Olecranon fractures range from simple nondisplaced fractures to complex fracture-dislocations of the elbow joint. Olecranon fracture is common occurrence because of its exposed position of olecranon on the point of the elbow. The injury is less common in children.
Olecranon fracture or olecranon process is fracture of fracture of large curved eminence called olecranon process that formes uppermost posterior aspect of ulna.
The olecranon process lies beneath the skin and it is very vulnerable to direct trauma.
Together with coronoid process, the olecranon forms the articular surface for articulation with the trochlea. This articulation allows movement only in anteroposterior plane.
Relevant Anatomy of Elbow and Olecranon Process
The elbow is a hinge joint formed by distal humerus, proximal radius and proximal ulna.
The olecranon is proximal part of the ulna that cups the end of the humerus and forms greater posterior part of trochlear notch. Trochlear notch is a a concave shaped structure which participates in trochleohumeral joint and is responsible for flexion-extension movements of the elbow. Anteriorly, the trochlear notch is completed by coronoid process, another process of ulna.
The radial head moves around the distal humerus and also rotates when the wrist is turned up and down.
The elbow is held together by ligaments, muscles and shape of the participating bones.
The elbow is a complex hinge joint. The major stabilizers to valgus are the medial (ulnar) collateral ligament and the radial head. The major stabilizer to varus stress is the lateral collateral ligament complex. The coronoid process stabilizes the humerus against the distal ulna.
Olecranon also prevents anterior translation of the ulna with respect to the distal humerus. The anterior surface of the olecranon is covered with articular cartilage. Therefore, all fractures except the rare tip fractures are intra-articular fractures. The triceps inserts into the posterior third of the olecranon and proximal ulna. The periosteum of the olecranon blends with the triceps.
Fracture displacement is largely due to the pull of the triceps. Usually, wide separation of fragments indicates an extensive tearing of the fibrous sheath in which the unopposed triceps is contracted, drawing the separated fragment upward.
Cause of Olecranon Fractures
The most common mechanism of an olecranon fracture is a fall on the semiflexed supinated forearm. Tense triceps snaps the olecranon over the lower end of the humerus, which acts as a fulcrum. A fall on the elbow or direct blow to elbow could also result in olecranon fracture.
Hperextension injuries of elbow, forceful throws are less common causes of olecranon fractures.
Stress fractures have also been reported.
Presentation of Olecranon Fracture
Pain and swelling of the elbow are major complaints. Gross disability can be noted in displaced fractures.
On examination, elbow is swollen and there is tenderness over the olecranon area. Mobility of the fragment may be noted. Patient would be unable to extend the elbow or it is painful in case of undisplaced fractures.
Elbow and the limb should be examined for associated injuries. Olecranon injury may be part of polytrauma and patient should be assessed for other injuries in other regions as well.
Extensor mechanism should be examined [ability to extend elbow].
Olecranon fracture is best visualized in lateral view xray of elbow. Following things are to be noted
- The extent of the fracture
- The degree of comminution
- The amount of disruption of the articular surface
- Displacement of the radial head
An anteroposterior view is useful to look for associated radial head or neck fracture can also be identified on this view
Classification of Olecranon Fractures
- Displaced less than 2 mm,
- Exhibit no change in position with gentle flexion to 90 degrees or with extension against gravity.
A. Avulsion fractures
B. Transverse/oblique fractures
C. Isolated comminuted fractures
- Type A – Extra-articular fractures
- Type B – Intra-articular fractures
- Type C – Intra-articular fractures of both the radial head and the olecranon
Type A – Simple transverse fracture
- Type B – Transverse impacted fracture
- Type C – Oblique fracture
- Type D – Comminuted fracture
- Type E – More distal fracture, which actually is extra-articular
- Type F – Fracture dislocation
Mayo Clinic Classification
- Type I – Nondisplaced
- Type II – Displaced but stable
- Type III – Associated instability of the elbow
Treatment of Olecranon Fractures
The treatment of olecranon fractures vary with individuals. In general, in young active patients the goal of treatment should be restoration of the articular surface, preservation of motor power, restoration of stability, and prevention of joint stiffness.
