Elbow conditions Flashcards
What type of fracture is a fracture of the medial epicondyle of the humerus?
An avulsion fracture
What is an avulsion fracture?
Fracture where fragment of bone is pulled away from main bone mass
What is the mechanism of a medial epicondylar fracture of the humerus?
Arm is extended
Extremely abducted at elbow
Pulls ulnar collateral ligament
Pulls off medial epicondyle from rest of humerus
Which nerve is most likely injured by a medial epicondylar fracture of the humerus? Why?
Ulnar nerve
because it runs behind the medial epicondyle
What type of injury does the ulnar nerve suffer in a medial epicondylar fracture of the humerus?
Nerve traction - stretching
An elbow dislocation is usually what type of dislocation?
Posterior dislocation
What are the causes of elbow dislocation?
Falling onto outstretched hand, elbow joint flexes
Hyperextension of elbow joint
What happens in an elbow dislocation?
Distal humerus driven through anterior part of joint capsule, the weakest part
Radius and ulna move posteriorly
What are the complications of an elbow dislocation?
Tearing of ulnar collateral ligament
Fracture of coronoid process or olecranon
Fracture of head of radius
Ulnar nerve injury
What is a pulled elbow?
Subluxation of the elbow joint - incomplete dislocation
What is partially dislocated in a pulled elbow?
The head of the radius in the elbow joint and proximal radioulnar joint
What is a pulled elbow caused by?
Pulling on extended and pronated forearm
What happens in a pulled elbow?
Tearing of annular ligament
Radial head moves distally out of socket formed by annular ligament
Annular ligament becomes trapped between radial head and capitulum of humerus
How does a pulled elbow present?
Elbow is flexed
Forearm is pronated
What is olecranon bursitis?
Inflammation of the bursa in the elbow joint
Which bursae may become inflamed in olecranon bursitis?
Subcutaneous bursa
Subtendinous bursa
What causes inflammation of the subcutaneous bursa?
Repeated pressure and friction by falls on elbow
Infection by abrasions over elbow
What causes inflammation of the subtendinous bursa?
Excessive friction between triceps brachii tendon and olecranon
due to repeated flexion and extension of elbow
Which is more commonly inflamed - subcutaneous bursa or subtendinous bursa?
Subcutaneous bursa
When is olecranon bursitis more painful - flexed elbow or extended elbow? Why?
Flexed elbow
More pressure exerted on inflamed bursa
How is olecranon bursitis treated?
Compression bandaging
Aspiration
If infected - surgical drainage, washout, antibiotics
If chronic - hydrocortisone injections
What is a Colles’ fracture?
Type of fracture of the distal radius and ulna
What type of fracture does the distal radius show in a Colles’ fracture?
Transverse fracture
What type of fracture does the distal ulnae show in a Colles’ fracture?
Avulsion fracture of ulnar styloid process
What causes a Colles’ fracture? Give an example
Forced extension of wrist
e.g. falling on outstretched hand
How do the bone fragments displace in a Colles’ fracture?
Distal bony fragment of radius displaces dorsally
Why is there shortening of the forearm with a Colles’ fracture?
Distal fragment of radius overrides proximal fragment
How does a Colles’ fracture present?
Dinner fork deformity - abnormal curvature in distal posterior forearm
Do Colles’ fractures heal well or not? Why?
Yes they do
rich blood supply to distal radius
What is a complication of a Colles’ fracture in children?
Fracture may pass through epiphyseal plate of radius
may malalign during healing
disturbs growth of radius
What is a Smith’s fracture?
Type of fracture of distal radius and ulna
What causes a Smith’s fracture? Give an example
Forced flexion of wrist
e.g. falling onto a flexed wrist
How do the bone fragments displace in a Smith’s fracture?
Distal radius fragment displaces anteriorly
What causes a scaphoid fracture? Give an example
Hyperextension of wrist
e.g. falling onto an outstretched hand
How does a scaphoid fracture present?
Tenderness in anatomical snuffbox
When are scaphoid fractures visible on an X-ray?
Don’t show up immediately on X-ray
Take 10-14 days to show up
What is a complication of a scaphoid fracture?
Avascular necrosis of proximal bony fragment
Predisposes to wrist arthritis in later life
Why can avascular necrosis occur with a scaphoid fracture?
Because blood supply is distal to proximal
blood supply to proximal fragment is cut off
