What is the treatment for a patellar fracture?

Treatment of Patellar Fracture

The treatment of patellar fractures depends on fracture displacement and integrity of the extensor mechanism, with non-displaced fractures with intact extensor mechanism treated conservatively, while displaced fractures (>2-3mm step-off or >1-4mm displacement) or those with disrupted extensor mechanism require surgical fixation, typically with modified anterior tension band wiring. 1

Diagnostic Evaluation

• Initial assessment should include evaluation of the extensor mechanism integrity and radiographic imaging 2
• Standard radiographs (anteroposterior and lateral views) are usually sufficient for assessment of patellar fractures and can guide treatment decisions 3
• CT with metal artifact reduction techniques may be beneficial for detecting complex fracture patterns or complications, especially in patients with prostheses 3, 1
• Weight-bearing axial radiographs are recommended to better assess patellofemoral kinematics when evaluating alignment issues 3

Treatment Algorithm Based on Fracture Type

Non-Displaced Fractures

• Conservative treatment is appropriate for non-displaced fractures with an intact extensor mechanism 4, 1
• Treatment typically involves immobilization in a cast or brace with the knee in extension 5
• Early rehabilitation is recommended to avoid knee joint contractures and cartilage degeneration 5

Displaced Fractures

• Surgical intervention is indicated for:
  • Fractures with >2-3mm articular step-off 4, 1
  • Fractures with >1-4mm displacement 4, 1
  • Any disruption of the extensor mechanism 2, 4

Surgical Techniques by Fracture Pattern

Transverse (2-part) Fractures

• Modified anterior tension band wiring is the treatment of choice 5
• For optimal stability, tension band wiring can be combined with cannulated screw fixation due to its biomechanical superiority 5, 6
• Two parallel cannulated lag screws with tension band wiring provide superior stability for horizontally displaced two-part fractures 6

Comminuted Fractures

• Open reduction and fixation with small fragment screws or angular stable plates for anatomic restoration of the retropatellar surface 5
• Additional circular cerclage wiring (using metal wires or resorbable/non-resorbable materials) increases fixation stability 5
• In severely comminuted fractures where reconstruction is not possible, partial patellectomy may be considered 6

Distal Avulsion Fractures

• Fixation with small fragment screws protected by a transtibial McLaughlin cerclage 5

Postoperative Care and Rehabilitation

• Early rehabilitation is crucial regardless of treatment method to:
  • Prevent knee joint contractures 5, 6
  • Avoid cartilage degeneration 5
  • Restore functional capacity 1
• Rehabilitation protocols should focus on gradual restoration of range of motion and strengthening of the quadriceps mechanism 2

Complications and Considerations

• Symptomatic hardware is the most common complication following operative treatment, often requiring removal after fracture healing 4, 1
• Patellofemoral osteoarthritis is common after patellar fractures, especially if anatomic reduction of the articular surface is not achieved 2, 1
• Functional impairment may persist even after successful fracture healing 4
• Total patellectomy should be considered only as a rare salvage procedure due to its severe functional impairment 5, 6

Special Considerations for Elderly Patients

• Patellar fractures in elderly patients require careful consideration of bone quality, activity level, and compliance 5
• Functional outcomes are particularly important in elderly patients as impairment may lead to increased fall risk 1
• Appropriate pain management and early mobilization are essential components of postoperative care 3