Flashcards in 1. Elbow clinical conditions Deck (27)
When does supracondylar fracture of humerus commonly occur?
FOOSH in children
Which X-ray signs indicate supracondylar fracture of humerus?
1- raised anterior and posterior fat pads (joint effusion - intracapsular fracture)
2- <1/3 of humerus capitulum lies in front of anterior humeral line
In which direction does the distal fragment in a supracondylar fracture of humerus displace?
posteriorly due to pull of triceps muscle
Which neurovascular structures can be damaged in a supracondlar fracture of humerus?
1- brachial artery - can be torn or entraped
2- median, ulnar or radial nerves - compression/damage
What can damage to the brachial artery at the elbow result in?
volkmann's contracture: uncontrolled flexion of hand as ischaemia causes flexor muscles to become short and fibrotic
What are radial head/neck fractures commonly caused by?
FOOSH in adults
Which X-ray signs indicate radial head/neck fractures?
raised anterior and posterior fat pads
In which direction do elbow dislocations usually occur?
posterior: distal end of humerus driven through weak anterior part of joint capsule as radius and ulna dislocation posteriorly
Name 2 structures that might be damaged in a posterior elbow dislocation.
1- ulnar n.
2- ulnar collateral ligament
What is the medical name of a "pulled elbow"?
subluxation and dislocation of radial head
How does a pulled elbow occur?
i. sudden pulling of upper limb when forearm is pronated...
ii. tears distal attachment of anular ligament (where it is loosely attached to neck of radius)...
iii. radial head slips out of anular ligament (subluxation)...
iv. muscle (e.g. supinator) action pulls radial head superiorly (dislocation)
What causes pain in a pulled elbow?
proximal part of torn anular ligament may become trapped between head of radius and humerus capitulum
Why is a pulled elbow more common in children?
anular ligament is weaker and more easily torn, and bones are smaller
What is "tennis elbow"?
lateral epicondylitis: repeated forceful flexion and extension of wrist... strains attachment of common extensor tendon... inflammation of periosteum of lateral epicondyle... pain over lateral epicondyle that radiates down posterior surface of forearm
What is "golfer's elbow"?
Medial epicondylitis: repeated forceful flexion and extension of wrist... strains attachment of common flexor tendon... inflammation of periosteum of medial epicondyle... pain over medial epicondyle
Is lateral or medial epicondylitis more common?
lateral 10x more common
Name 3 possible causes of swelling around the elbow.
1. olecranon bursitis
2. gouty tophi
3. rheumatoid arthritis nodules
What is subcutaneous bursitis? How is it caused?
inflammation and swelling of subcutaneous olecranon bursa (between skin and olecranon process of ulna) usually due to repeated minor trauma (contents is just serous fluid)
What is subtendinous bursitis? How is it caused?
inflammation and swelling of subtendinous olecranon bursa (between triceps brachii tendon and olecranon process of ulna) caused by repeated flexion and extension of forearm (flexion usually more painful as puts more pressure on bursa)
What causes gouti tophi?
disorders of nucleic acid metabolism (i.e. gout) leading to hyperuricaemia and sodium urate crystal deposition in the joints (causing recurrent attacks of arthritis) and soft tissues (ear, elbow and Achilles tendon)
what is the most common fracture in >50yo?
fracture of distal radius
why does fracture of one forearm bone often result in fracture of the other?
shafts are firmly bound together by interosseus membrane
what are the 2 types of distal radius fracture and how are they different?
1. Colles' fracture
- caused by FOOSH - forced dorsiflexion of the hand
- distal fragment of radius (often comminuted) is displaced dorsally/posteriorly: 'dinner fork deformity'
- ulnar styloid process is often avulsed
2. Smith's fracture
- caused by falling onto back of hand - forced palmarflexion of hand
- distal fragment is displaced anteriorly
Which type of fracture causes pain in the anatomical snuffbox?
why should 2 X-rays be performed 10 days apart on suspected scaphoid fractures?
initial wrist X-ray may not reveal fracture but bone resorption may reveal fracture line 10 days later
why do scaphoid fractures need to be quickly reduced?
risk of avascular necrosis of proximal scaphoid fragment which can then lead to wrist OA