Concomitant posterior cruciate ligament injuries with direct injury-related patellar fractures

Posterior cruciate ligament (PCL) injuries and direct injury-related patellar fractures have similar causative factors. However, the mechanisms underlying these injuries differ. We aimed to evaluate the incidence and relationship between PCL injuries and direct injury-related patellar fractures.

Of the 195 patients diagnosed with a patellar fracture at our clinic during 2007-2011, 104 required surgical treatment and underwent the posterior drawer test under general anesthesia and magnetic resonance imaging. We assessed whether the causes of trauma, fracture classification, compression of the fracture fragment, and fracture displacement were related to the incidence of PCL injuries.

Of the 104 patients, 26 had concomitant PCL injuries with direct injury-related patellar fractures. Most of the PCL injuries were grades 1 and 2, observed in 14 and 9 patients, respectively. Among three patients with grade 3 PCL injury, only two required PCL reconstruction. No significant relationship was observed between the causes of trauma and the incidence of PCL injury. According to the fracture classification, lower pole and comminuted fractures were associated with higher incidence rates of PCL injury than transverse and vertical fractures. Compressed and displaced patellar fractures were also associated with higher incidence rates of PCL injury.

Although a PCL injury requiring surgical intervention was extremely rare, 25 % patients who required surgery for patellar fractures presented with a PCL injury. The incidence of a PCL injury was higher in the lower pole, comminuted, displaced, and compressed patellar fractures.