1. Elbow clinical conditions

Question 1

When does supracondylar fracture of humerus commonly occur?

Answer 1

FOOSH in children

Question 2

Which X-ray signs indicate supracondylar fracture of humerus?

Answer 2

1- raised anterior and posterior fat pads (joint effusion - intracapsular fracture)
2- <1/3 of humerus capitulum lies in front of anterior humeral line

Question 3

In which direction does the distal fragment in a supracondylar fracture of humerus displace?

Answer 3

posteriorly due to pull of triceps muscle

Question 4

Which neurovascular structures can be damaged in a supracondlar fracture of humerus?

Answer 4

1- brachial artery - can be torn or entraped

2- median, ulnar or radial nerves - compression/damage

Question 5

What can damage to the brachial artery at the elbow result in?

Answer 5

volkmann’s contracture: uncontrolled flexion of hand as ischaemia causes flexor muscles to become short and fibrotic

Question 6

What are radial head/neck fractures commonly caused by?

Answer 6

FOOSH in adults

Question 7

Which X-ray signs indicate radial head/neck fractures?

Answer 7

raised anterior and posterior fat pads

Question 8

In which direction do elbow dislocations usually occur?

Answer 8

posterior: distal end of humerus driven through weak anterior part of joint capsule as radius and ulna dislocation posteriorly

Question 9

Name 2 structures that might be damaged in a posterior elbow dislocation.

Answer 9

1- ulnar n.

2- ulnar collateral ligament

Question 10

What is the medical name of a “pulled elbow”?

Answer 10

subluxation and dislocation of radial head

Question 11

How does a pulled elbow occur?

Answer 11

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)

Question 12

What causes pain in a pulled elbow?

Answer 12

proximal part of torn anular ligament may become trapped between head of radius and humerus capitulum

Question 13

Why is a pulled elbow more common in children?

Answer 13

anular ligament is weaker and more easily torn, and bones are smaller

Question 14

What is “tennis elbow”?

Answer 14

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

Question 15

What is “golfer’s elbow”?

Answer 15

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

Question 16

Is lateral or medial epicondylitis more common?

Answer 16

lateral 10x more common

Question 17

Name 3 possible causes of swelling around the elbow.

Answer 17

1. olecranon bursitis
2. gouty tophi
3. rheumatoid arthritis nodules

Question 18

What is subcutaneous bursitis? How is it caused?

Answer 18

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)

Question 19

What is subtendinous bursitis? How is it caused?

Answer 19

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)

Question 20

What causes gouti tophi?

Answer 20

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)

Question 21

what is the most common fracture in >50yo?

Answer 21

fracture of distal radius

Question 22

why does fracture of one forearm bone often result in fracture of the other?

Answer 22

shafts are firmly bound together by interosseus membrane

Question 23

what are the 2 types of distal radius fracture and how are they different?

Answer 23

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

Question 24

Which type of fracture causes pain in the anatomical snuffbox?

Answer 24

scaphoid

Question 25

why should 2 X-rays be performed 10 days apart on suspected scaphoid fractures?

Answer 25

initial wrist X-ray may not reveal fracture but bone resorption may reveal fracture line 10 days later

Question 26

why do scaphoid fractures need to be quickly reduced?

Answer 26

risk of avascular necrosis of proximal scaphoid fragment which can then lead to wrist OA

Question 27

describe the blood supply to the scaphoid

Answer 27

lateral and distal branches of radial artery provide abundant supply to middle and distal scaphoid but neglect proximal portion, which relies on retrograde flow