Imaging Studies
Most radial head injuries can be assessed adequately with standard plain radiography of the elbow. Normal radiographic examination findings demonstrate that the radial head is aligned with the capitellum on all views. A dislocation of the radial head can be easily missed if all radiographs are not carefully examined for this relation. For the normal elbow, a line drawn through the radial head and shaft should always line up with the capitellum, and with a supinated lateral view, lines drawn tangential to the head anteriorly and posteriorly should enclose the capitellum.
With a radial head dislocation, these radiographic findings are disrupted. The images below are examples of an injury that appears to be a simple ulna fracture when only the anteroposterior (AP) view is evaluated but that clearly has a dislocated radial head on the lateral view. As with any fracture assessment, two views perpendicular to each other are always required.
The radial head must be aligned with the capitellum on all views. Simple ulna fracture on anteroposterior view; radial head appears in place but see Image below.
The radial head must be aligned with the capitellum on all views. Dislocated radial head is observed on the lateral radiograph.
In rare circumstances, computed tomography (CT) of the elbow is useful to define fracture patterns.
Joint Aspiration and Injection
Most radial head fractures and dislocations are well defined by the findings on clinical examination and imaging studies. If a high index of suspicion exists for an occult fracture, the joint can be aspirated. Fat globules in the fluid imply a fracture. If suspicious wounds are present and an open fracture or dislocation is suspected, the joint can be injected. If fluid comes out of the wound, then the wound is communicating with the joint.
-
Congenital radial head dislocation.
-
The radial head must be aligned with the capitellum on all views. Simple ulna fracture on anteroposterior view; radial head appears in place but see Image below.
-
The radial head must be aligned with the capitellum on all views. Dislocated radial head is observed on the lateral radiograph.
-
Soft tissue injury. Soft tissues are as important as bone in determining functional outcome.
-
Isolated radial head dislocation is almost always treated closed.
-
Minimally displaced radial head/neck fractures can be treated with early motion.
-
Floating elbow. Combined Monteggia fracture with dislocation and supracondylar humerus fractures. Treatment of a floating elbow requires fixation of both fractures.
-
Displaced radial head fracture.
-
Radial head fracture fixation.
-
Radial head fracture in a child.
-
Radial head fracture in a child.
-
Radial head replacement, Monteggia variant and the radial head could not be salvaged.
-
Radial head replacement, temporary spacer.
-
Radial head excessive excision. Do not excise distal to the annular ligament because the forearm becomes unstable.
-
Radial head replacement, salvage with radial head spacer.
-
Unsuccessful open reduction of Monteggia fracture-dislocation.
-
Displaced radial head fracture.
-
Fixation with hardware pain.
-
Same patient as in Image above. Pain was resolved after hardware removal.
-
Synostosis after Monteggia fracture-dislocation; see Image below.
-
Improved motion after synostosis resection.
-
Monteggia variant with radial head fracture.
-
Fixation of both radial head and ulna.
Tables
Type |
Description |
Equivalent(s) |
% |
Type I |
Anterior dislocation of the radial head and anterior angulation of the ulna fracture |
Radial head or neck fracture instead of dislocation |
60 |
Type II |
Posterior dislocation of the radial head and posterior angulation of the ulna fracture |
Posterior elbow dislocation Radial head or neck fracture instead of dislocation |
105 |
Type III |
Lateral dislocation of the radial head with proximal ulna fracture |
Radial head or neck fracture instead of dislocation |
20 |
Type IV |
Anterior dislocation of the radial head and proximal shafts of both bones fractured at same level |
Radial head or neck fracture instead of dislocation |
5 |
