title: Traumatic posterior root tear of the medial meniscus in patients with severe medial instability of the knee.
abstract: OBJECTIVE
  To examine the incidence and diagnostic rate of traumatic medial meniscus posterior root tear associated with severe medial instability and to evaluate the effectiveness of pullout repair.
  
  
  METHODS
  From 2007 to 2011, 51 patients who underwent operation due to multiple ligament injuries including medial collateral ligament rupture were reviewed retrospectively. The International Knee Documentation Committee (IKDC) subjective and Lysholm score were evaluated pre- and postoperatively. Postoperative magnetic resonance imaging (MRI) was performed, and if indicated, a second-look arthroscopic examination was conducted.
  
  
  RESULTS
  Fourteen out of 51 patients were associated with severe medial instability. Seven patients were diagnosed with traumatic medial meniscus posterior root tear and underwent arthroscopic pullout repair. Five of them were missed at initial diagnosis using MRI. In seven patients, the mean Lysholm and IKDC subjective scores improved from 74.6 ± 10.3 and 47.6 ± 7.3 to 93.0 ± 3.7 and 91.6 ± 2.6, respectively. All showed complete healing of meniscus root on follow-up MRI and second-look arthroscopy.
  
  
  CONCLUSIONS
  Medial meniscus posterior root tear may occur in severe medial instability from trauma. It is a common mistake that surgeons may not notice on the diagnosis of those injuries using MRI. Therefore, a high index of suspicion is required for the diagnosis of medial meniscus posterior root tear in this type of injuries. The traumatic medial meniscus posterior root tear could be healed successfully using arthroscopic pullout repair technique.
  
  
  CONCLUSIONS
  The possibility of the medial meniscus posterior root tear should be considered in severe medial instability and arthroscopic pullout repair can be an effective option for treatment.
  
  
  METHODS
  Case series with no comparison group, Level IV.
authors.affiliation: Department of Orthopedic Surgery, Gangneung Asan Hospital, College of Medicine, Ulsan University, Gangneung, Korea.
authors.forename: Ho Jong
authors.initials: HJ
authors.lastname: Ra
authors.affiliation: Department of Orthopedic Surgery, Seoul Paik Hospital, College of Medicine, Inje University, 85, Jeo-dong 2Ga, Jung-gu, Seoul, Korea.
authors.forename: Jeong Ku
authors.initials: JK
authors.lastname: Ha
authors.affiliation: Department of Orthopedic Surgery, Seoul Paik Hospital, College of Medicine, Inje University, 85, Jeo-dong 2Ga, Jung-gu, Seoul, Korea.
authors.forename: Ho Su
authors.initials: HS
authors.lastname: Jang
authors.affiliation: Department of Orthopedic Surgery, Seoul Paik Hospital, College of Medicine, Inje University, 85, Jeo-dong 2Ga, Jung-gu, Seoul, Korea. boram107@hanmail.net.
authors.forename: Jin Goo
authors.initials: JG
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D000328:Adult; D001182:Arthroscopy / Q000379:methods*; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000175:diagnosis / Q000209:etiology / Q000601:surgery*; D007718:Knee Injuries / Q000150:complications / Q000175:diagnosis / Q000601:surgery*; D007719:Knee Joint / Q000473:pathology / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D008592:Menisci, Tibial / Q000601:surgery; D012189:Retrospective Studies; D012421:Rupture; D012720:Severity of Illness Index; D000070600:Tibial Meniscus Injuries; D016896:Treatment Outcome; D055815:Young Adult
keywords: Low diagnostic rate; Medial meniscus; Pullout root repair; Severe knee medial instability; Traumatic medial meniscus posterior root tear