FRACTURE OF OLECRANON
Olecranon fractures are caused by a direct blow to the elbow or an indirect avulsion injury, such as a fall on an outstretched hand while the triceps is contracting. Nondisplaced fractures of the olecranon can be treated with posterior splinting or a cast, but displaced fractures are best stabilized with open reduction and internal fixation.
These fractures are typically intra-articular; therefore, care should be taken to appropriately reduce and align the joint surface during surgical fixation, regardless of technique utilized. Fixation with a tension band wire using screws or Kirschner wires is common in more simple fracture patterns. The tension band technique acts to convert the tensile forces through the fracture that are causing displacement into compressive forces that will allow fracture reduction and healing. If the fracture is too comminuted or too distal (extends to the coronoid or proximal ulnar shaft), a tension band technique is typically not adequate for fracture stability. Interfragmentary compression utilizing plate fixation is the preferred method of treatment in this situation. Precontoured plates that match the anatomy of the olecranon are now available and routinely used. The plate is positioned along the subcutaneous border of the ulna, however, and may require removal after fracture healing owing to its very superficial location.
Excision of the olecranon and triceps repair is an alternative method of treating isolated, displaced fractures if the coronoid process, collateral ligaments, and anterior soft tissues remain intact. Typically, this procedure is considered in extra-articular fractures or in fractures that are too comminuted to be stably fixed. The triceps brachii tendon covers the posterior aspect of the joint capsule before it attaches to the olecranon, and a broad expanse of the aponeurosis of the triceps brachii muscle joins the deep fascia of the forearm distal to the elbow. This expanse ensures good posterior stability of the elbow joint after olecranon excision. Up to 70% of the olecranon can be excised without resultant instability if the collateral ligaments are intact. Because the triceps brachii muscle is a primary extensor of the forearm, it must be accurately reattached to the distal fragment of the ulna after the olecranon is excised to maintain adequate elbow extension.