Tuesday, October 30, 2018

Olecranon Fractures


Fractures of the olecranon may occur due to a direct blow to the elbow or from a fall onto an outstretched hand. Nondisplaced fractures have less than 2mm of separation and are considered stable. Fracture separation will not increase with elbow flexion. Extensor mechanism is intact and the patient will be able to extend the elbow against gravity. Displaced fractures could be an avulsion, oblique, transverse, comminuted, or dislocated.
Olecranon fracture dislocations can be anterior (transolecranon) or posterior (similar to monteggia fracture dislocation). An examination will show that the patient is unable to extend the elbow with these displaced fracture types. A true lateral view x-ray will clearly show the olecranon fracture. Usually, these fractures are followed by stiffness of the elbow in about 50% of the patients. However, this does not affect the function.
The goal of treatment for olecranon fractures should be restoration of the articular surface, preservation of the continuity of extensor mechanisms, maintain elbow stability, and avoid stiffness of the elbow. Nonoperative treatment is used for nondisplaced fractures and it may be used for some displaced fractures in elderly patients (treat elbow in some flexion with a splint). I would personally use minimally invasive techniques in these patients unless the skin is very bad, or the fracture is very comminuted.
There are three techniques used for surgical treatment: the tension band technique, detach olecranon and reattach triceps, and plate and screw fixation. The tension band technique is only used for transverse fractures with no comminution. K-wires and screws are used, and the surgeon may use either a 6.5mm screw or Kwires for the tension band. When doing the tension band technique, you want to engage the anterior cortex of the ulna. The surgeon should avoid over penetration to avoid affecting the forearm rotation or injuring the anterior interosseous nerve. The surgeon needs to be sure that the pins are not fixing the radius and that after the operation, the patient can perform pronation and supination of the forearm (pull the pins out slightly if needed). The distractive force of the triceps is converted to compression force at the articular surgace, especially when bending the elbow. The drill hole for the K-wire should be positioned about 4-5cm from the fracture which gives enough safe distance so that the fracture will not propagate. Place the tension band wire through the drilled holes before application of the K wires. The surgeon should be sure that the hook to the K-wire is posterior. Make sure that the tension band wire is close to the bone so there is no laxity in the fixation and instability. An intramedullary screw could be used. This screw fixation may need a washer to capture the tension band wire. Intramedullary 6.5mm screw fixation is a reasonable option for fixation but it may need to be supplemented with tension band wires. Never use cancellous screw alone. The tension band technique are for transverse fractures of the olecranon. If fractures comminution is present, change the plan of fixation.

When detaching the olecranon and reattaching the triceps, an excision of the fracture fragment and triceps advancement is used:

  • If the fracture is less than 50%
  • To treat elderly patients (especially if fracture is comminuted)
  • For some nonunions when the fracture is small and cannot be fixed

The surgeon must be sure that the procedure is done with the elbow is stable. If the elbow has ligamentous instability and excision of the fracture fragment is done, this will make the elbow very unstable. The triceps should be attached closer to the articular surface.
Special olecranon plates are available when using a plate and screw fixation technique. The bridge plate and screw fixation technique is used in comminuted, Monteggia, oblique fractures extending to the coranoid, and fracture dislocation. The plate is placed on the tension side of the olecranon (dorsal side). Sometimes, an opening is made through the triceps and the plate is placed against the bone, then suturing the triceps tendon over the plate to avoid hardware prominence.
In summary, if the patient is elderly with a small, comminuted fracture fragment less than 50% of the joint space, excise the fragment, and reattach the triceps tendon to the olecranon. If the olecranon fracture is transverse and proximal to the base of the coranoid process, then use the tension band technique. Use plate fixation for all olecranon fracture scenerios, such comminuted fractures, oblique fractures, unstable fractures, dislocation, or fractures distal to the coranoid process. The typical exam question scenario will discuss a comminuted fracture that should be treated with a plate. You probably need to remove above 20% of the plate fixations due to hardware irritation. Hardware irritation is worse with the tension band surgical treatment (may need to remove in more than 50% of cases).