title: Anteroposterior translation does not correlate with knee flexion after total knee arthroplasty.
abstract: BACKGROUND
  Stiffness after a TKA can cause patient dissatisfaction and diminished function, therefore it is important to characterize predictors of ROM after TKA. Studies of AP translation in conscious individuals disagree whether AP translation affects maximum knee flexion angle after implantation of a highly congruent sphere and trough geometry PCL-substituting prosthesis in a TKA.
  
  
  OBJECTIVE
  We investigated whether AP translation correlated with maximum knee flexion angle (1) in patients who were awake, and (2) who were under anesthesia (to minimize the effects of voluntary muscle contraction) in a TKA with implantation of a PCL-substituting mobile-bearing prosthesis.
  
  
  METHODS
  AP translation was examined under both conditions in 34 primary TKAs. Measurements under anesthesia were performed when the patients were having anesthesia for a contralateral TKA. Awake measurements were made within 4 days of that anesthetic session in patients who had no residual sedative effects. The average postoperative interval for the index TKA flexion measurements was 23 months (range, 6-114 months). AP translation was evaluated at 75° flexion using an arthrometer.
  
  
  RESULTS
  There was no correlation between postoperative maximum knee flexion and AP translation at 75° during consciousness. There was no correlation between postoperative maximum knee flexion and AP translation under anesthesia.
  
  
  CONCLUSIONS
  AP translation at 75° flexion did not correlate with postoperative maximum knee flexion in either awake or anesthetized patients during a TKA with implantation of a posterior cruciate-substituting prosthesis.
authors.affiliation: Ishii Orthopaedic and Rehabilitation Clinic, 1089 Shimo-Oshi, Gyoda, Saitama, 361-0037, Japan, ishii@sakitama.or.jp.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Ishii
authors.forename: Hideo
authors.initials: H
authors.lastname: Noguchi
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Takeda
authors.forename: Junko
authors.initials: J
authors.lastname: Sato
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Toyabe
mesh_terms: D000368:Aged; D000768:Anesthesia, General; D019645:Arthroplasty, Replacement, Knee / Q000295:instrumentation; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology / Q000601:surgery*; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D016119:Posterior Cruciate Ligament / Q000503:physiopathology / Q000601:surgery; D011446:Prospective Studies; D011474:Prosthesis Design; D016059:Range of Motion, Articular; D020127:Recovery of Function; D013997:Time Factors; D016896:Treatment Outcome; D014851:Wakefulness