The shoulder joint is the most flexible joint in the body. Is task is to enable the most different hand positions during everyday life and sport activities. For that to be possible the evolution in the shoulder area had to sacrifice stability in favor of mobility. The mobility of the shoulder is enabled by the difference in the sizes of the humerus head and glenoid cavity. This is the reason the shoulder is more prone to instability than other joints.
Sometimes the parts of the joint do not separate completely but rather partially and then the joint gets back to his normal position. This is called subluxation. If the instable shoulder completely slipped from the joint, luxation occurs.
What are the reasons for shoulder instability?
Shoulder stability greatly depends on numerous ligaments and muscles which surround it and give it stability during mobility. Shoulder instability is a problem which occurs when structures which stabilize the shoulder cannot hold the head of the humerus in the shoulder area.
It is clear that shoulder instability can occur either because of too much force affecting the shoulder (so called traumatic luxation), or too little strength of shoulder stabilizers (atraumatic luxation). With atraumatic luxation, we can differentiate voluntary and involuntary instability. If the patient can dislocate the shoulder him or herself by contracting muscles, this is called voluntary instability. If the shoulder gets dislocated spontaneously after lifting the arms, this is involuntary instability.
Direction of instability
In most cases during dislocation of the shoulder, the head of the humerus slips forward. Rarely, other directions of the head slipping are possible such as toward the back, down or multidirectional.
Duration of instability
We differentiate the luxations by duration in acute and chronic. In acute luxations, the head of the humerus is outside the shoulder joint up to 72 hours. Shoulder luxations that last more than 72 hours are called chronic. A special type of luxation is the so-called recurrent luxation in which the shoulder slips in multiple occasions. In that case, the damaged stabilizers of the shoulder become unfunctional and certain movements and arm positions lead to shoulder dislocation.
By describing the difficulties in detail and by doing clinical tests, we can orientationally conclude which instability is it all about. Radiological assessment is necessary to confirm the diagnosis.
Importance of differentiating the length of the luxation and cause of the first dislocation is big because it determines further treatment.
Acute luxation of the shoulder should be relocated gently and as soon as possible. After the relocation, immobilization of three weeks is necessary. The immobilization can last shorter in older people because of the tendency of the joint to get stiff. In case of chronic luxation, relocation is more difficult and complications and more frequent. In case the luxation of the shoulder lasts longer than 6 weeks, open relocation is necessary, as well as joint reconstruction in general anesthesia.
Independent issue in the treatment of instability is caused by repetitive shoulder dislocations. In case of repetitive atraumatic shoulder instability, non-surgical methods are preferable. Strength exercise helps the muscles to regain strength, therefore regaining their protective role in prevention of further dislocations. Proprioceptive training is useful for improving muscle activity, especially reflexes which protect the shoulder from sudden movement.
Repetitive traumatic shoulder dislocations are treater surgically. Today, arthroscopic anatomical surgeries of the shoulder are used to regain full functionality of the shoulder stabilizers. Two months after surgery normal mobility of the shoulder is expected.
Training can start four months after the operation if an athlete underwent surgery. Full load and contact sports are allowed six months after the operation and the success rate is more than 90%.
Open-type unanatomical shoulder surgeries, such as implanting bone block in the direction of the dislocation, are to be avoided because they are associated with serious future complications.
In St. Catherine Specialty Hospital, it is possible, according to new guidelines, to do diagnostic and all types of surgeries necessary for shoulder instability care. The stabilizations are done with the help of the most quality resorptive materials which have the advantage of degrading completely over time.