9.18 Radial Head Fracture
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agk's Library of Common Simple Emergencies

Presentation
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A patient has fallen on an outstretched hand 
and has a normal non-painful shoulder, wrist, 
and hand, but pain in the elbow joint. The 
joint may be intact, with full range of 
flexion, but there is pain or decreased range 
of motion on extension, supination and 
pronation. Tenderness is greatest over the 
radial head and lateral condyle. X-rays may 
show a fracture or dislocation of the head of 
the radius. In all views, a line down the 
center of the radius should point to the 
capitellum of the lateral condyle. Often, 
however, no fracture is visible, and the only 
x-ray signs are of the elbow effusion or 
hemarthrosis pushing the posterior fat pad out 
of the olecranon fossa and the anterior fat pad 
out of its normal position on the lateral view.

What to do:
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- Obtain a detailed history of the mechanism of 
    injury, and a physical examination, looking 
    for the features described above, and x-
    rays of the elbow, looking for visible fat 
    pads as well as fracture lines.
- If there is any question of a radial head 
    fracture, immobilize the elbow (preventing 
    pronation and supination of the hand) with 
    a gutter splint extending from proximal 
    humerus to hand, or sugar tong splints, or 
    simply a sling, for the next week.
- Explain to the patient the possibility of a 
    fracture, despite negative x-rays, and 
    arrange for followup, with reevaluation and 
    repeat films in 1-2 weeks.

What not to do:
---------------

Do not jump to the diagnosis of "tennis elbow" 
or "sprained elbow" simply on the basis of a 
negative x-ray.

Discussion
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Small, non-displaced fractures of the radial 
head may show up on x-rays weeks later or never 
at all. Because pronation and supination of the 
hand are achieved by rotating the radial head 
upon the capitellum of the humerus, very small 
imperfections in healing of the radial head may 
produce enormous impairment of hand function, 
which may be only partly improved by surgical 
excision of the radial head. Immobilization at 
the first question of a radial head fracture 
may help preserve essential pronation and 
supination. "Tennis elbow" is a tenosynovitis 
of the common insertion of the wrist extensors 
upon the lateral condyle, and results in pain 
on wrist extension rather than on pronation and 
supination.

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 from Buttaravoli & Stair: COMMON SIMPLE EMERGENCIES
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