title: [Kinematic analysis before and after bicondylar resurfacing knee arthroplasty].
abstract: Knee joint motion appears as a hinge movement around the flexion-extension axis. Corresponding to the rolling-sliding mechanism and alternative models of knee joint kinematics, an instant center pathway must be expected. The current photogrammetric investigation aimed to analyze these pathways when assessed in the sagittal plane in patients with preoperative varus or valgus deformity. A total of 40 patients either with varus or valgus deformity (20 in each group) were examined before and 6 months after implantation of PFC-SIGMA prostheses. Apart from the influence of knee joint deformity, a so-called soft tissue ratio was investigated. Therefore, the relation of thigh and femur as well as lower limb and tibia diameters was calculated and combined in one value. The investigation unit consisted of a standardized chair with passive knee joint movement (90-0 degrees flexion) supported by an electric motor. The position of predefined skin markers was assessed by digital camera with online transmission to a PC. The instant center pathway was then evaluated applying the Reuleaux technique based on the changes of skin marker positions. Results showed the following characteristics: small values of soft tissue ratio were represented by round or oval courses of the pathway whereas increasing ratios led to triangular and slightly increased dimensions of the courses. Varus deformity was primarily combined with an increase of the pathway's dimension and in contrast, valgus deformity showed decreased pathways. In each case, dimensions normalized after prosthesis implantation. The instant center pathway of knee joint motion showed for both patient groups characteristic phenomena. They were clearly associated with constitutional and clinical features of each patient.
authors.affiliation: Winghofer Medium, Rottenburg am Neckar. m.schwitalle@winghofer-medium.de
authors.forename: M
authors.initials: M
authors.lastname: Schwitalle
authors.forename: E M
authors.initials: EM
authors.lastname: Schwitalle
authors.forename: A
authors.initials: A
authors.lastname: Just
authors.forename: S
authors.initials: S
authors.lastname: Köller
authors.forename: T
authors.initials: T
authors.lastname: Mark
authors.forename: F
authors.initials: F
authors.lastname: Bodem
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee; D001696:Biomechanical Phenomena; D017760:Bone Malalignment / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D010780:Photogrammetry; D011183:Postoperative Complications / Q000000981:diagnostic imaging / Q000503:physiopathology*; D011474:Prosthesis Design; D011859:Radiography; D016059:Range of Motion, Articular / Q000502:physiology*; D012016:Reference Values
vernacular_title: Kinematische Analyse vor und nach bikondylärem Oberflächenersatz des Kniegelenks.