The anatomy of the shoulder is comprised of several joints. The largest and most important of these joints is known as the glenohumeral joint which is a ball and socket articulation between the upper arm bone (humeral head) and the edge of the shoulder blade (glenoid). A dislocation of the shoulder is a specific injury in which the humeral head is forced out of the glenoid. Almost all shoulder dislocations are referred to as an anterior dislocation which describes a dislocation of the humeral head out of the front of the glenoid.
Dislocation of other joints within the shoulder complex can occur but are are not referred to as a shoulder dislocation.
The majority of shoulder dislocations are caused by an injury, normally while playing sport. The most common injury mechanism is a forced rotation to the shoulder while the arm is placed away from the torso. Common examples include:
- Tackling injuries in rugby
- Heavy falls on to an outstretched arm
- Awkward landing from jumps (with the body overturned)
In less common cases, shoulder dislocations occur without any obvious trauma to the shoulder. In these cases there will be one or more underlying factors which make the shoulder more susceptible to dislocating. These include:
- Hypermobility syndrome (sometimes referred to as Ehlers-Danos Syndrome)
- Shallow glenoid socket
- Pre-existing injuries to the shoulder (rotator cuff tears, glenoid labral tears, fractures)
If there is immediate, specialist medical attention available (such as pitchside physiotherapists or doctors) a shoulder dislocation can sometimes be relocated if done immediately.
Unless immediately relocated, a dislocated humeral head will rest in a position underneath the glenoid shoulder socket and the shoulder muscles will not allow movement of the shoulder. These cases have to be treated in an accident and emergency department.
An initial x-ray will be taken to ensure there are no large, unstable fractures to the shoulder. Once cleared, the shoulder socket will be relocated under pain medication and sometimes a light anaesthetic.
Due to the shoulder joint’s shallow socket, the joint normally relies on a variety of soft tissue structures to stabilise the shoulder joint. These structures include tears to the tendons of the rotator cuff muscles which help to stabilise the joint during movement. Tears to the shoulder joint capsule as well as tears to a structure known as the labrum which deepens the shoulder socket may also occur. Normally, one to two weeks rest in a sling with certain movement restrictions is advised to aid the healing of these structures following a shoulder dislocation.
Even with appropriate initial treatment, shoulder joint re-dislocation is a very likely occurrence. The chance of re-dislocating increases in younger patients, increases with each further dislocation and is more likely for younger patients. Furthermore, there are specific types of soft tissue injury and fractures which are only reliably diagnosed under consultation with an experienced consultant shoulder orthopaedic specialist.
Circle Health is able to offer short notice appointments with expert shoulder orthopaedic consultants following a shoulder dislocation. Following history taking and a shoulder physical examination, we are able to offer immediate booking for diagnostic scans and follow up orthopaedic consultations to discuss possible surgical solutions.
Diagnostic scans may include ultrasound scans to best evaluate the tendons of the rotator cuff, MR arthrograms (MRI scan with contrast dye injected in to the shoulder) to evaluate the labrum and possibly CT scans to examine any fractures not picked up on x-ray.
Using any diagnostic imaging as a guide, initially the shoulder surgeon will examine these areas of known damage with a keyhole camera known as an arthroscope. Once examined, surgery will aim to the relevant shoulder defects.
Tears to the rotator cuff tendons and glenoid labrum will be carefully stitched together. The anterior (front) of the shoulder capsule and ligaments will be pulled tight across the front of the shoulder joint and secured with an anchor. This restricts shoulder range of motion slightly but stabilises the shoulder joint preventing further dislocations.
Fractures to the rim of the glenoid are normally repaired using a thin piece of bone from the front of the shoulder blade known as the coracoid process (laterjet procedure) or repaired with a larger bone graft from the crest of the pelvis (sheffield bone block).
Physiotherapy is needed for several months after these stabilisation procedures to get the best possible outcomes for patients.
In some circumstances, patients may opt for a non-surgical approach to managing a shoulder dislocation. In these circumstances, patients will be managed by Circle Health’s expert physiotherapists who have the experience needed to progress exercises safely and effectively.