From the Guidelines
Surgical intervention is necessary for comminuted patellar fractures with significant displacement or disruption of the extensor mechanism, while non-displaced fractures may be managed conservatively with immobilization and physical therapy. A comminuted patellar fracture is a complex break of the kneecap into three or more fragments, requiring careful evaluation of fracture displacement and extensor mechanism integrity to guide treatment. For non-displaced fractures with an intact extensor mechanism, conservative management with a knee immobilizer or hinged brace for 4-6 weeks is recommended, along with weight-bearing as tolerated and progressive range of motion exercises, as supported by the principles outlined in 1.
Key considerations in managing comminuted patellar fractures include:
- Fracture displacement: Displacement greater than 2-3mm or step-off may necessitate surgical intervention.
- Extensor mechanism integrity: Disruption of the extensor mechanism requires surgical repair to restore knee function.
- Pain management: Typically involves acetaminophen and NSAIDs for 1-2 weeks.
- Rehabilitation: Physical therapy is crucial for restoring quadriceps strength and knee function, whether after surgical or non-surgical management.
In cases where surgery is indicated, techniques such as open reduction internal fixation with tension band wiring, partial patellectomy, or rarely total patellectomy may be employed. Post-surgery rehabilitation includes protected weight-bearing for 4-6 weeks, followed by progressive strengthening exercises. The goal of treatment is to minimize morbidity, reduce the risk of complications such as post-traumatic arthritis, and optimize quality of life by restoring normal knee function, as would be prioritized in real-life clinical practice, considering the principles mentioned in 1.
From the Research
Treatment Options for Comminuted Patellar Fractures
- Surgical treatment is recommended for fractures that disrupt the extensor mechanism or have more than 2 to 3 mm of step-off and more than 1 to 4 mm of displacement 2
- Tension band fixation is the most commonly employed surgical technique, but hardware has to be removed after fracture healing due to implant-related pain 2
- Anterior mesh plating with biplanar placement of locking screws provides superior stability for fixation of comminuted patellar fractures compared to antero-lateral mesh plating and tension band wiring 3
- Headless compression screws with additional separate vertical wiring can be used to fix loose articular fragments and provide good clinical outcomes 4
- Patellectomy with advancement of vastus medialis obliquus surgery may result in more participants with a 'good' result and fewer participants experiencing knee pain compared to simple patellectomy 5
Fixation Techniques
- Non-absorbable suture cerclage and Nitinol patellar concentrator can be used to fix comminuted patellar fractures, resulting in satisfactory outcomes without obvious complications 6
- Biplanar fixed angle plate constructs can be used to convert pulling forces on the anterior aspect of the patella into compression forces across the fracture site 3
- Percutaneous osteosynthesis using novel devices or methods can improve knee pain and reduce adverse events compared to open surgery 5
Clinical Outcomes
- The average range of motion arc after treatment of comminuted patellar fractures can be around 134.2°, and the mean Lysholm and Bostman scores can be around 94.4 and 28.7, respectively 4
- Thigh muscle wasting can be observed in some patients, but no patient had more than 1.5 cm difference in thigh circumference girth between the injured and uninjured lower limbs 4
- The average VAS-related pain score after treatment of comminuted patellar fractures can be around 0.4 4