Joint Dislocations: Shoulder, Elbow, Hip, Patella and Ankle
Joint dislocation refers to complete displacement of the articulating bones within a joint, resulting in loss of normal joint alignment.
Shared findings / general concept:
- General presentation
- Significant pain (esp. on joint movement)
- Refusal / inability to move the joint
- Characteristic joint position / deformity (see below)
- Joint tenderness and swelling
- Initial assessment
- Neurovascular assessment
- Assess the joint above and below (as associated fractures are common)
- Management principle: reduction → immobilisation → monitoring
This article focuses on selected high-yield closed joint dislocations relevant to the UKMLA and day-to-day clinical practice.
Shoulder Dislocation
Types and Causes
| Dislocation type | Causes / mechanisms |
|---|---|
| Anterior shoulder dislocation (90-95% cases) |
Strong forces required to displace the shoulder usually result from contact sport injuries, motor vehicle accidents, and severe falls |
| Posterior shoulder dislocation | Causes of violent involuntary muscle contraction, such as:
Direct blow to the anterior shoulder combined with axial loading while the arm is adducted and internally rotated |
Risk Factors
- Prior dislocations – major risk factor
- Previous dislocation may tear the glenoid labrum, stretch or tear the joint capsule and surrounding ligaments (esp. the anterior glenohumeral ligament for anterior shoulder dislocations), which makes the joint more prone to dislocate
- Younger patients (due to generally higher activity levels)
- Shallow glenoid fossa
- Associated shoulder injuries (e.g. rotator cuff tears, glenoid fracture)
Clinical Features
| Dislocation type | Clinical presentation |
|---|---|
| Anterior shoulder dislocation (most common) |
In thin patients, a prominent humeral head may be palpable anteriorly, just below the coracoid process |
| Posterior shoulder dislocation |
In thin patients, a prominent humeral head may be palpable posteriorly |
Associated Injuries / Complications
Hill-Sachs lesion: compression / depression fracture of the posterolateral humeral head
Bankart lesion: injury to the glenoid labrum
- Soft Bankart lesion (more common): labral tear without associated fracture
- Bony Bankart lesion: labral tear with an avulsion fracture of the glenoid rim
Assessment and Management
| Step 1 | Clinical assessment
Pre-reduction imaging with X-ray (to help confirm the dislocation and exclude associated fractures) If there is an associated humeral neck fracture, do NOT perform reduction in the emergency department as it can lead to avascular necrosis. [Ref] |
| Step 2 | Provide adequate analgesia and perform reduction:
After successful reduction → immobilise the arm with a sling
|
| Step 3 | Perform post-reduction assessment
|
X-Ray Findings
| Dislocation type | Radiographic findings |
|---|---|
| Anterior shoulder dislocation | The humeral head is typically displaced anteriorly and inferomedially
Associated injuries such as Hill-Sachs and Bankart lesions should also be assessed for |
| Posterior shoulder dislocation | Posterior dislocation may be subtle on AP X-ray. Typical findings include:
|
Elbow Dislocation
| Section | Content |
|---|---|
| Type | Posterior elbow dislocation is the most common type
This involves posterior displacement of the ulna and radius relative to the humerus |
| Causes | Elbow dislocation usually occurs following high-energy trauma or sporting injury
A common mechanism is FOOSH |
| Clinical features |
|
| Terrible triad injury | Triad of:
This is an unstable fracture-dislocation and often requires surgical management |
| Assessment | Assess neurovascular status; important structures to assess include:
1st line investigation: X-ray |
| Management |
|
As a general rule, dislocation with ANY of the following would require urgent orthopaedic evaluation +/- operative management:
- Neurovascular compromise
- Open injury
- Associated fracture
- Failed closed reduction or post-reduction instability
Hip Dislocation
| Section | Content |
|---|---|
| Type | Posterior dislocation is most common (~90% cases)
Anterior dislocation is less common |
| Causes | Usually caused by high-energy trauma
It may also occur in patients with a prosthetic hip replacement, where lower-energy mechanisms (e.g. reaching the extremes of prosthetic joint ROM) can sometimes cause dislocation. |
| Clinical features | Typical symptoms:
Lower limb deformity / appearance depends on the type of dislocation:
|
| Complications | Key complications include:
|
| Assessment | Assess neurovascular status (sciatic nerve in posterior dislocations)
1st line investigation: X-ray |
| Management | Reduction must be performed within 6 hours to prevent permanent complications like AVN
|
As a general rule, dislocation with ANY of the following would require urgent orthopaedic evaluation +/- operative management:
- Neurovascular compromise
- Open injury
- Associated fracture
- Failed closed reduction or post-reduction instability
Patella Dislocation
Common causes / mechanisms (common during sports):
- Twisting injury
- Sudden change in direction
- Direct blow to the medial side of the patella
Clinical presentation:
- Lateral dislocation of the patella is most common (→ lateral prominence)
- The knee would be held in flexion
Assessment and management:
- Neurovascular status assessment
- Patella dislocations commonly reduce spontaneously
- If dislocated on presentation
- Closed reduction
- Encourage unrestricted weight-bearing
- Splints that permit full knee flexion may be used for pain relief
Ankle Dislocation
Ankle dislocation rarely occurs in isolation, most occur with concurrent ankle fracture (fracture-dislocation)
See the Ankle Fracture article for more information.