The conservative treatment of dislocations of the shoulder is a controversial matter in orthopedics, with management in a sling for anything from one to six weeks. An immobilising strap may be applied around the waist but this is not universal. The arm is kept in to the side with the forearm across the abdomen (officially internal rotation and adduction) to prevent stresses to the injured areas, avoiding arm away from the body and moving it outwards (officially external rotation and abduction).
Recent scientific studies have given new ideas on why these injuries should be immobilised in particular ways. One study done via MRI scanning showed that the socket and the fibro-cartilage rim, which is often damaged, were kept in most intimate contact with the arm by the side and the shoulder externally rotated at thirty-five degrees. A second study performed with dead bodies showed a reasonable range of movement where the two important structures are closely applied if the arm is in slight adduction. Bringing the arm forwards (flexion) or out sideways (abduction) tended to disrupt the joint rim.
How long a person should be in a sling is not clear and wearing a sling for three to four weeks is common in younger people with perhaps a bit shorter for older patients. One study indicated that the chances of the shoulder dislocating again was reduced by having a longer period of immobilisation. However, another long study following patients over 10 years did not find any effect on the recurrence rate by the period they were immobilised. At the three or four week point the patient is usually reviewed by a physiotherapist and rehabilitation started.
Rehabilitation starts with pendular exercises which allow range of motion of the shoulder joint without high levels of stress through the area. The patient bends at the waist and permits the arm to hang vertically, making movement easy. Physiotherapists will teach scapular movements to maintain range of this area and progress the patient towards active assisted exercises next. Muscle function and range of movement can be facilitated by using the unaffected arm to participate, thereby allowing increased but controlled forces to be applied.
External rotation will initially be limited due to the re-dislocation risk and gradually allowed to increase as the weeks go on, but it is never pushed strongly and there may be an advantage to the patient if they lose some range of this movement. This may protect them from easily going into the risky and vulnerable dislocating position again. At six weeks much of the soft tissue healing will be well advanced and patients can start doing full active range of movement and strengthening exercises for the shoulder and shoulder girdle.
Stronger rehabilitation can be pursued if the patient needs high performance from their shoulder but four months should typically elapse before overhead sports practise will be wise. Older patients or those with greater tuberosity fractures (a bit of the upper arm bone where tendons attach) have a somewhat better prognosis. Modification of a patient’s typical activities may be required by limiting arduous work, controlling overhead activities and deciding not to indulge in sporting activities which carry increased risks.
Thirty percent is the overall re-dislocation rate for those of us who are not athletic, and this rises very steeply to 82 percent in sports people and athletes. How old the patient is has a strong influence on how likely they are to dislocate again, with under ten years having a 100 percent likelihood of re-dislocation. Older people in their forties have a much reduced chance between nought and twenty four percent. Repetitive re-dislocation may mean that a patient requires surgical intervention to prevent further episodes of joint problems.
When a problem shoulder should be surgically managed is not generally agreed but surgery early after the dislocation may be helpful. Scientific studies vary but in one there was only a four percent re-dislocation after arthroscopic shoulder stabilisation compared to a 94 percent re-dislocation rate in those managed non-operatively. Conservative treatment may have higher recurrence rates than those managed surgically. Open surgery used to provide better stability results but newer techniques with the arthroscope have meant that this technique is now as good.