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 Proximal Humeral Fractures 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.