What is the treatment for a non-displaced patella fracture?

Treatment for Non-Displaced Patella Fracture

Non-displaced patella fractures with an intact extensor mechanism should be treated conservatively with immobilization, as this approach provides good functional outcomes while avoiding surgical complications.

Diagnosis and Assessment

• Diagnosis is based on:

  • Injury mechanism (direct blow or excessive tension through extensor mechanism)
  • Physical examination (inability to actively extend knee, tenderness, effusion)
  • Radiological findings (standard anteroposterior and lateral views)

• Key assessment points:

  • Displacement (<2-3mm step-off and <1-4mm displacement indicates non-displaced)
  • Integrity of extensor mechanism (ability to actively extend knee)
  • Comminution pattern
  • Associated soft tissue damage

Conservative Management Protocol

For non-displaced patella fractures with intact extensor mechanism:

1. Immobilization:

   • Knee immobilization in extension using a cast or brace 1
   • Duration typically 4-6 weeks depending on healing progress

2. Early Rehabilitation:

   • Early finger and hand motion to prevent edema and stiffness 2
   • Progressive rehabilitation once immobilization is discontinued
   • A directed home exercise program can be as effective as supervised therapy 2

3. Follow-up Monitoring:

   • Regular radiographic assessment to ensure maintained reduction
   • Clinical evaluation of extensor mechanism function
   • Monitoring for complications

Surgical Indications

Surgery is indicated when:

• Displacement >2-3mm step-off or >1-4mm gap 1, 3
• Disruption of the extensor mechanism 1
• Articular incongruity
• Open fractures

Potential Complications

• Joint stiffness
• Extension weakness
• Patellofemoral arthritis 1
• Chronic pain
• Post-traumatic arthritis if articular surface not properly restored 3

Special Considerations

• For elderly patients with fragility fractures:

  • Evaluate for osteoporosis risk factors 2
  • Consider calcium and vitamin D supplementation 2
  • Implement secondary fracture prevention strategies
  • Avoid prolonged bed rest which can cause significant muscle strength loss (15% of lower limb strength after just 10 days) 2

• For comminuted fractures:

  • CT imaging may be necessary for better understanding of fracture complexity 3
  • More likely to require surgical intervention for anatomic restoration

Prognosis

With appropriate conservative management of non-displaced fractures:

• Good functional outcomes can be expected
• Early rehabilitation helps prevent knee stiffness and contractures 4
• Return to previous activity level is possible in most cases

Common Pitfalls to Avoid

1. Failing to recognize extensor mechanism disruption
2. Inadequate immobilization leading to displacement
3. Overly aggressive early mobilization in unstable fractures
4. Delayed rehabilitation leading to stiffness and weakness
5. Missing associated injuries (ligamentous or meniscal)

The evidence strongly supports conservative management for non-displaced patella fractures with an intact extensor mechanism, as this approach avoids the complications associated with surgery while achieving good functional outcomes 1, 3.