title: Prevalence of bilateral Discoid Lateral Menisci (DLM) in patients operated for symptomatic DLM with a follow-up study on their asymptomatic contralateral knees: a Magnetic Resonance Imaging (MRI) assessment.
abstract: BACKGROUND
  The purpose was to investigate prevalence of bilateral discoid lateral menisci (DLM) in Han Chinese patients who received surgery for symptomatic DLM, as well as a follow-up study of their asymptomatic contralateral knees using magnetic resonance imaging (MRI).
  
  
  METHODS
  A total of 110 patients [50 males and 60 females; average age: 21.95 ± 12.77 years (range: 6 to 67 years)] admitted to our hospital with symptomatic DLM were treated with arthroscopic surgery. The contralateral asymptomatic knees were evaluated for DLM by MRI. Postoperative clinical evaluation was performed using the Lysholm knee scoring scale and International Knee Documentation Committee subjective knee evaluation.
  
  
  RESULTS
  Eighty (72.73%) of 110 symptomatic DLM patients had bilateral DLM, of which 68 (85%) were of homotype (same type). Fourteen of 80 bilateral DLM patients were symptomatic and received operations in both knees. Twelve of remaining 66 bilateral DLM patients with asymptomatic one knee underwent a second arthroscopic surgery as their asymptomatic knees became symptomatic over the five-year interim. Of these 12 cases, seven exhibited no shift and five showed posterocentral meniscal shift. Furthermore, at least two cases showed progression from asymptomatic grade II to symptomatic grade III over the interim. All patients showed significant improvement after surgery.
  
  
  CONCLUSIONS
  The bilateral DLM rate of Han Chinese patients with symptomatic DLM was relatively high at 72.7 %, and 85 % of those were of homotype.
authors.affiliation: Department of Sports Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China. wenxinliu1@yeah.net.
authors.forename: Wen-Xin
authors.initials: WX
authors.lastname: Liu
authors.affiliation: Department of Sports Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China. zhaojinzhongdoctor@163.com.
authors.forename: Jin-Zhong
authors.initials: JZ
authors.lastname: Zhao
authors.affiliation: Department of Sports Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China. XiaoQiaoHuangfu@163.com.
authors.forename: Xiao-Qiao
authors.initials: XQ
authors.lastname: Huangfu
authors.affiliation: Department of Sports Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China. yaohuahe3@163.com.
authors.forename: Yao-Hua
authors.initials: YH
authors.lastname: He
authors.affiliation: Department of Sports Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China. XingGuangYang@yeah.net.
authors.forename: Xing-Guang
authors.initials: XG
authors.lastname: Yang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001182:Arthroscopy; D044466:Asian People; D058070:Asymptomatic Diseases; D002648:Child; D002681:China / Q000453:epidemiology; D000013:Congenital Abnormalities / Q000145:classification / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008592:Menisci, Tibial / Q000002:abnormalities* / Q000473:pathology / Q000601:surgery; D008875:Middle Aged; D015995:Prevalence; D055815:Young Adult