Treatment of Patellar Fractures
The treatment of patellar fractures depends primarily on fracture displacement and integrity of the extensor mechanism, with surgical treatment recommended for fractures that disrupt the extensor mechanism or have more than 2-3 mm of step-off and more than 1-4 mm of displacement. 1
Diagnostic Evaluation
Initial imaging: Radiographs are the first-line examination for assessment of patellar fractures and should include:
- Anteroposterior and lateral views
- Axial (skyline) view to assess patellar tilt or subluxation
- Images should include the entire knee joint 2
Advanced imaging: Consider when radiographs are inconclusive
- CT: Highly sensitive for detecting fracture patterns and comminution
- MRI: Useful for assessing soft tissue involvement and extensor mechanism integrity
- Both modalities are more effective when metal artifact reduction techniques are used 2
Classification of Patellar Fractures
Patellar fractures can be classified as:
- Transverse fractures: Often associated with patellar maltracking
- Vertical fractures: Frequently occur through fixation holes
- Comminuted fractures: Multiple fragments
- Polar fractures: Affecting superior or inferior poles 1
Treatment Algorithm
1. Non-Operative Treatment
Indicated for:
- Undisplaced fractures (less than 2-3 mm step-off and less than 1-4 mm displacement)
- Intact extensor mechanism
Management includes:
- Immobilization with cast or brace
- Early range of motion exercises as tolerated
- Progressive weight-bearing 1
2. Operative Treatment
Indicated for:
- Disrupted extensor mechanism
- Displacement >2-3 mm step-off or >1-4 mm gap
- Articular incongruity
Surgical options include:
A. Tension Band Wiring
- Most commonly employed technique for transverse fractures
- Uses K-wires or cannulated screws with tension band wire
- Caution: Hardware removal often necessary (30.6% in one study) due to implant-related pain 3
B. Suture Fixation
- Particularly useful for inferior pole fractures
- Non-absorbable braided suture woven through patellar tendon and placed through drill holes
- Lower hardware-related complications compared to tension band wiring (7.6% vs 30.6% reoperation rate) 3
C. Partial or Total Patellectomy
- Reserved for severely comminuted fractures not amenable to reconstruction
- Long-term outcomes comparable to other surgical interventions requiring intervention 4
D. Percutaneous Fixation
- Less invasive alternative to open surgery
- May be considered for simple fracture patterns 5
Postoperative Management
- Early mobilization with protected range of motion exercises
- Progressive weight-bearing as tolerated
- Physical therapy focusing on quadriceps strengthening
- Hardware removal may be necessary after fracture healing if symptomatic 1
Potential Complications
- Nonunion
- Infection
- Posttraumatic arthritis
- Arthrofibrosis
- Symptomatic hardware
- Extensor mechanism insufficiency 6
Prognosis and Follow-up
- Regular follow-up at 2-4 week intervals initially
- Radiographic healing typically occurs within 8-12 weeks
- Full functional recovery may take 3-6 months
- Patients requiring reoperation or hardware removal may experience diminished range of motion 3
Special Considerations
- Comminuted fractures present significant challenges and may require advanced reconstruction techniques
- CT imaging may be beneficial pre-operatively to better understand fracture complexity and modify treatment accordingly 1
- Anatomical reconstruction of the articular surface is crucial to prevent posttraumatic osteoarthritis 1
The treatment choice should be based on fracture pattern, displacement, extensor mechanism integrity, and patient factors to optimize functional outcomes and minimize complications.