shoulder blade adjacent to the glenoid) along with the muscle-tendon unit attached to it. This filling of the bone defect and action of the muscle tendon unit bring back stability to the shoulder joint. This procedure has a very high success rate with very low risk of failure.
‘Latarjet’ procedure has been modified and can be performed arthroscopic or as a mini open surgery. Current methods of arthroscopic ‘Latarjet’ procedure have a high complication rate. Further refinements in instrumentation & technique are expected to better this arthroscopic technique. A mini open procedure has a very low risk of complications and excellent outcomes therefore more favorable.
The rehabilitation protocol varies depending on the type of surgery and extent of repairs that are performed.
An average post-operative recovery :
Suture removal – 10 days
Shoulder immobilization – In brace for 2 weeks
Range of motion – Full movements by 1½ months
Return to routine activities of daily living – 3 weeks
Return to sports – 3 months