Elbow Disorders (Session 8) Flashcards
(74 cards)
How might someone acquire a supracondylar fracture of the distal humerus?
1-Falling from moderate height w./ elbow hyperextended (e.g. child falling off monkey bars) 2- Falling on flexed elbow
In what age groups are supracondylar fractures most common?
Children <10yrs (more common in boys)
How may a child who has suffered a supracondylar fracture of the distal humerus present?
Pain, deformity, loss of function
In which direction is the distal fragment usually displaced?
Posteriorly
What are the 3 main complications following a supracondylar fracture of the distal humerus?
1, Malunion- results in cubits varus (gunstock deformity)
2, Damage to median/radial/ulnar nerve
3, Ischaemic contracture
What is an Ischaemic contracture? i.e. How does it come about if a patient has suffered a supracondylar fracture of the distal humerus?
- Brachial artery damaged/occluded by displaced fracture-
- reflex spasm of collateral circulation
- ischaemia in anterior compartment of forearm
- oedema + rise in pressure- compartment syndrome
- dead muscle tissue- replaced- scar tissue
- flexion contracture- Volkmann’s ischaemic contracture
How can Volkmann’s ischaemic contracture be characterised?
- Wrist=flexed
- Fingers=extended at metacarpophalangeal joints
- Forearm pronated
- Elbow flexed
What measures can be taken to minimise the risk of complications following a suprachondylar fracture of the distal humerus?
Prompt examination- neurovascular system- if compromise to supply- emergency reduction and fixation of fracture
Explain the common mechanism for elbow dislocation?
FOOSH with elbow partially flexed
Why is a dislocation of the elbow more likely if the elbow is is in mid-flexion?
Configuration of elbow mean that:
- Bone most stable in full extension and flexion
- Stabilty in mid-flexion=more reliant on ligaments
Which joint is the most common to dislocate in children?
Elbow
(2nd most common in adults)
What % of elbow dislocations do sports injuries account for?
50%
What % of elbow dislocations are posterior?
90%
Which way do the bones at the elbow joint move in a posterior dislocation?
- Distal end of humerus- driven through joint capsule anteriorly
- Ulnar collateral ligament (usually torn)
- (Often) Fracture/ulnar nerve involvement
What’s the usual mechanism for anterior dislocations (<10% of anterior dislocations)?
Direct blow to posterior aspect of flexed elbow
Remember: displacement of distal fragments (ulnar and radius) in the type of dialocation (anterior/posterior)
What fracture is commonly associated with an anterior dislocation of the elbow (due to the force required)?
Olecranon fracture
What’s another name for a ‘pulled elbow’?
‘nursemaids elbow’
What has occured if a patient has a ‘pulled elbow’?
Subluxation of radial head
(Subluxation= partial disruption of joint with some remaining but ABNORMAL opposition of articular surfaces = incomplete dislocation)
In which age group does a ‘pulled elbow’ most commonly occur?
Children age 2-5
How will a child with a pulled elbow present?
- Reduced movement of elbow
- Pain over lateral aspect of proximal forearm
What are the mechanisms of injury for a pulled elbow?
- Longitudinal traction applied to arm with forearm pronated (eg swinging child by their arms) (50%)
- Falls
- Over-reaching for an object
Why does a pulled elbow more commonly occur when the forearm is pronated?
- Annular ligament taut in supination
- Annular ligament more relaxed in pronation
Logitudinal traction on radial head- tears annular ligament from radius
Radial head displaced distally through torn ligament
Why does a ‘pulled elbow’ injury become less common as the child ages?
Annular ligament natural strengthens
Radial head and neck fractures are the commonest type of elbow fracture.
What is their usual mechanism of injury?
FOOSH
