An Elbow dislocation occurs when the radius and ulna bones
of the forearm move out of place from the humerus bone of the upper arm. There
are two basic types of elbow dislocations:
Simple
No fracture of the bones around the elbow joint
Usually ligamentous injury
Complex
Fracture has occurred along with ligamentous injury
Simple elbow dislocations typically occur when the patient
falls onto an outstretched hand. Injury progression from lateral to medial in
most patients. Posterolateral simple dislocations are the most common, occurring
approximately 90% of the time.
The proximal ulna and radius are displaced
posterolaterally relative to the distal humerus. Postemedial dislocations occur
at the proximal ulna and radius and are displaced posteromedially relative to
the distal humerus. In medial dislocations, the proximal ulna and radius are
displaced medially relative to the distal humerus. With lateral dislocations,
the proximal ulna and radius are displaced laterally relative to the distal
humerus. Anterior dislocations are rare, as they result from a direct force
applied to the posterior aspect of the forearm with the elbow in a flexed
position. Anterior dislocations occur when the proximal ulna and radius are
displaced anteriorly relative to the distal humerus. If stable, simple acute
fractures can be treated with a closed reduction and a splint for two to three
days (no more than two weeks) in addition to range-of-motion exercises and
physical therapy. Unstable simple fractures are rare, but can be stabilized by
ligament repair and/or by the use of an external fixator or cross pinning of
the joint in the elderly.
Chronic Elbow dislocations will need to be treated with an
open reduction and external fixator and is usually hinged. Recurrent elbow
dislocations (diagnosed by pivot shift) occurs due to a deficiency of the
lateral collateral ligament and is treated by a reconstruction of the
ulnohumeral ligament with a tendon graft.
