title: Knee kinematics in medial osteoarthritis during in vivo weight-bearing activities.
abstract: Dynamic knee kinematics were analyzed for medial osteoarthritic (OA) knees in three activities, including two types of maximum knee flexion. Continuous x-ray images of kneeling, squatting, and stair climbing motions were taken using a large flat panel detector. CT-derived bone models were used for the model registration-based 3D kinematic measurements. Three-dimensional joint kinematics and contact locations were determined using two methods: bone-fixed coordinate systems and by interrogation of CT-based bone model surfaces. The femur exhibited gradual external rotation with knee flexion for kneeling and squatting activities, and gradual internal rotation with knee extension for stair climbing. From 100 degrees to 120 degrees flexion, contact locations showed a medial pivot pattern similar to normal knees. However, knees with medial OA displayed a femoral internal rotation bias and less posterior translation when compared with normal knees. A classic screw-home movement was not observed in OA knees near extension. Decreased variability with both activities and methods of calculation were demonstrated for all three activities. In conclusion, the weight-bearing kinematics of patients with medial OA differs from normal knees. Pathological changes of the articulating surfaces and the ligaments correspond to observed abnormalities in knee kinematics.
authors.affiliation: Department of Mechanical and Aerospace Engineering, University of Florida, 318 MAE-A, Mail Stop 116250, Gainesville, Florida 32611-6250, USA.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Hamai
authors.forename: Taka-Aki
authors.initials: TA
authors.lastname: Moro-oka
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Miura
authors.forename: Takeshi
authors.initials: T
authors.lastname: Shimoto
authors.forename: Hidehiko
authors.initials: H
authors.lastname: Higaki
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Fregly
authors.forename: Yukihide
authors.initials: Y
authors.lastname: Iwamoto
authors.forename: Scott A
authors.initials: SA
authors.lastname: Banks
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D015444:Exercise / Q000502:physiology; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000503:physiopathology*; D011187:Posture; D016059:Range of Motion, Articular / Q000502:physiology; D012399:Rotation; D014057:Tomography, X-Ray Computed; D016474:Weight-Bearing