Dislocation of the Shoulder - Part Two
The management of dislocated shoulders is a matter of controversy in the orthopaedic field, with the usual management being confined to a sling for between one and six weeks, with or without a strap around the waist to prevent external rotation. The arm is maintained close to the body with the forearm across the belly, a position known as medial rotation and adduction. This avoids the stresses which would be applied to the joint if it were moved to the side or outwards, known as lateral rotation and abduction.
Recent studies of dislocation in the scientific literature have shown some clues as to how these injuries should be managed. One study involved MRI scanning to show that the relationship between the rim of the socket and the socket itself is best maintained by placing the arm by the side and rotating it laterally 35 degrees. A cadaveric study of shoulders showed that keeping the arm in slight adduction close to the body allowed a reasonable range of motion without disrupting the close approximation of the structures. Lifting the arm up forwards or out to the side (flexion and abduction) disturbed this relationship.
The length of time someone should spend in a sling is not a matter of agreement and a typical time of 3-4 weeks for young people with a shorter time for an older patient is common. The rate of having a second dislocation was indicated to reduce in one study by having a longer time in a sling, but another study, tracking patients over ten years, showed no difference in re-dislocation rates whatever times of immobilisation were used. The physiotherapist will normally review a patient at the three to four week mark and begin rehabilitation.
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.
Overall the incidence of re-dislocation of the shoulder is around 30 percent in non-sporting people but rises to eighty-two percent in those in athletic sports. The age of the patient is however very important in determining the recurrence rate. There is a one hundred percent chance of dislocation recurrence in patients under 10 years old and only zero to 24 percent likelihood in patients who are in their forties. Surgical management may be required should a patient suffer from recurrent dislocation of the shoulder.
The timing of surgical management is not clear although early surgery after the initial dislocation may be advantageous. Studies vary but one showed that after stabilisation surgery via the arthroscope there was a four percent dislocation rate but a 94 percent repeat dislocation rate after conservative treatment. Overall it looks like the recurrence rate is higher for those patients managed by non-operative immobilisation. The level of stability given in operation was better with open surgery but arthroscopic techniques have advanced considerably and this distinction has disappeared.