title: In vivo movement of femoral flexion axis of a single-radius total knee arthroplasty.
abstract: The objective of this study was to investigate in vivo femoro-tibial motion using the movement of femoral flexion axis of a single-radius TKA. We examined 20 clinically successful knees with a single-radius posterior stabilized TKA to evaluate the kinematics of deep knee flexion using 2-3-dimensional registration techniques. The mean knee flexion range of motion was 117.8°. The mean rotation of the femoral component was 7.6° external rotation. The mean knee flexion angle at initial post-cam engagement was 55.2°. No paradoxical movement of femoral component was shown until 70° flexion, afterward the femoral component rolled back with flexion. The data showed that the design of this prosthesis might contribute to reduce the paradoxical anterior femoral movement and provide stability in mid-flexion ranges.
authors.affiliation: Department of Orthopaedic Biomaterial Science, Graduate School of Medicine, Suita, Osaka, Japan.
authors.forename: Norimasa
authors.initials: N
authors.lastname: Shimizu
authors.affiliation: Department of Orthopaedic Biomaterial Science, Graduate School of Medicine, Suita, Osaka, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Tomita
authors.affiliation: Center for Advanced Medical Engineering and Informatics, Graduate School of Medicine, Suita, Osaka, Japan.
authors.forename: Takaharu
authors.initials: T
authors.lastname: Yamazaki
authors.affiliation: Department of Orthopaedics, Osaka University, Graduate School of Medicine, Suita, Osaka, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Yoshikawa
authors.affiliation: Department of Orthopaedic Biomaterial Science, Graduate School of Medicine, Suita, Osaka, Japan.
authors.forename: Kazuomi
authors.initials: K
authors.lastname: Sugamoto
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001172:Arthritis, Rheumatoid / Q000503:physiopathology / Q000601:surgery; D019645:Arthroplasty, Replacement, Knee / Q000295:instrumentation* / Q000379:methods; D001696:Biomechanical Phenomena; D005260:Female; D005269:Femur / Q000503:physiopathology* / Q000601:surgery; D006801:Humans; D007719:Knee Joint / Q000601:surgery*; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D009068:Movement; D020370:Osteoarthritis, Knee / Q000503:physiopathology / Q000601:surgery*; D011474:Prosthesis Design; D016059:Range of Motion, Articular; D012399:Rotation; D013977:Tibia / Q000503:physiopathology / Q000601:surgery
keywords: femoral roll back; kinematics; paradoxical movement; posterior stabilized; single-radius TKA