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:
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,
despit negative x rays, and arrange for followup, with re-
evaluation 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
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.
