title: Radiographic evaluation of complete and incomplete discoid lateral meniscus.
abstract: OBJECTIVE
  The aim of this retrospective study was (1) to evaluate the radiographic features to differentiate arthroscopically confirmed complete and incomplete discoid lateral meniscus (DLM) (2) to determine the cutoff values for any parameter that was found to differentiate complete from incomplete DLM.
  
  
  METHODS
  We retrospectively analyzed plain knee radiographs of 130 arthroscopically proven DLM. Seventy-nine patients had complete DLM and 51 patients incomplete DLM. Knee radiographs from 52 patients with arthroscopically proven normal lateral meniscus acted as control group. Radiographic parameters measured included fibular height, lateral joint space, condylar cutoff sign, height of lateral tibial spine, obliquity of lateral tibial spine, squaring of the lateral femoral condyle, and cupping of the lateral tibial plateau.
  
  
  RESULTS
  Among radiographic parameters, high fibular head, widening of the lateral joint space and femoral condylar cutoff sign showed statistically significant (p<0.0001) differences between complete and incomplete DLM. At specific threshold points of fibular height<11 mm, lateral joint space>6 mm and condylar cutoff sign<0.80, the diagnosis of complete DLM revealed 87.3% sensitivity, 81.6% specificity and 78.4% positive predictive value (PPV) for the fibular height, 81.0% sensitivity, 86.6% specificity and 83.1% PPV for the lateral joint space, and 86.1% sensitivity, 83.5% specificity and 80% PPV for the condylar cutoff sign.
  
  
  CONCLUSIONS
  Radiographic features of fibular height, lateral joint space and condylar cut off sign can be used for screening of a complete type of DLM. However, radiographs are not a reliable screening tool for an incomplete DLM.
  
  
  METHODS
  IV, Case Series.
authors.affiliation: Department of Orthopaedic Surgery, Inje University, Ilsan Paik Hospital, Ilsan, Republic of Korea.
authors.forename: Jae Gwang
authors.initials: JG
authors.lastname: Song
authors.affiliation: Department of Orthopaedic Surgery, Inje University, Ilsan Paik Hospital, Ilsan, Republic of Korea.
authors.forename: Jae Hwi
authors.initials: JH
authors.lastname: Han
authors.affiliation: Department of Orthopaedic Surgery, Barunsesang Hospital, Bundang, Republic of Korea.
authors.forename: Jae Ho
authors.initials: JH
authors.lastname: Kwon
authors.affiliation: Asian Orthopaedic Institute, Asian Heart Institute and Research Centre, Mumbai, India.
authors.forename: Gautam M
authors.initials: GM
authors.lastname: Shetty
authors.affiliation: Department of Surgery, Orthopaedic Section, Saint Louis University Hospital of the Sacred Heart, Baguio, Philippines.
authors.forename: Leo Anthony M
authors.initials: LA
authors.lastname: Franco
authors.affiliation: Department of Radiology, Won-dang Radiology Hospital, Goyang, Republic of Korea.
authors.forename: Dae Young
authors.initials: DY
authors.lastname: Kwon
authors.affiliation: Department of Orthopaedic Surgery, Inje University, Ilsan Paik Hospital, Ilsan, Republic of Korea. Electronic address: kwnhamj@hotmail.com.
authors.forename: Kyung Wook
authors.initials: KW
authors.lastname: Nha
mesh_terms: D000293:Adolescent; D000328:Adult; D001182:Arthroscopy / Q000379:methods*; D005260:Female; D006801:Humans; D007592:Joint Diseases / Q000000981:diagnostic imaging* / Q000601:surgery; D007719:Knee Joint / Q000000981:diagnostic imaging* / Q000601:surgery; D008297:Male; D008592:Menisci, Tibial / Q000000981:diagnostic imaging* / Q000601:surgery; D008875:Middle Aged; D011859:Radiography; D012189:Retrospective Studies; D055815:Young Adult
keywords: Arthroscopy; Discoid lateral meniscus; Knee; Plain radiograph