Review Question - QID 5822

A lateral extensile approach is preferred for exposure and surgical fixation of coronal shear capitellum fractures.

A lateral extensile approach allows for visualization of capitellum and trochlea proximally, as well as radial head and neck pathology distally. These structures can be approached by developing the interval between the triceps muscle posteriorly, and the brachioradialis and extensor carpi radialis longus anteriorly. The dissection may be continued distally between the extensor carpi ulnaris and the anconeus muscles to access the radial head and neck.

Ruchelsman et al. reviewed coronal shear capitellum fractures. They state that the forearm should be pronated to move the radial nerve away from the surgical field during the lateral extensile approach. In this approach, the common origin of the radial wrist extensors, with the anterior capsule, should be sharply elevated as a full-thickness sleeve from the lateral supracondylar ridge.

McKee et al. identified a unique shear fracture pattern of the distal articular surface of the humerus in six patients that involved the capitellum and a portion of the trochlea. They termed this injury as the 'double-arc sign', based on a characteristic lateral radiographic abnormality seen with this fracture pattern. This injury pattern is also called the McKee modification (Type IV) of the Bryan and Morrey Classification of capitellum fractures.

Illustration A shows the "double arc sign" as described originally by Dr McKee. Illustration B shows the lateral extensile approach to the elbow with an illustration (left) and cadaveric (right) labeled image.

Incorrect Answers:
Answer 1: Extra-articular distal humerus fractures with metaphyseal comminution would be best approached with a posterior incision and triceps splitting or sparing deep dissection.
Answer 2: Highly comminuted, proximal third radial shaft fracture would be best approached with a volar or dorsal approach to the forearm (e.g., Henry or Thompson approach).
Answer 3: Undisplaced, simple radial head fracture should be treated non-operatively.
Answer 5: Transolecranon anterior fracture-dislocations are best treated with a posterior approach to the elbow. Associated fractures can be reduced and fixed by working through the olecranon fracture.