title: Biomechanical effects of total knee arthroplasty component malrotation: a computational simulation.
abstract: Modern total knee arthroplasty (TKA) is an effective procedure to treat pain and disability due to osteoarthritis, but some patients experience quadriceps weakness after surgery and have difficulty performing important activities of daily living. The success of TKA depends on many factors, but malalignment of the prosthetic components is a major cause of postoperative complications. Significant variability is associated with femoral and tibial component rotational alignment, but how this variability translates into functional outcome remains unknown. We used a forward-dynamic computer model of a simulated squatting motion to perform a parametric study of the effects of variations in component rotational alignment in TKA. A cruciate-retaining and posterior-stabilized version of the same TKA implant were compared. We found that femoral rotation had a greater effect on quadriceps forces, collateral ligament forces, and varus/valgus kinematics, while tibial rotation had a greater effect on anteroposterior translations. Our findings support the tendency for orthopedic surgeons to bias the femoral component into external rotation and avoid malrotation of the tibial component.
authors.affiliation: Department of Mechanical and Aerospace Engineering, The Ohio State University, E305 Scott Laboratory, 201W 19th Ave, Columbus, Ohio 43210-1142, USA.
authors.forename: Julie A
authors.initials: JA
authors.lastname: Thompson
authors.forename: Michael W
authors.initials: MW
authors.lastname: Hast
authors.forename: Jeffrey F
authors.initials: JF
authors.lastname: Granger
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Piazza
authors.forename: Robert A
authors.initials: RA
authors.lastname: Siston
mesh_terms: D019645:Arthroplasty, Replacement, Knee; D001696:Biomechanical Phenomena / Q000502:physiology; D017885:Collateral Ligaments / Q000502:physiology; D003198:Computer Simulation; D005269:Femur / Q000502:physiology; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D008954:Models, Biological; D020370:Osteoarthritis, Knee / Q000503:physiopathology* / Q000601:surgery; D052097:Quadriceps Muscle / Q000502:physiology; D013977:Tibia / Q000502:physiology