Olecranon fracture

Definition

• Olecranon fractures account for approximately 10% of upper extremity fractures¹
• There are 3 types of fractures
  • Type I
    • Nondisplaced
    • Accounts for 5-12% of olecranon fractures
  • Type II
    • Displaced at least 3mm, but collateral ligaments may still be intact
    • Most common 80-85% of olecranon fractures
  • Type III
    • Displaced and the ulnohumeral joint is unstable
    • This injury is a fracture-dislocation, collateral ligaments may be incompetent causing instability²
    • Accounts for 6% of olecranon fractures

Occurrence

• Common injury in adults, susceptible to direct blow³

Cause

• Acute and traumatic event such as fall on elbow
• Avulsion fractures may also occur from eccentric contraction of the triceps tendon

Risk factors

• 50 years of age or older (mean age is 57)
• Males more likely to sustain an injury at a younger age

Development

• Posttraumatic arthritis occurs in approximately 20% of cases and persistent malreduction >2mm of the articular surface is associated with this outcome⁴
• In fractures with significant comminution, inadvertent malreduction by narrowing the greater sigmoid notch may further predispose the patient to arthritis⁵
• A displaced fracture may interfere with the extensor mechanism resulting in loss of active elbow extension
  • The pull of the triceps is the key deforming cause
• The ulnar nerve is at risk of involvement due to its position

Examination

• If displaced there may be a palpable gap
• Passive flexion and extension may be limited (capsular pattern)
• Resisted extension is painful and weak
• Tenderness

Prognosis

• In general
  • Patients usually have a good functional outcome after treatment⁶
    • Approximately 10-15 degree loss of extension may occur, although this is usually not clinically significant
    • Long-term follow-up ranging 15-25 years reported good or excellent functional outcome in 96% of patients⁷
    • Fractures have a high rate of healing with a nonunion rate of approximately 1%⁸

Treatment

• Type I
  • Immobilization – posterior splint in slight extension 45-90 degrees of flexion
    • Followed by progressive active range of motion exercises with avoidance of active extension https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3492613/
  • Type II and III
    • Generally require surgery
    • Type II may be treated non-operative. They may lose full elbow extension due to disruption of the extensor mechanism but in some patients this is thought to be preferential to the risk of surgery