A RARE PRESENTATION OF IRREDUCIBLE POSTERIOR DISLOCATION OF ELBOW - RADIAL HEAD INTERPOSITION

Abstract

ABSTRACT A case of irreducible dislocation
of elbow with fractured radial neck
(Mason type-IV) is described for its unusual
presentation. A 56 year old lady
from a remote rural area in Tamil nadu,
India came to the outpatient clinic two
weeks after trauma with pain, swelling
and restricted dynamic deformity of the
right elbow without any neurological deficit.
In the immediate aftermath of trauma
she had native treatment. The Radial
head was found displaced into olecranon
fossa and was preventing closed reduction.
This was managed surgically by removal
of radial head, closed reduction
and k wire stabilization through a small
posterior incision. This case is presented
due to its rarity -only two cases has been
reported so far in the literature. The rarity
may be ascribed to the usual mechanism
- the postero-lateral rotatory mechanism,
which forces the radial head onto
the capitellum, causing a
fracture at the radial neck and the elbow
dislocates posteriorly leaving the head anterior
to or below the humerus. Thus radial
head reaching the olecranon fossa cannot
be explained this mechanism alone. The
probable explanation in this case may be
1) The radial neck was fractured incompletely
dragging the radial head along with
it and the radial head may have got separated
and stuck in the olecranon fossa on
further manipulation. 2) Axial force on a
flexed elbow could have caused the head
fragment to displace posteriorly- but this is
rare. 3) The radial neck could have got
fractured entirely after the initial trauma
due to the manipulation by traditional bone
setters.