In vivo kinematic comparison between mobile-bearing and fixed-bearing total knee arthroplasty during step-up activity.
Mobile-bearing total knee arthroplasty (TKA) expects high conformity and low contact stress. It is designed to correct the rotational mismatch between femoral and tibial components. We examined the difference in weight-bearing knee kinematics in patients with mobile-bearing and fixed-bearing TKA performing step-up activities. We randomly assigned 40 knees (37 patients) to mobile-bearing TKA (n=20) or fixed-bearing TKA (n=20). Using fluoroscopic imaging we evaluated knee kinematics during step-up activity one year after surgery. The total extent of rotation was not different for the two TKAs. Due to the axial rotation of the polyethylene insert, patients with mobile-bearing TKA had a wider range of absolute axial rotation. The position of the medial and the lateral condyles was significantly more posterior in the fixed-bearing TKA. There were only minor kinematic differences between the two TKAs. The polyethylene insert in the mobile-bearing TKA moved as designed especially with respect to the self-alignment feature.
Department of Orthopaedic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
Nobukazu
N
Okamoto
Department of Orthopaedic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
Eiichi
E
Nakamura
Department of Orthopaedic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
Hiroaki
H
Nishioka
Department of Orthopaedic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
Tatsuki
T
Karasugi
Department of Orthopaedic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
Tatsuya
T
Okada
Department of Orthopaedic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
Hiroshi
H
Mizuta
D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000295:instrumentation*; D001696:Biomechanical Phenomena; D005260:Female; D005471:Fluoroscopy; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery; D007720:Knee Prosthesis; D008297:Male; D020370:Osteoarthritis, Knee / Q000503:physiopathology / Q000601:surgery*; D011446:Prospective Studies; D011474:Prosthesis Design; D016059:Range of Motion, Articular; D012399:Rotation; D016474:Weight-Bearing
fixed-bearing; kinematics; mobile-bearing; total knee arthroplasty