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.