In older patients, the morbidity of the injury, treatment should be considered and treatment is guided by this and the levels of activity.
Conservative treatment should also be considered in patients with associated medical problems.
Surgery is indicated in
- Fractures with >2 mm of displacement
- Affected extensor mechanism
- Associated elbow instability
- Failure of non-operative treatment
The choice of surgical procedure varies with age and fracture pattern.
Open reduction and internal fixation is the treatment of choice displaced olecranon fractures. The choice of implant depends on the fracture pattern.
- Transverse fractures are very well treated by tension band wiring.
- Oblique fractures are treated preferably by intramedullary screw with or without tension band wiring over the screw.
- Plate fixation with a lag screw provides excellent stability for oblique fractures. Plate fixation is also recommended in severely comminuted fractures.
- Excision and triceps advancement may be indicated for severely comminuted fractures or for patients with osteoporotic bone.
After a stable fixation, the patient should be put on range of motion exercises for elbow after about 10 days.
Nondisplaced and Stable Olecranon Fracture
These fractures are treated by immobilization in a above elbow cast. Traditionally, the elbow was positioned in 30 degrees of flexion for fear of displacement of the fracture fragments. But long arm long arm cast with the elbow in 90 degrees of flexion for 3 to 4 weeks works well too and is more comfortable to the patients.
The cast is kept for 3-4 weeks and after that protected range of motion exercises are begun. Special care is taken not to move elbow beyond 90 degrees of flexion. This is continued for anothre 4 weeks.
In case of an elderly patient, the range of motion may be initiated earlier than 3 weeks depending upon the tolerance of the patient.
To avoid surprises, a follow-up x-ray should be obtained within 5 to 7 days after cast application to ascertain the position of the fragments.
Displaced Olecranon Fracture
These fractures must be treated by open reduction and internal fixation. Nonoperative treatment in these fractures may cause decrease in power of extension, loss of articular incongruity sand elbow stiffness.
The treatment of displaced olecranon aims at maintaining power of elbow extension, restore congruity of the articular surface, restore stability of the elbow and prevent stiffness of the joint.
In an avulsion fracture a transverse fracture line separates a small proximal fragment of the olecranon process from the rest of the ulna. This fracture is most common in elderly patients and is usually caused by an avulsion force
If the fragment is small, excision is the best treatment with repair of the triceps back to the bone. If the fragment is large then tension band wiring surgery should be done.
Transverse Fractures without Comminution
- Tension band wiring.
Transverse Fractures with Comminution
- Tension band technique
- ?late fixation with or without bone grafting
The fracture line runs obliquely, starting near the deepest part of the semilunar notch and running dorsally and distally to emerge on the subcutaneous crest of the proximal part of the ulna. It may be having an element of comminution.
A plate with lag screw fixation is preferable over the tension band in these fractures especially in fractures with comminution.
Isolated Comminuted Fractures
This includes all the severely comminuted fractures of the olecranon usually resulting from direct trauma . There are multiple fracture planes, and many fragments.
Associated fractures of the lower humerus, the radius/ulna, and the radial head may accompany.
These fractures are difficult to treat and pose quite a challenge. If there is no other associated injury, these fractures are best treated by excision of the olecranon and reattachment of the triceps tendon to the remaining bone, flush with the articular surface. Early ebow mobilisation should be started.
If excision is not possible, possible surgical stabilization by TBW or plating can be attempted.
- Severe injuries
- Restoration of alignment and stability is primary goal
Complications of Olecranon Fractures
- Hardware related symtoms
- Heterotopic ossification [ 13-14%]
- Non-unions [5%] of patients.
Most of the patients with olecranon fracture have near normal functions. One fourth of patients would develop asymptomatic raiographic evidence of arthrosis at 15- to 20-year follow-up.
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