Instability of the shoulder

 

The shoulder can be represented schematically as a ball (the head of the humerus) balanced rather unstably on a small stand (the socket, part of the shoulder blade), rather like a golf ball on a tee. This joint, which is the most mobile in the body, must reconcile extreme mobility and stability, resulting in a fragile compromise between these two imperatives. Consequently, the joint is liable to dislocate. Capsuloligamentous structures, the ridge and the muscles that surround the shoulder joint make it possible to stabilise it. When this equilibrium is disturbed, the ball loses contact with the stand, tearing some of the aforementioned existing brakes, thus creating bone lesions "along the way".

 

The instability can manifest itself in the form of real dislocations, subluxations (incomplete displacement with the impression that the shoulder pops in and out) or simple apprehension. The dislocations are anterior in 95% of cases, posterior in 4% and inferior in 1%. Instability is possible at any age, but occurs most often in young patients.


The additional work-up includes a standard X-ray. Depending on the situation, an additional work-up in the form of an arthro-MRI or an arthro-scan may be needed to exclude any associated lesions and to organise your surgery.


The first episode is generally treated with simple immobilisation for three weeks. The aim is to relieve the pain and hope that the torn ridge will heal in order to prevent any relapse. After this, re-education, including a progressive gain in the range of motion of the joint and strengthening, is generally recommended. Unfortunately, recurrences are common. This leads to a vicious circle in which the lesions become more serious at each episode, a situation that is itself the source of more and more frequent recurrences. In case of relapse, immobilisation is only useful to ease the pain for a few days as healing is no longer possible at this stage.


A surgical treatment is indicated whenever the frequency of the dislocations or the apprehension generated is incompatible with normal daily life or the practice of a sport. The most standard interventions are, using arthroscopic procedures, either a reinsertion according to the Bankart technique (an operation that repairs and repositions the ligaments) or stabilisation in the form of a Latarjet procedure (creation of a bone block). The selection of either one of these techniques is guided by the age of the patient, the presence of hyperlaxity, well-marked lesions on the additional examinations, and the nature of any sports practised.

The complications include relapse, the persistence of pain, incomplete restoration of the range of the joint's motion, non-consolidation of the bone block and post-operative infection. These risks are well-known and everything possible is done to prevent them. For example, you will be asked to respect the recommendations and refrain from smoking for six weeks after the operation in order to optimise the chances for tissue healing.


Both these techniques generally require a one-night stay in the hospital. The arm will need rest in a sling for 10 to 30 days, depending on the techniques. If necessary, re-education will then be prescribed. You will be allowed to drive after 4 to 6 weeks.
A return to a light sports activity should be delayed for 6 weeks; contact sports should be avoided for 3 to 4 months.

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