Elbow Flashcards
What is the common mechanism for supracondular fractures of distal humerus?
Falling on outstretched hand with elbow hyperextended
How does a supracondular fracture of the distal elbow appear?
Extra-articular
Distal fragment displaced posteriorly
What are complications of supracondular distal humerus fractures?
Malunion
Damage to median nerve
Ischeamic contracture
How does ischeamic contracture occur?
Brachial artery damaged
Ischemia of muscles in anterior forearm
Oedema and compartment syndrome
In repair phase dead muscle replaced by fibrosis
Fibrotic tissue contracts resulting in flexion contracture
How does Volkmans ischeamic contracture appear?
Wrist flexed
Fingers extended at MCPJ and flexed at IPJ
Forearm pronated
Elbow flexed
How do elbow dislocations occur?
Fall onto outstretched hand with elbow partially flexed
Partially flexed as stability of joint here from ligaments instead of muscles
What is the most common type of elbow dislocation?
Posterior
Distal end of humerus driven though joint capsule anteriorly
Ulnar collateral ligament torn
What is pulled elbow?
Subluxation of the radial head
What is subluxation?
Partial disruption of a joint with some remaining but abnormal apposition of the articular surfaces
How is a pulled elbow caused?
Longitudinal traction with forearm pronated
How does pulled elbow present?
Reduced movement of elbow
Pain in lateral aspect of proximal forearm
How does pulled elbow occur?
In pronation as annular ligament more relaxed
Traction tears annular ligament from attachment of neck of radius
Radial head dismally though annular ligament
Why is pulled elbow more common in children?
Their annular ligament is still strengthening
How do radial head and neck fractures occur?
Fall on outstretched hand when radial head impacts on capitellum of humerus
How do radial head and neck fractures present?
Pain and loss of movement in lateral proximal part of forearm
Modest swelling
Fat pad on x-ray (effusion)
Why is OA of the elbow uncommon?
Due to well matched joint surfaces
Strong ligaments
How does OA of the elbow present?
Crepitus
Locking (loose cartilage fragments)
Swelling (effusion)
Osteophytes impinging on ulnar nerve
What is rheumatoid arthritis?
Autoantibodies attack synovial membranes
Inflamed synovial cells proliferate into pannus
Pannus penetrates though cartilage and bones leading to erosion and deformity
Can damge organs
How does rheumatoid arthritis appear on x-rays?
Joint space narrowing
Periarticular osteopenia
Juxta-articulation bony erosions
Subluxation
What is another name for lateral elbow tendinopathy and what is it?
Tennis elbow
Chronic overuse of these extensor tendons
Extensor carpi radialis brevis helps stabilise wrist but when overused is weakened and micro tears appear in tendon leading to inflammation
How does LET present?
Pain at common extensor origin
Lateral epicondyle pain when extending wrist
What is another name for medial elbow tendinopathy and what is it?
Golfer’s elbow
Pain at interface between pronator teres and flexor carpi radialis origins
At common flexor origin
When is pain present in MET?
With resisted flexion and pronation of wrist
What causes olecranon bursitis?
Repeated micro trauma (eg, leaning elbows on desk
Serous fluid accumulates and causes soft cyst
What causes rheumatoid nodules?
Extra-articular manifestation of RhA
More common in smokers
Over areas that have repeated micro trauma
What are gouty tophi?
Modular masses of mono sodium urate crystals deposited in soft tissues
Due to untreated gout
Where are gouty tophi seen?
Olecranon bursa
Fingers
Subcutaneous tissue of elbow
What is cubital tunnel syndrome?
Compression of the ulnar nerve in the cubital tunnel
What causes cubital tunnel syndrome?
When the ulnar nerve passes between the tendinous arch created by the 2 heads of the flexor carpi ulnaris and becomes impinged
How does micro trauma cause cubital tunnel syndrome and how does it present?
Banging elbow
Sharp pain radiating from elbow to cutaneous ulnar nerve territory
How does compression of ulnar nerve cause cubital tunnel syndrome and how does it present?
Paraesthesia in cutaneous territory
Weakness in muscles supplied by ulnar nerve
