title: Comparisons of kinematics and range of motion in high-flexion total knee arthroplasty: cruciate retaining vs. substituting designs.
abstract: OBJECTIVE
  The purpose of this study was to compare in vivo kinematics, range of motion, and functional outcomes in patients that received either a high-flexion cruciate retaining or a high-flexion cruciate substituting knee.
  
  
  METHODS
  Forty-eight high-flexion cruciate retaining (CR) and 47 high-flexion cruciate substituting (PS) knees were included in this study and followed for an average of 27 months (24-33). Weight-bearing and non-weight-bearing maximal flexions and functional scores were compared between two groups. For kinematics evaluations, amount of posterior femoral roll-back and internal tibial rotation from 0° to maximal flexion using lateral radiographs under weight-bearing conditions were also compared.
  
  
  RESULTS
  Average weight-bearing maximal flexion was 126.3° in the PS group, which was significantly higher than the 115.0° in the CR group. Average functional scores showed no significant difference between the two groups. In terms of kinematics, the average amount of posterior femoral roll-back during full flexion was 9.6 mm in the PS group and 6.1 mm in the CR group, which was a significant difference. However, internal tibial rotation during full flexion was not significantly different in the two groups.
  
  
  CONCLUSIONS
  PS high-flexion TKA provided greater weight-bearing maximal flexion and posterior femoral roll-back than CR high-flexion TKA, although no difference in clinical outcomes was observed between the two prosthesis designs.
authors.affiliation: Department of Orthopaedic, Center for Joint Disease, Chonnam National University Hwasun Hospital, Jeonnam, South Korea.
authors.forename: Jong-Keun
authors.initials: JK
authors.lastname: Seon
authors.forename: Ju-Kwon
authors.initials: JK
authors.lastname: Park
authors.forename: Young-Joo
authors.initials: YJ
authors.lastname: Shin
authors.forename: Hyung-Yeon
authors.initials: HY
authors.lastname: Seo
authors.forename: Keun-Bae
authors.initials: KB
authors.lastname: Lee
authors.forename: Eun-Kyoo
authors.initials: EK
authors.lastname: Song
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016118:Anterior Cruciate Ligament / Q000503:physiopathology / Q000601:surgery; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D001696:Biomechanical Phenomena; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016119:Posterior Cruciate Ligament / Q000503:physiopathology / Q000601:surgery; D011446:Prospective Studies; D016059:Range of Motion, Articular / Q000502:physiology*; D020127:Recovery of Function; D018709:Statistics, Nonparametric; D016896:Treatment Outcome; D016474:Weight-Bearing