Olecranon fracture or olecranon process is a fracture of the large curved eminence called the olecranon process that formes the point of the elbow. It is the point where we rest our elbow on the table in a sitting position.
Olecranon is a part of the ulna bone and is the uppermost posterior aspect of the ulna. Olecranon fractures range from simple nondisplaced fractures to complex fracture-dislocations of the elbow joint. Olecranon fracture is a common fracture due to the subcutaneous position of olecranon on the point of the elbow.
The olecranon process lies beneath the skin and it is very vulnerable to direct trauma.
The injury is less common in children.
Together with the coronoid process, the olecranon forms the articular surface for articulation with the trochlea. This articulation allows movement only in the 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 uppermost posterior part of the ulna that contributes to the articular surface of ulna [trochlear groove or notch], anterior contribution being by the coronoid process.
The medial part of the lower end of the end of the humerus and forms greater posterior part of trochlear notch. Trochlear notch is a concavely shaped structure which participates in trochleohumeral joint and is responsible for flexion-extension movements of the elbow.
In the lateral part, the radius articulates with the humerus.
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 prevents anterior translation of the ulna with respect to the distal humerus. The anterior surface of the olecranon is covered with articular cartilage. Therefore, most of the fractures except the rare tip fractures are intra-articular fractures.
The triceps muscle inserts into the posterior third of the olecranon and proximal ulna. The periosteum of the olecranon blends with the triceps. Therefore, in olecranon fractures extension mechanism is affected.
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.
Hyperextension injuries of the 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, the elbow is swollen and there is tenderness over the olecranon area. The mobility of the fragment may be noted. The 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].
Imaging
Olecranon fracture is best visualized in lateral view x-ray of the elbow. Following things are to be noted
- Fracture location and if reaches the articular surface
- Displacement and the gap
- Presence of comminution and degree of comminution
On the lateral view, the olecranon fractures appear as a lucency usually reaching the trochlear groove articular surface.
Following associated findings should be looked for presence or absence
- Fracture of the coronoid process
- Fracture or dislocation of the radial head
- Presence of fracture of the distal humerus
Classification of Olecranon Fractures
Colton’s classification
Nondisplaced/Stable
- Displaced less than 2 mm,
- Exhibit no change in position with gentle flexion to 90 degrees or with extension against gravity.
Displaced fractures
A. Avulsion fractures
B. Transverse/oblique fractures
C. Isolated comminuted fractures
D. Fracture/dislocations
AO Classification
- Type A – Extra-articular fractures
- Type B – Intra-articular fractures
- Type C – Intra-articular fractures of both the radial head and the olecranon
Schatzker Classification
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 Approach for Olecranon Fractures
The treatment of olecranon fractures varies with individuals.
In young persons, the goal is
- To restore articular surface and stability
- Preserving the motor power
- Prevention of joint stiffness.
In older patients, apart from the severity of the injury, the treatment is guided by the levels of activity.
In the patients who have concomitant medical conditions, conservative treatment should be considered.
Indications for surgery in olecranon fracture are
- >2 mm of displacement
- Affected extensor mechanism
- Associated elbow instability
- Failure of non-operative treatment
Type of Surgery
Fracture pattern and age of the patient guide the choice of surgical procedure.
Open reduction and internal fixation is the treatment of choice displaced olecranon fractures. The choice of implant depends on the fracture pattern.
- Transverse fractures
- Oblique fractures
- intramedullary screw with or without tension band wiring over the screw.
- Plate fixation with a lag screw
- Severely comminuted fractures
- Plate fixation
- Excision and triceps advancement
- Severe Osteoporosis
- Excision and triceps advancement
After a stable fixation, the patient should be put on the range of motion exercises for the elbow after about 10 days.
Treatment Options Depending on Fracture Type
Nondisplaced and Stable Olecranon Fracture
These fractures are treated by immobilization in an 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 position of the fragments is checked after 5-7 days by x-ray of the elbow.
The cast is kept for 3-4 weeks and after that protected range of motion, exercises are begun and continued for another 4 weeks.
In the case of an elderly patient, the range of motion may be initiated earlier.
Displaced Olecranon Fracture
Open reduction and internal fixation is the treatment of choice. Nonoperative treatment is discouraged as it would lead to a non-anatomical union, loss of extension power, articular incongruity [leading to degenerative changes] and elbow stiffness.
The treatment of displaced olecranon aims at maintaining the power of elbow extension, restore congruity of the articular surface, restore stability of the elbow and prevent stiffness of the joint.
Avulsion Fractures
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
Transverse Fractures without Comminution
Transverse Fractures with Comminution
- Tension band technique
- Plate fixation with or without bone grafting
Oblique Fractures
A plate with lag screw fixation is preferable over the tension band in these fractures especially in fractures with comminution.
Comminuted Fractures
There are multiple fracture planes and many fragments.
Associated fractures of the lower humerus, the radius/ulna, and the radial head may accompany.
If there is no other associated injury, excision of the olecranon and reattachment of the triceps tendon to the remaining bone should be done, flush with the articular surface. Early elbow mobilization should be started.
If excision is not possible, possible surgical stabilization by TBW or plating can be attempted.
Fracture-Dislocation
Presence of other injuries would guide the treatment choice for olecranon.
Complications of Olecranon Fractures
- Hardware related symptoms
- Heterotopic ossification
- Non-union
- Infection
Prognosis
With proper treatment, most of the patients with olecranon fracture have near normal functions.
About 25% of the patients have been reported to develop asymptomatic radiographic evidence of arthrosis after 15- to 20-year follow-up.
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