Treatment of Non-Displaced Vertical Patellar Fractures
Non-displaced vertical patellar fractures with an intact extensor mechanism should be managed conservatively with immobilization and early functional rehabilitation, as these fractures have excellent healing potential without surgery. 1, 2, 3
Initial Assessment
Confirm the following criteria before proceeding with conservative management:
- Fracture displacement < 2 mm on radiographs
- Articular step-off < 2 mm
- Intact extensor mechanism (patient can actively extend the knee against gravity)
- Closed fracture (no skin breach)
If any of these criteria are not met, surgical intervention is indicated 1, 2.
Conservative Treatment Protocol
Immobilization Phase (Weeks 0-2)
- Apply a knee immobilizer or cylinder cast in full extension
- Allow full weight-bearing as tolerated with the brace locked in extension
- Patient may remove brace for hygiene but must maintain knee in extension
Early Mobilization Phase (Weeks 3-6)
- Begin passive range of motion exercises:
- Weeks 3-4: Progress to 30-60° flexion
- Weeks 5-6: Progress to 90° flexion
- Continue protected weight-bearing with brace
- Initiate quadriceps isometric exercises
Progressive Rehabilitation (Weeks 6-12)
- Advance to unlimited flexion and active mobilization
- Strengthen quadriceps and hamstrings progressively
- Wean from immobilizer as strength improves
- Return to sport-specific training at 3-6 months 4
Critical Monitoring
Obtain follow-up radiographs at 2 weeks to confirm the fracture remains non-displaced. Any increase in displacement or loss of extensor function mandates conversion to surgical fixation 1, 2.
Important Caveats
Vertical fractures are inherently less stable than transverse fractures due to the orientation of forces across the patella. While most non-displaced vertical fractures heal well conservatively, patient compliance with immobilization is critical. The high remodeling potential of bone, particularly in younger patients, allows for excellent outcomes even with minor residual deformity 5.
Do not confuse vertical fractures with displaced sagittal fractures - the latter often require surgical fixation with lag screws and cerclage wiring due to articular involvement and biomechanical instability 6.
The most common pitfall is inadequate initial immobilization leading to secondary displacement. Ensure patients understand they must maintain extension during the critical first 2-3 weeks, even when removing the brace for bathing.
Conservative management avoids the 14-33% complication rate associated with surgical hardware, including symptomatic hardware requiring removal, infection, and hardware failure 3, 7.