title: Evaluation of posterior lateral femoral condylar hypoplasia using axial MRI images in patients with complete discoid meniscus.
abstract: OBJECTIVE
  Hypoplasia of the lateral femoral condyle has been reported in discoid lateral meniscus patients, but associated imaging findings in the axial plane have not been characterized. In this study, we aimed to identify differences in the lateral femoral condyle between patients with discoid lateral meniscus and those with normal menisci using axial MRI images.
  
  
  METHODS
  Twenty-three patients (24 knees) with complete discoid lateral meniscus, 43 (45 knees) with incomplete discoid lateral meniscus, and 50 with normal menisci (50 knees) were enrolled and distributed into three groups. Two new angles, posterior lateral condylar angle (PLCA) and posterior medial condylar angle (PMCA), were measured on axial MRI images; the posterior condylar angle (PCA) was also measured. Differences between the three groups in the PLCA, PMCA, PCA, and PLCA/PMCA were analysed. The predictive value of PLCA and PLCA/PMCA for complete discoid lateral meniscus was assessed.
  
  
  RESULTS
  In the complete discoid lateral meniscus group, PLCA and PLCA/PMCA were significantly smaller compared with the normal meniscus group and the incomplete discoid lateral meniscus group (P < 0.001). A significantly larger PCA was identified in the complete discoid lateral meniscus group compared with the incomplete discoid lateral meniscus group (P < 0.05) and normal meniscus group (P < 0.05). Both PLCA and PLCA/PMCA showed excellent predictive value for complete discoid lateral meniscus.
  
  
  CONCLUSIONS
  Hypoplasia of the posterior lateral femoral condyle is typically seen in patients with complete discoid lateral meniscus. PLCA and PLCA/PMCA can be measured from axial MRI images and used as excellent predictive parameters for complete discoid lateral meniscus.
  
  
  METHODS
  Diagnostic study, Level III.
authors.affiliation: Department of Orthopaedics, The Affiliated Drum Tower Hospital of Nanjing University Medical School, 321 Zhongshan Road, Nanjing, 210008, Jiangsu, People's Republic of China.
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Xu
authors.affiliation: Department of Orthopaedics, The Affiliated Drum Tower Hospital of Nanjing University Medical School, 321 Zhongshan Road, Nanjing, 210008, Jiangsu, People's Republic of China.
authors.forename: Dongyang
authors.initials: D
authors.lastname: Chen
authors.affiliation: Department of Orthopaedics, The Affiliated Drum Tower Hospital of Nanjing University Medical School, 321 Zhongshan Road, Nanjing, 210008, Jiangsu, People's Republic of China.
authors.forename: Dongquan
authors.initials: D
authors.lastname: Shi
authors.affiliation: Department of Orthopaedics, The Affiliated Drum Tower Hospital of Nanjing University Medical School, 321 Zhongshan Road, Nanjing, 210008, Jiangsu, People's Republic of China.
authors.forename: Jin
authors.initials: J
authors.lastname: Dai
authors.affiliation: Department of Orthopaedics, The Affiliated Drum Tower Hospital of Nanjing University Medical School, 321 Zhongshan Road, Nanjing, 210008, Jiangsu, People's Republic of China.
authors.forename: Yao
authors.initials: Y
authors.lastname: Yao
authors.affiliation: Department of Orthopaedics, The Affiliated Drum Tower Hospital of Nanjing University Medical School, 321 Zhongshan Road, Nanjing, 210008, Jiangsu, People's Republic of China. jiangqing112@hotmail.com.
authors.forename: Qing
authors.initials: Q
authors.lastname: Jiang
mesh_terms: D000328:Adult; D001848:Bone Diseases, Developmental / Q000175:diagnosis*; D002357:Cartilage Diseases / Q000175:diagnosis* / Q000473:pathology; D004838:Epiphyses; D005260:Female; D005269:Femur / Q000002:abnormalities / Q000473:pathology*; D006801:Humans; D007719:Knee Joint / Q000002:abnormalities / Q000473:pathology*; D038061:Lower Extremity Deformities, Congenital / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging; D008297:Male; D008592:Menisci, Tibial / Q000002:abnormalities / Q000473:pathology*; D008875:Middle Aged; D012189:Retrospective Studies; D055815:Young Adult
keywords: Discoid meniscus; Hypoplasia; MRI; Posterior lateral femoral condylar