Olecrenon fractures

From Medical-Wiki

The proximal bony projection of the ulna at the elbow is the olecranon. Taken together with the proximal portion of the coronoid process, the olecranon forms the notch of the ulna, a deep depression that is joined with the trochlea. The allows motion only in an anteroposterior plane—providing great stability to the joint. [1]

The olecranon is a very heavy and strong structure, but it is fractured rather frequently in adults because of its prominent position on the point of the elbow. In addition, tremendous cross strain is imparted to the olecranon during falls on a flexed forearm. Children do not often experience olecranon fractures because in childhood, it is stronger than the lower end of the humerus.

The most common injury producing an olecranon fracture is a fall on a semiflexed supinated forearm. Muscles are tensed to protect against the fall, and as the hand hits the ground, the triceps muscle basically snaps the olecranon over the lower end of the humerus. Direct trauma to the point of the elbow and hyperextension can also produce fractures. Displacement of fracture fragments greater than 1.5 cm is uncommon. [2]

All fractures of the olecranon have some sort of intra-articular component. Because of this, they are usually accompanied by a hemarthrosis. This creates pain and swelling over the olecranon as well as an inability to extend the elbow against gravity. This is an indication of discontinuity of the triceps attachment. Presence or absence of this sign determines the course of treatment. [3]

Even though most olecranon fractures are isolated, careful examination of the shoulder, forearm, clavicle, humerus, wrist and hand are crucial to rule out other concomitant injuries. This is particularly true in patients who have multiple injuries—as in auto accident patients. The neuro-vascular integrity of the extremity including radial and ulnar pulses, as well as function of the ulnar, median, and posterior interosseous nerves should be established.

A typical fracture is a transverse or slightly oblique break near the olecranon base. The oblique fracture line slopes down and posteriorly. Sometimes, a small piece of bone may have been pulled off.

There are a number of classification systems. Perhaps the most straight-forward is that used by the Orthopedic Trauma Association. This divides fractures into three categories, Type A—extra-articular, type B—intra-articular, and type C—intra-articular fractures of both the radial head and olecranon.

Normal anteroposterior and lateral x-rays of the elbow are usually adequate for evaluating isolated olecranon fractures. The radiocapitellar view may be helpful for associated fractures of the radial head and capitellum.

Any patient with significant medical problems should have an olecranon fracture treated in a closed, conservative fashion. In patients with severe medical illness, steroid use, or dementia, even significantly displaced fractures can be treated non-surgically. The only treatment necessary is an Ace wrap with abundant padding. Extensor function may be compromised, but pain from non-union is rare.

In healthy patients, nondisplaced fractures with normal extensor function may be treated nonoperatively. Three weeks of casting is an average length of time. It is most convenient to immobilize the elbow at 90 degrees, but the elbow can be placed in any amount of flexion. Extension is often required for a reduction of displacement.

Significant displacement of greater than 2 mm or comminution sometimes require surgical intervention. Open reduction and internal fixation is the standard of care for displaced intra-articular fractures. [4]