title: The Posterior Condylar Cartilage Affects Rotational Alignment of the Femoral Component in Varus Knee Osteoarthritis.
abstract: Rotational alignment of the femoral component in total knee arthroplasty (TKA) is important for patellar tracking and ligament balance. Preoperative planning based on radiography might have a potential risk for over-rotation because these X-ray based measurements can not detect asymmetric cartilage wear on posterior condyle. The purpose of this study is to evaluate the effect of the posterior condylar cartilage of varus osteoarthritic knee on rotational alignment of the femoral component in TKA. We established two different condylar twist angles (CTA) from intraoperative multiplanar reconstruction (MPR) images and intraoperative information of navigation system. The CTA measured by a navigation system that includes the cartilage (4.8±2.0°) was smaller than those measured by MPR images, which does not include the cartilage (6.6±2.1°) (p<0.05). The difference between these two angles that corresponds to the remaining posterior condylar cartilage was 1.7±1.2°. This result demonstrated that the posterior condylar cartilage might lead to over-rotational of the femoral component in varus osteoarthritic knee. Therefore, when determining rotational alignment of the femoral component, surgeons should consider the effect of the remaining posterior condylar cartilage to avoid the over-rotation of the femoral component, especially in severe varus knees. J. Med. Invest. 64: 24-29, February, 2016.
authors.affiliation: Department of Orthopedics, Institute of Biomedical Sciences, University of Tokushima Graduate School.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Hamada
authors.forename: Keizo
authors.initials: K
authors.lastname: Wada
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Mikami
authors.forename: Shunichi
authors.initials: S
authors.lastname: Toki
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Goto
authors.forename: Takahiko
authors.initials: T
authors.lastname: Tsutsui
authors.forename: Tomoya
authors.initials: T
authors.lastname: Takasago
authors.forename: Akihiro
authors.initials: A
authors.lastname: Nagamachi
authors.forename: Koichi
authors.initials: K
authors.lastname: Sairyo
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D002358:Cartilage, Articular / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D005471:Fluoroscopy / Q000379:methods; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D012399:Rotation