What is a shoulder dislocation?
The shoulder joint is classified as a ball and socket joint where the humerus meets and fits into the scapular. This is one of the most mobile joints in the body because it moves in several directions and therefore is it more susceptible to dislocating. If you experience a dislocated shoulder, it means that your humerus has popped out of the socket that is a part of your shoulder blade. Signs and symptoms you may experience is visual deformity, swelling or bruising, intense pain and inability to move the joint.
This type of injury takes a strong force or extreme rotation to pull the bones out of place, such as a sudden blow. There are two types of shoulder dislocations that can result from such impact: An anterior or posterior dislocation of the joint.
These may be caused by:
Sports injuries. Such as contact sports (e.g. football), and in sports that may involve falls (e.g. gymnastics and volleyball)
Trauma not related to sports - such as a motor vehicle accident
Falls. You may dislocate your shoulder during a fall (e.g. tripping over a rug or falling off a ladder)
The first type of shoulder dislocation we will discuss is the most common. An anterior dislocation makes up 97% of all recurrent or first time shoulder dislocations. The positioning of the arm that is usually linked with this is when it is abducted, external rotated and in extension. In this position, the inferior glenohumeral complex serves as the primary restraint however, there is a lack of ligamentous support and stabilisation. Therefore, it is most susceptible to dislocating and is a very common contact sports injury.
When an anterior dislocation occurs, the displaced humeral head stretches and typically tears resulting in a loss of integrity of the anterior ligamentous capsule. In result, this increases the laxity and mobility further and poses a greater risk of recurrence if not properly rehabbed and strengthened.
They are usually managed conservatively but surgical repair may be necessary for those who require extreme usage of the upper arm such as elite athletes or people who have failed conservative care. For a non-surgical approach, a closed reduction would be done by a physician, however, the integrity of the shoulder can be surgically repaired via stabilisation procedures. After either one, the physician will give a specific protocol for the patient to follow however the management is fairly similar.
Posterior dislocation Experiencing a posterior dislocation is less common and accounts for 3% of shoulder dislocations. It is usually caused by an external blow to the front of the shoulder. There is an indirect force applied to the humerus that combines horizontal adduction and internal rotation. This is usually the result of one falling on an out stretched hand (FOOSH injury), MVA, or seizures. Due to the traumatic mechanism of injury, posterior dislocations may also have concurrent labral or rotator cuff pathology.
Treatment: Wang and colleagues three phase protocol
To ensure successful healing and normal function of the shoulder joint, structured physical therapy is aimed at reducing muscle wasting and maintaining mobility. Early on, isometric exercises are prescribed while the joint is immobilised.
Phase 1 (up to 6 weeks): Maintain anterior-inferior stability
Immobilisation in 10 degrees external rotation to allow contact between glenoid labrum and glenoid and allow for adequate capsular healing
Sling: 3-6 weeks <40yr and 1-2 weeks >40yr
Increase active range of motion of the elbow, wrist and hand and reduce pain
Isometric exercises for the rotator cuff and biceps muscles
AAROM for external rotation (0-30º) and forward elevation (0-90º)
Phase 2 (6-12 weeks): Restore adequate motion, specifically in external rotation
AAROM to achieve full range of motion
When stretching is permitted, passively stretch the posterior joint capsule through the use of joint mobilisations or self-stretching
No strengthening or repetitive exercises should start until achievement of full range of motion
Phase 3 (12-24 weeks): Successful return to sports or physical activities of daily living
Begin strengthening exercise in a pain-free motion with exercises for stability
Start by focusing on the rotator cuff musculature and scapular stabilisers (trapezius, serratus, levator scapulae, and rhomboids)
Progress to the larger musculature such as the deltoids, latissimus dorsi, and pectorals
Start focusing on functional exercises and proprioceptive training
Management follows the same progression as anterior protocol, except for the following guidelines:
Avoid flexion with adduction and internal rotation
Avoid posterior glide
Immobilised 3-6 weeks <40yr and 2-3 weeks if >40yrs
Focus on strengthening infraspinatus, teres minor and posterior deltoid
Resistance Sports Science Practicum Student