Conditions Of The Elbow Flashcards
What is the most common mechanism of a supracondylar fracture of the distal humerus? 1️⃣
-FOOSH from a moderate height (with hyperextended elbows)
E.g child falling off monkey bars
[less common mechanism is falling onto a flexed elbow. ‘Flexion supracondylar fractures’ occur most often in the elderly]
In what patient group are supracondylar fractures of the distal humerus most common seen in? 1️⃣
90% seen in children <10yrs. Peak of 5-7yrs. Occur most commonly in boys
How does a child with a supracondylar fracture of the distal humerus present? 1️⃣
- pain
- deformity
- loss of function
How do supracondylar fractures usually look on an X-ray? 1️⃣
-fracture line is usually extra-articular (joint not involved) and distal fragment usually displaced posteriorly
State 3 main complications of supracondylar fractures of the distal humerus 1️⃣
- malunion, resulting in cubits varus. ‘Gunstock deformity’
- nerve damage to median nerve, radial nerve or ulnar nerve
- ischaemic contracture
How can supracondylar fractures of the distal humerus result in ischaemia of muscles? 1️⃣
- brachial artery passes very close to the fracture site
- can be damaged or occluded by a displaced fracture
-if reflex spasm of the collateral circulation around the elbow also occurs, there will be ischaemia of the muscles in the anterior compartment of the forearm
What does ischaemia of the muscles in the anterior forearm result in? 1️⃣
- oedema
- rise in compartment pressure (compartment syndrome)
-> further exacerbated the ischaemia as it impedes arterial inflow, and if untreated, the muscle bellies undergo infarction
How does Volkmann’s ischaemic contracture arise? 1️⃣
- during repair phase following infarction, dead muscle tissue is replaced by scar tissue through fibrosis
- fibrotic tissue contracts, eventually resulting in a flexion contracture
Describe the appearance of the Volkmann’s ischaemic contracture 1️⃣
- wrist typically flexed
- fingers extended at MCPJs
- fingers flexed at IPJs
- forearm pronated
- elbow flexed
What should be done in order to minimise the risk of the complications of supracondylar fractures of the distal humerus? 1️⃣
- prompt neurovascular examination conducted
- if any compromise then emergency reduction and fixation of the fracture is required
When does elbow dislocation usually occur? 2️⃣
-when a person, often a child, FOOSH with elbows partially flexed
Most common joint to dislocate in children and second most in adults (after shoulder) due to high frequency of FOOSH
Why is the elbow dislocation most likely to occur in mid-flexion? 2️⃣
- the configuration of the bones contributes most to stability of the elbow in full extension
- the stability of the elbow in mid flexion is more reliant on the ligaments
What type of elbow dislocation is most common? 2️⃣
Posterior elbow dislocation 90% cases
- distal end of the humerus is driven through the joint capsule anteriorly
- the ulnar collateral ligament is usually torn and there can be associated fracture and/or ulnar nerve involvement
What are anterior (10% cases) usually the result of? 2️⃣
-a direct blow to the posterior aspect of a flexed elbow
Associated fractures of the olecranon are commonly seen due to high degree of force required
What is a pulled elbow? (‘Nursemaids elbow’) 3️⃣
Subluxation of the radial head
(Subluxation= partial disruption of a joint with some remaining but abnormal apposition of the articular surfaces. I.e. an incomplete dislocation)
In what patient group does a pulled elbow commonly occur? 3️⃣
Children 2-5yrs
How does a child with a pulled elbow present? 3️⃣
- with reduced movement of the elbow
- pain over the lateral aspect of the proximal forearm
- parent often states that there are ‘not using their arm’
What is the classical described mechanism of injury for a pulled elbow? 3️⃣
-when longitudinal traction is applied to the arm with the forearm pronated
E.g tugging an uncooperative child or swinging a child by their arms
Other mechanisms include falls or overreaching for an object
Why does a pulled elbow injury most commonly occur in pronation? 3️⃣
- annular ligament is taut in supination and more relaxed in pronation so easier for subluxation to occur
- longitudinal traction on the radial head tears the distal attachment of the annular ligament from where it is loosely attached to the neck of the radius
- radial head is then displaced distally through the torn ligament
(Annular ligament strengthens as child ages)
What do radial head and neck fractures usually result from? 4️⃣
FOOSH when radial head impacts on the capitellum of the humerus
Commonest type of elbow fracture in adults
How does a patient with radial head and neck fractures present? 4️⃣
- pain in lateral aspect of proximal forearm
- loss of range of movement
- swelling
How does the fracture appear on an X ray? 4️⃣
-often quite difficult to see
-‘fat pad sign’ (‘sail sign’) indicates that an effusion is present
Trauma likely to be due to a haemarthrosis secondary to an intra-articular fracture. The sign is caused by displacement of the anterior fat pad which appears black as it is relatively radio-lucent
Why is OA of the elbow relatively uncommon? 5️⃣
Because of the well-matched joint surfaces and strong stabilising ligaments
Therefore it can tolerate large forces without becoming unstable. So there is leads wear and tear with age
In what patient groups is OA of the elbow commonly seen? 5️⃣
- men than women
- manual workers and athletes who engage in sports involving throwing
What do patients with elbow OA usually report? 5️⃣
- crepitus
- locking (caused by loose fragments of cartilage)
- swelling occurs relatively late and is due to an effusion
- osteophytes can impinge on the ulnar nerve, causing paraesthesia and or muscle weakness.
- stiffness
- loss of extension
