Review Question - QID 9113

This patient has sustained a fracture of the anteromedial coronoid. These fractures may not be readily visible on radiography, therefore CT scan is the next best step.

The coronoid process is one of the main constraints providing ulnohumeral joint stability. The coronoid process and the radial head provide a buttress against posterior displacement of the elbow joint. Fracture of the coronoid process can be either an isolated finding following elbow dislocation or part of a more complex fracture-dislocation. This patient had a fracture to the of the anteromedial portion of the coronoid, therefore the medial side of the elbow is unsupported to varus stresses. As a result, the joint line will narrow from lateral to medial secondary to medial collapse of the joint. On a lateral, the crescent sign, which represents the depressed anteromedial facet of the coronoid, may be seen.

Steinman et al. report that with an anteromedial coronoid fracture, the anteroposterior radiograph of the elbow will demonstrate progressive narrowing of the joint space from lateral to medial between the medial trochlea and the coronoid process. On a lateral radiograph, a coronoid fracture fragment may appear small and may be confused with a radial head fracture. A CT scan of the elbow is recommended in all cases of suspected coronoid fractures because such a fracture is readily seen with this imaging modality.

Doornberg et al. report that coronoid fractures are associated with specific patterns of traumatic elbow instability. They concluded that large coronoid fractures were associated with anterior and posterior olecranon fracture-dislocations while small transverse fractures were associated with terrible triad injuries. Finally, anteromedial facet fractures were associated with varus posteromedial rotational instability.

Ring et al. wrote a surgical technique of repairing the anteromedial facet fracture. They report that fractures of the anteromedial facet of the coronoid may be treated with a plate, a screw, or sutures. They conclude that secure fixation of this fragment usually restores good elbow function.

Figure A demonstrates fat pads both anteriorly and posteriorly indicating likely intraarticular pathology. Illustrations A and B are axial and sagittal CT cuts, respectively, from the same patient demonstrating a coronoid fracture. Illustration C demonstrates the crescent sign. Illustration D is a CT image demonstrating depression of the medial coronoid with incongruity of the ulnohumeral joint.

Incorrect Answers:
Answer 2: Though an examination of the elbow may reveal instability, a CT scan is the next best option.
Answer 3: The Greenspan view, or radiocapitllar radiograph is used to visualize the radiocapitellar joint and assess the radial head.
Answer 4: Physical therapy and range of motion exercises are not appropriate at this time as the patient has some degree of elbow instability.
Answer 5: This is the treatment for terrible triad injury of the elbow.