title: In-vivo evaluation of the kinematic behavior of an artificial medial meniscus implant: A pilot study using open-MRI.
abstract: BACKGROUND
  In this pilot study we wanted to evaluate the kinematics of a knee implanted with an artificial polycarbonate-urethane meniscus device, designed for medial meniscus replacement. The static kinematic behavior of the implant was compared to the natural medial meniscus of the non-operated knee. A second goal was to evaluate the motion pattern, the radial displacement and the deformation of the meniscal implant.
  
  
  METHODS
  Three patients with a polycarbonate-urethane implant were included in this prospective study. An open-MRI was used to track the location of the implant during static weight-bearing conditions, within a range of motion of 0° to 120° knee flexion. Knee kinematics were evaluated by measuring the tibiofemoral contact points and femoral roll-back. Meniscus measurements (both natural and artificial) included anterior-posterior meniscal movement, radial displacement, and meniscal height.
  
  
  RESULTS
  No difference (P>0.05) was demonstrated in femoral roll-back and tibiofemoral contact points during knee flexion between the implanted and the non-operated knees. Meniscal measurements showed no significant difference in radial displacement and meniscal height (P>0.05) at all flexion angles, in both the implanted and non-operated knees. A significant difference (P ≤ 0.05) in anterior-posterior movement during flexion was observed between the two groups.
  
  
  CONCLUSIONS
  In this pilot study, the artificial polycarbonate-urethane implant, indicated for medial meniscus replacement, had no influence on femoral roll-back and tibiofemoral contact points, thus suggesting that the joint maintains its static kinematic properties after implantation. Radial displacement and meniscal height were not different, but anterior-posterior movement was slightly different between the implant and the normal meniscus.
authors.affiliation: Department of Radiology, Ghent University Hospital, De Pintelaan 185, B-9000 Ghent, Belgium. Electronic address: tineke.deconinck@ugent.be.
authors.forename: Tineke
authors.initials: T
authors.lastname: De Coninck
authors.affiliation: Active Implants Israel Ltd., R&D Department, 43 Hamelacha St., P.O. Box 8395, Netanya 42505, Israel. Electronic address: jon.elsner@activeimplants.com.
authors.forename: Jonathan J
authors.initials: JJ
authors.lastname: Elsner
authors.affiliation: Active Implants Israel Ltd., R&D Department, 43 Hamelacha St., P.O. Box 8395, Netanya 42505, Israel. Electronic address: eran.ganz@activeimplants.com.
authors.forename: Eran
authors.initials: E
authors.lastname: Linder-Ganz
authors.affiliation: Department of Orthopaedic Surgery and Traumatology, Ghent University Hospital, De Pintelaan 185, B-9000 Ghent, Belgium. Electronic address: michiel.cromheecke@gmail.com.
authors.forename: Michiel
authors.initials: M
authors.lastname: Cromheecke
authors.affiliation: Active Implants Israel Ltd., R&D Department, 43 Hamelacha St., P.O. Box 8395, Netanya 42505, Israel. Electronic address: maoz.shemesh@activeimplants.com.
authors.forename: Maoz
authors.initials: M
authors.lastname: Shemesh
authors.affiliation: Department of Radiology, Ghent University Hospital, De Pintelaan 185, B-9000 Ghent, Belgium. Electronic address: wouter.huysse@gmail.com.
authors.forename: Wouter
authors.initials: W
authors.lastname: Huysse
authors.affiliation: Department of Orthopaedic Surgery and Traumatology, Ghent University Hospital, De Pintelaan 185, B-9000 Ghent, Belgium. Electronic address: Rene.Verdonk@uzgent.be.
authors.forename: René
authors.initials: R
authors.lastname: Verdonk
authors.affiliation: Department of Radiology, Ghent University Hospital, De Pintelaan 185, B-9000 Ghent, Belgium. Electronic address: koenraad.verstraete@ugent.be.
authors.forename: Koenraad
authors.initials: K
authors.lastname: Verstraete
authors.affiliation: Department of Orthopaedic Surgery and Traumatology, Ghent University Hospital, De Pintelaan 185, B-9000 Ghent, Belgium; Antwerp Orthopedic Center, Monica Hospitals, Harmoniestraat 68, 2018 Antwerp, Belgium. Electronic address: pverdonk@yahoo.com.
authors.forename: Peter
authors.initials: P
authors.lastname: Verdonk
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D005260:Female; D005269:Femur; D006801:Humans; D007718:Knee Injuries / Q000601:surgery*; D007719:Knee Joint / Q000601:surgery; D007720:Knee Prosthesis; D008279:Magnetic Resonance Imaging; D008297:Male; D008592:Menisci, Tibial / Q000601:surgery*; D008875:Middle Aged; D010865:Pilot Projects; D011076:Polycarboxylate Cement / Q000737:chemistry; D011446:Prospective Studies; D019736:Prostheses and Implants; D016059:Range of Motion, Articular; D014520:Urethane / Q000737:chemistry; D016474:Weight-Bearing
chemical_list: D011076:Polycarboxylate Cement; C005506:polycarbonate; D014520:Urethane
keywords: Displacement; Kinematics; Meniscus; Open MRI; Polycarbonate-urethane implant