title: Differences in knee joint kinematics and forces after posterior cruciate retaining and stabilized total knee arthroplasty.
abstract: BACKGROUND
  Posterior cruciate ligament (PCL) retaining (CR) and -sacrificing (PS) total knee arthroplasties (TKA) are widely-used to treat osteoarthritis of the knee joint. The PS design substitutes the function of the PCL with a cam-spine mechanism which may produce adverse changes to joint kinematics and kinetics.
  
  
  METHODS
  CR- and PS-TKA were performed on 11 human knee specimens. Joint kinematics were measured with a dynamic knee simulator and motion tracking equipment. In-situ loads of the PCL and cam-spine were measured with a robotic force sensor system. Partial weight bearing flexions were simulated and external forces were applied.
  
  
  RESULTS
  The PS-TKA rotated significantly less throughout the whole flexion range compared to the CR-TKA. Femoral roll back was greater in the PS-TKA; however, this was not correlated with lower quadriceps forces. Application of external loads produced significantly different in-situ force profiles between the TKA systems.
  
  
  CONCLUSIONS
  Our data demonstrate that the PS-design significantly alters kinematics of the knee joint. Our data also suggest the cam-spine mechanism may have little influence on high flexion kinematics (such as femoral rollback) with most of the load burden shared by supporting implant and soft-tissue structures.
authors.affiliation: Department of Orthopaedic Surgery, University Hospital Tübingen, Hoppe-Seyler-Str. 3, 72076 Tübingen, Germany. Electronic address: Markus.Wuenschel@uni-tuebingen.de.
authors.forename: Markus
authors.initials: M
authors.lastname: Wünschel
authors.forename: Jeremi M
authors.initials: JM
authors.lastname: Leasure
authors.forename: Philipp
authors.initials: P
authors.lastname: Dalheimer
authors.forename: Nicole
authors.initials: N
authors.lastname: Kraft
authors.forename: Nikolaus
authors.initials: N
authors.lastname: Wülker
authors.forename: Otto
authors.initials: O
authors.lastname: Müller
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D001696:Biomechanical Phenomena; D002102:Cadaver; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D059351:Organ Sparing Treatments; D016119:Posterior Cruciate Ligament / Q000601:surgery; D016059:Range of Motion, Articular / Q000502:physiology*; D012371:Robotics / Q000379:methods*; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical; D013718:Tensile Strength; D016474:Weight-Bearing
keywords: Arthroplasty; Forces; Kinematics; Knee joint; Robotics