Joint dislocation

The incidence of recurrent instability for those under 25 years of age, treated non-operatively with or without sling immobilisation, ranges from 50% to 95%. [52] [53] [25]

Inadequate analgesia is also a common reason for failure in attempts to reduce a shoulder.

This is a compression fracture on the posterolateral corner of the humeral head, which is caused when the humeral head impinges against the glenoid (scapula) of the shoulder joint. [59]

Hill-Sachs lesions occur in 47% to 65% of primary shoulder dislocations. [59]

Large Hill-Sachs lesions are associated with recurrent joint instability. [54]

These are avulsions of the glenoid labrum and its attachment to the inferior glenohumeral ligament. This ligament is a primary restraint of the humerus to anterior/inferior translation when the arm is in abduction. [60]

Avulsion of the capsular restraints to the humeral head contributes to the incidence of instability after a dislocation.

Bankart's lesions occur in up to 78% of primary shoulder dislocations. [60]

Large Bankart's lesions are associated with recurrent instability. [54]

Elbow dislocation with associated fractures, particularly of the radial head and coronoid, often results in significant instability of the joint. [58]

Fractures, particularly of the radial head and coronoid, are found in approximately 20% to 50% of elbow dislocations. [14] [58]

Posterior dislocation of the elbow associated with a fracture of the coronoid process and the radial head is described as the "terrible triad".

Recurrence rates for patellar dislocation range from approximately 50% to 71% of patients with non-operative treatment.

see our comprehensive coverage of Rotator cuff injury

These occur in 11% to 28% of acute shoulder dislocations and are associated with worse prognosis. [44] [60]

Older patients are more likely to sustain rotator cuff injuries, and early MRI scan may be helpful to rule out this associated pathology. [21] [43] [44]

The incidence of axillary or brachial plexus injuries associated with acute shoulder dislocation is approximately 4%.

However, most are palsies and resolve within 3 to 6 months. [61]

Brachial and/or axillary artery injuries present with the pathognomonic triad of anterior shoulder dislocation, a diminished or absent pulse, and expanding axillary mass.

This typically occurs in older patients due to loss of elasticity of the vessels.

Any patient presenting with this triad requires emergent vascular consultation and an angiogram. [62]

These occur in 7% of shoulder dislocations and, if displaced more than 0.5 cm, they require surgical fixation. [63]

Early follow-up is important, as non-displaced fractures may displace prior to healing.

see our comprehensive coverage of Brachial plexus injury

The median, ulnar, or radial nerve can be damaged following elbow dislocation, but most cases are neuropraxias and typically resolve.

However, if a deficit appears after reduction of the elbow, consultation to orthopaedics is warranted for emergent exploration of the affected nerve. [10]

Brachial artery injury is an extremely rare but devastating complication of elbow dislocation.

If a patient presents with an asymmetrical pulse, immediate reduction should be performed, with assessment of pulses post-reduction and referral to a vascular surgeon.

If pulses do not return, the patient requires immediate surgical intervention to repair the artery.

Several studies have shown better outcomes with early mobilisation than with immobilisation in patients with simple dislocations of the elbow.

Patients should initially be splinted in a posterior splint for comfort, with instructions to begin mobilisation when pain allows. Immobilisation should last no longer than 2 weeks. [14] [47] [48] [49] [50]

These occur as cartilage covering the end of a bone in a joint (articular cartilage) is torn.

One case series found 95% of patients with lateral patellar dislocation showed some degree of articular cartilage injury; cracks with osteochondral fracture were seen in 54% of knees. Other studies have reported rates of between 40% and 76%. [64] Damage can occur as a result of reduction in addition to the initial dislocation.

Large osteochondral injuries require internal fixation, while small injuries may require arthroscopic debridement.

Therefore, orthopaedic consultation is necessary should an osteochondral injury occur.

Other ligamentous structures around the knee can be concomitantly injured.

Stiffness in finger dislocation is more common than instability and can cause residual pain and stiffness for 6 to 12 months after injury. [23] [26] [30]

In treating finger dislocation, instituting early motion and providing stability must be balanced.

Chronic dorsal PIP dislocation may result in a swan neck deformity of the finger. [26]