title: Evaluation of the size and position of the insertion of the anterior medial meniscus root in varus osteoarthritic knees.
abstract: OBJECTIVE
  Recent studies have suggested radial displacement of the medial meniscus as a cause of varus knee osteoarthritis (OA). Two anatomical studies reported that such displacement may be associated with anterior insertion of the medial meniscus anterior horn. It was aimed to evaluate the location and area of this insertion in patients with advanced knee OA.
  
  
  METHODS
  Medial meniscus anterior horn insertions were classified into four types, as described in a previously reported classification during 225 total knee arthroplasty (TKA) in 184 patients. The incidence rates of insertion type were compared with previously reported rates in nearly normal or non-arthritic knees. The insertion surface area was also measured during 158 TKAs.
  
  
  RESULTS
  Of the 225 knees, 82 (36.4 %), 93 (41.3 %), 35 (15.6 %), and 15 (6.7 %) were classified as I, II, III, and IV, respectively. An anteriorly inserted anterior horn was not more frequent in advanced varus OA knees than in previously reported nearly normal or non-arthritic knees. The insertion surface areas were 57.5 ± 18.9, 56.1 ± 16.0, and 56.4 ± 14.4 mm2for types I, II, and III, respectively; these areas did not differ significantly.
  
  
  CONCLUSIONS
  Since the incidence of an anteriorly inserted medial meniscus anterior horn was not higher in advanced varus OA knees than in normal or non-arthritic knees, an anteriorly inserted anterior horn may have little or no effect on the aetiology of varus OA knees. This study provides some information for clarifying the aetiology of knee OA.
  
  
  METHODS
  IV.
authors.affiliation: Department of Orthopaedic Surgery, Tohoku Orthopaedic Clinic, 4-9-22 Kamiyagari, Izumi-ku, Sendai City, 981-3121, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Sasaki
authors.affiliation: Department of Orthopaedic Surgery, Tohoku Orthopaedic Clinic, 4-9-22 Kamiyagari, Izumi-ku, Sendai City, 981-3121, Japan. t-sugita@tohokuseikei.com.
authors.forename: Takehiko
authors.initials: T
authors.lastname: Sugita
authors.affiliation: Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai City, 980-8574, Japan.
authors.forename: Toshimi
authors.initials: T
authors.lastname: Aizawa
authors.affiliation: Department of Orthopaedic Surgery, Tohoku Orthopaedic Clinic, 4-9-22 Kamiyagari, Izumi-ku, Sendai City, 981-3121, Japan.
authors.forename: Naohisa
authors.initials: N
authors.lastname: Miyatake
authors.affiliation: Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai City, 980-8574, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Kamimura
authors.affiliation: Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai City, 980-8574, Japan.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Fujisawa
authors.affiliation: Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai City, 980-8574, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Takahashi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee; D005260:Female; D056305:Genu Varum / Q000473:pathology* / Q000601:surgery; D006801:Humans; D007719:Knee Joint; D008297:Male; D008592:Menisci, Tibial / Q000473:pathology*; D008875:Middle Aged; D009929:Organ Size; D020370:Osteoarthritis, Knee / Q000473:pathology* / Q000601:surgery
keywords: Anterior horn; Insertion surface area; Medial meniscus; Radial displacement; Varus knee osteoarthritis