title: A new distraction arthroplasty device using magnetic force; a cadaveric study.
abstract: BACKGROUND
  It is difficult for an articular cartilage injury to repair spontaneously. There are many procedures for treating cartilage injury, however there is no standard procedure for middle-aged patients who have diffuse knee osteoarthritis, especially of the lateral compartment. Therefore, Ochi developed a new distraction device that uses magnetic power to enlarge a joint space and promote cartilage regeneration with microfracture. The purpose of this study is to evaluate this new distraction arthroplasty system by using the cadaveric knee.
  
  
  METHODS
  This study used ten knees from six cadavers that were embalmed by Thiel's methods. The medial and lateral joint space was measured by AP radiographic view before and after distraction, and after weight-bearing to evaluate the joint distraction. The contact pressure of the medial and lateral compartments at the knee extension position by using a prescale film system was measured before and after weight-bearing with a 15 or 30-kg weight-bearing load to evaluate the effectiveness of this device.
  
  
  RESULTS
  The lateral joint space significantly increased from the pre-distraction to the post-distraction; however, it did not change significantly between post-distraction and post-weight-bearing. With a 15 or 30-kg weight-bearing load, the contact pressure of the lateral compartment significantly decreased from the pre-distraction to the post-distraction.
  
  
  CONCLUSIONS
  The most important advantage of this device is that it maintains a continuous distraction tension and enables almost the full range of motion of the knee. We believe that joint distraction by using magnetic force can be a promising option for cartilage injury in middle-aged patients.
authors.affiliation: Department of Orthopaedic surgery, Graduated School of Biomedical Science, Hiroshima University, Japan. go_k_0127@yahoo.co.jp
authors.forename: Goki
authors.initials: G
authors.lastname: Kamei
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Ochi
authors.forename: Atsushi
authors.initials: A
authors.lastname: Okuhara
authors.forename: Mineko
authors.initials: M
authors.lastname: Fujimiya
authors.forename: Masataka
authors.initials: M
authors.lastname: Deie
authors.forename: Nobuo
authors.initials: N
authors.lastname: Adachi
authors.forename: Atsuo
authors.initials: A
authors.lastname: Nakamae
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Nakasa
authors.forename: Shingo
authors.initials: S
authors.lastname: Ohkawa
authors.forename: Kobun
authors.initials: K
authors.lastname: Takazawa
authors.forename: Akio
authors.initials: A
authors.lastname: Eguchi
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Katou
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Takada
authors.forename: Muhammad Andry
authors.initials: MA
authors.lastname: Usman
mesh_terms: D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000295:instrumentation* / Q000379:methods; D054544:Arthroplasty, Subchondral / Q000295:instrumentation* / Q000379:methods; D002102:Cadaver; D002358:Cartilage, Articular / Q000000981:diagnostic imaging / Q000293:injuries / Q000601:surgery*; D004867:Equipment Design; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery; D008280:Magnetics; D008297:Male; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery; D011859:Radiography; D016059:Range of Motion, Articular; D014741:Video Recording; D016474:Weight-Bearing