title: Concomitant posterior cruciate ligament injuries with direct injury-related patellar fractures.
abstract: BACKGROUND
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Orthopedic Trauma Division, Trauma Center, Gacheon University Gil Hospital, 21, Namdong-daero 774 beon-gil, Namdong-gu, Incheon, 405-760, Korea.
authors.forename: Yong-Cheol
authors.initials: YC
authors.lastname: Yoon
authors.affiliation: Department of Orthopaedic Surgery, Gacheon University Gil Hospital, 21, Namdong-daero 774 beon-gil, Namdong-gu, Incheon, 405-760, Korea.
authors.forename: Sung-Soo
authors.initials: SS
authors.lastname: Jeon
authors.affiliation: Department of Orthopaedic Surgery, Gacheon University Gil Hospital, 21, Namdong-daero 774 beon-gil, Namdong-gu, Incheon, 405-760, Korea. sim_ja@daum.net.
authors.forename: Jae-Ang
authors.initials: JA
authors.lastname: Sim
authors.affiliation: Department of Orthopaedic Surgery, Gacheon University Gil Hospital, 21, Namdong-daero 774 beon-gil, Namdong-gu, Incheon, 405-760, Korea.
authors.forename: Byung-Kag
authors.initials: BK
authors.lastname: Kim
authors.affiliation: Department of Orthopaedic Surgery, Gacheon University Gil Hospital, 21, Namdong-daero 774 beon-gil, Namdong-gu, Incheon, 405-760, Korea.
authors.forename: Beom-Koo
authors.initials: BK
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D000070598:Anterior Cruciate Ligament Injuries / Q000150:complications / Q000601:surgery*; D001182:Arthroscopy; D005260:Female; D050723:Fractures, Bone / Q000150:complications / Q000601:surgery*; D006801:Humans; D015994:Incidence; D007718:Knee Injuries / Q000150:complications / Q000601:surgery*; D007719:Knee Joint / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010329:Patella / Q000293:injuries*; D016119:Posterior Cruciate Ligament / Q000293:injuries* / Q000601:surgery; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D055815:Young Adult
keywords: Direct injury; Fracture; Patella; Posterior cruciate ligament