title: Influence of Total Knee Arthroplasty on Patellar Kinematics and Patellofemoral Pressure.
abstract: Patellofemoral complications are one of the main problems after total knee arthroplasty (TKA). The design of the TKA component may affect the patellar biomechanics, which may be associated with this postoperative complication. The purpose of this study was to assess the influence of TKA and prosthesis designs on the patellar kinematics and patellofemoral pressure.
  
  
  
  Using fresh-frozen cadavers, we measured the patellofemoral pressure, patella offset, and patella tilt in the following 4 conditions: normal knee (patella replacement only), cruciate-retaining TKA, condylar-stabilizing TKA, and posterior-stabilized TKA.
  
  
  
  The patellofemoral pressure increased significantly after the cruciate-retaining TKA and condylar-stabilizing TKA compared with the normal knee. The patella offset in the normal knee decreased with increasing knee flexion angles, while the patella offset in the TKA knees did not change significantly through the full range of motion. The amount of lateral patella tilt in the normal knee was significantly larger than the TKA knees in the full range of motion.
  
  
  
  Although the femoral components are designed to reproduce an anatomical patellar tracking, the physiological patellar kinematics were not observed. Relatively high patellofemoral pressure and kinematic change after TKA may be associated with postoperative complications such as the anterior knee pain.
authors.affiliation: Department of Orthopaedic Surgery, Saitama City Hospital, Saitama-shi, Saitama-ken, Japan.
authors.forename: Hidenori
authors.initials: H
authors.lastname: Tanikawa
authors.affiliation: Digital Human Research Centre, National Institute of Advanced Industrial Science and Technology, Tokyo, Japan.
authors.forename: Mitsunori
authors.initials: M
authors.lastname: Tada
authors.affiliation: Department of Orthopaedic Surgery, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Kengo
authors.initials: K
authors.lastname: Harato
authors.affiliation: Department of Orthopaedic Surgery, Saitama City Hospital, Saitama-shi, Saitama-ken, Japan.
authors.forename: Kazunari
authors.initials: K
authors.lastname: Okuma
authors.affiliation: Department of Clinical Biomechanics, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Takeo
authors.initials: T
authors.lastname: Nagura
mesh_terms: D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology* / Q000601:surgery; D007720:Knee Prosthesis; D008297:Male; D010329:Patella / Q000503:physiopathology* / Q000601:surgery; D057071:Patellofemoral Joint / Q000503:physiopathology* / Q000601:surgery; D011312:Pressure; D011474:Prosthesis Design; D016059:Range of Motion, Articular / Q000502:physiology; D012092:Replantation
keywords: knee biomechanics; patellar kinematics; patellofemoral pressure; prosthesis design; total knee arthroplasty