title: Clinical features and injury patterns of medial collateral ligament tibial side avulsions: "wave sign" on magnetic resonance imaging is essential for diagnosis.
abstract: BACKGROUND
  Medial collateral ligament tibial avulsion is rare. Consequently, diagnostic criteria and a treatment regimen for medial collateral ligament tibial side avulsions remain to be established. The purpose of this study is to clarify the clinical features of medial collateral ligament tibial side avulsions.
  
  
  METHODS
  We performed a retrospective clinical and magnetic resonance imaging review of a consecutive series of 12 medial collateral ligament tibial side avulsions. All patients were treated operatively and the final diagnosis was made based on the intraoperative findings. Post-injury magnetic resonance imaging studies were reviewed to assess injury patterns with respect to the intraoperative findings.
  
  
  RESULTS
  Eleven of 12 cases (92%) had grade III valgus laxity (unstable to valgus stress at both 0° and 30° of flexion) on an examination under anesthesia. Concomitant anterior cruciate ligament tear was noticed in all cases. Intraoperative findings were classified into 3 types depending on the location of the ruptured end of the superficial medial collateral ligament with respect to the pes anserinus tendons. Magnetic resonance imaging depicted characteristic waving ("wave sign") of the superficial layer of medial collateral ligament in all cases.
  
  
  CONCLUSIONS
  "Wave sign" of the superficial layer of medial collateral ligament on magnetic resonance imaging is essential for diagnosing medial collateral ligament tibial side avulsions. Based on the clinical features and injury patterns, operative treatment is primarily recommended for medial collateral ligament tibial side avulsions.
  
  
  METHODS
  Case series, Level IV.
authors.affiliation: Department of Orthopaedic Surgery, Faculty of Medicine, The University of Tokyo, Tokyo, Japan. Electronic address: takeos-tky@umin.ac.jp.
authors.forename: Shuji
authors.initials: S
authors.lastname: Taketomi
authors.affiliation: Department of Orthopaedic Sports Surgery, Kantoh Rosai Hospital, Kanagawa, Japan.
authors.forename: Eiji
authors.initials: E
authors.lastname: Uchiyama
authors.affiliation: Department of Orthopaedic Surgery, Teikyo University School of Medicine, Tokyo, Japan.
authors.forename: Takumi
authors.initials: T
authors.lastname: Nakagawa
authors.affiliation: Department of Orthopaedic Surgery, Faculty of Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Takeda
authors.affiliation: Department of Orthopaedic Sports Surgery, Kantoh Rosai Hospital, Kanagawa, Japan.
authors.forename: Shuichi
authors.initials: S
authors.lastname: Nakayama
authors.affiliation: Department of Orthopaedic Sports Surgery, Kantoh Rosai Hospital, Kanagawa, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Fukai
authors.affiliation: Department of Orthopaedic Sports Surgery, Kantoh Rosai Hospital, Kanagawa, Japan.
authors.forename: Takaki
authors.initials: T
authors.lastname: Sanada
authors.affiliation: Department of Orthopaedic Sports Surgery, Kantoh Rosai Hospital, Kanagawa, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Iwaso
mesh_terms: D000293:Adolescent; D000328:Adult; D001265:Athletic Injuries / Q000150:complications / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000209:etiology / Q000473:pathology* / Q000601:surgery; D007718:Knee Injuries / Q000150:complications / Q000473:pathology* / Q000601:surgery; D008279:Magnetic Resonance Imaging; D008297:Male; D017888:Medial Collateral Ligament, Knee / Q000293:injuries* / Q000601:surgery; D020127:Recovery of Function; D015203:Reproducibility of Results; D012189:Retrospective Studies; D016896:Treatment Outcome; D055815:Young Adult
keywords: Detachment; Magnetic resonance imaging; Medial collateral ligament injury; Tibial side avulsion; Wave sign