title: Kinematic analysis of stair climbing in rotating platform cruciate-retaining and posterior-stabilized mobile-bearing total knee arthroplasties.
abstract: BACKGROUND
  The aim of our study was to compare and contrast the effects of two types of mobile-bearing total knee arthroplasties (TKA), namely, the cruciate-retaining (CR) and posterior-stabilized (PS) TKAs, on clinical outcomes and in vivo kinematics during stair climbing.
  
  
  METHODS
  The Press-Fit Condylar Sigma rotating platform was used for both CR and PS TKAs. Patient-reported outcomes were assessed using the 2011 Knee Society Score. Quadriceps muscle strength was evaluated by isokinetic dynamometry. In vivo kinematics were evaluated using periodic sagittal plane radiographic images obtained during stair climbing to quantify anteroposterior (AP) tibiofemoral translation, implant flexion and axial rotation angles using image-matching techniques. Outcomes were evaluated in 20 TKAs, which had been undergone with clinical success, including ten knees with CR types and ten knees with PS types.
  
  
  RESULTS
  There were no significant differences between the CR and PS TKA groups (p > 0.05) in isometric extensor torque (1.0 ± 0.2 and 1.1 ± 0.6 N m/kg, respectively) or patient-reported score for stair climbing function (4.0 ± 0.5 and 3.8 ± 0.9, respectively). Both types of TKAs showed stable AP translation in the mid range of knee flexion and paradoxical translation in the low range of flexion, with limited rotation, during stair climbing. There were no significant differences between the CR and PS TKA groups (P > 0.05) in anterior translation from 80° to 40° of knee flexion (4.2 ± 1.2 and 3.5 ± 1.6 mm, respectively), posterior translation from 40° to 10° of knee flexion (2.3 ± 1.9 and 2.0 ± 1.5 mm, respectively), and total external rotation (2.8° ± 4.9° and 0.5° ± 5.0°, respectively).
  
  
  CONCLUSIONS
  Both CR and PS types of rotating platform mobile-bearing TKAs provided reproducible knee joint kinematics during stair climbing and equivalent clinical outcomes.
  
  
  METHODS
  IV.
authors.affiliation: Department of Orthopaedic Surgery, Faculty of Medical Sciences, Kyushu University, 1-3-3 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Murakami
authors.affiliation: Department of Orthopaedic Surgery, Faculty of Medical Sciences, Kyushu University, 1-3-3 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan. hamachan@ortho.med.kyushu-u.ac.jp.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Hamai
authors.affiliation: Department of Orthopaedic Surgery, Faculty of Medical Sciences, Kyushu University, 1-3-3 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.|Katai Orthopaedic Hospital, 132-1 Okuma Kasuya-machi, Kasuya-gun, Fukuoka, 811-2302, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Okazaki
authors.affiliation: Department of Biorobotics, Faculty of Engineering, Kyushu Sangyo University, 2-3-1 Matsugadai, Higashi-ku, Fukuoka, 813-8583, Japan.
authors.forename: Satoru
authors.initials: S
authors.lastname: Ikebe
authors.affiliation: Department of Orthopaedic Surgery, Faculty of Medical Sciences, Kyushu University, 1-3-3 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Nakahara
authors.affiliation: Department of Biorobotics, Faculty of Engineering, Kyushu Sangyo University, 2-3-1 Matsugadai, Higashi-ku, Fukuoka, 813-8583, Japan.
authors.forename: Hidehiko
authors.initials: H
authors.lastname: Higaki
authors.affiliation: Department of Information and Systems Engineering, Faculty of Information Engineering, Fukuoka Institute of Technology, 3-30-1 Wajiro-higashi, Higashi-ku, Fukuoka, 811-0295, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Shimoto
authors.affiliation: Department of Orthopaedic Surgery, Faculty of Medical Sciences, Kyushu University, 1-3-3 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Mizu-Uchi
authors.affiliation: Department of Orthopaedic Surgery, Faculty of Medical Sciences, Kyushu University, 1-3-3 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
authors.forename: Umito
authors.initials: U
authors.lastname: Kuwashima
authors.affiliation: Department of Orthopaedic Surgery, Faculty of Medical Sciences, Kyushu University, 1-3-3 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
authors.forename: Yukihide
authors.initials: Y
authors.lastname: Iwamoto
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods; D001696:Biomechanical Phenomena / Q000502:physiology; D005260:Female; D006801:Humans; D007564:Japan; D007719:Knee Joint / Q000503:physiopathology / Q000601:surgery; D007720:Knee Prosthesis; D008297:Male; D053580:Muscle Strength / Q000502:physiology; D053581:Muscle Strength Dynamometer; D052097:Quadriceps Muscle / Q000503:physiopathology*; D016059:Range of Motion, Articular; D000072799:Stair Climbing / Q000502:physiology*
keywords: Image-matching techniques; Knee joint kinematics; Mobile-bearing total knee arthroplasty; Stair climbing; Total knee arthroplasty