KINEMATICS AND CONTACT PATTERNS BEFORE AND AFTER TKA: AN IN VITRO COMPARISON OF MEDIAL STABILISED VS. POSTERIOR STABILISED DESIGN

IntroductionDespite consequent advancement in Total Knee Arthroplasty (TKA) up to 20% of patients are not satisfied after having been operated. Beside correct implantation, the design of the TKA-system is supposed to be a key factor of a successful TKA. Consequently it has been tried to restore natural kinematics by the design of the prosthesis. A medially stabilized design therefore is supposed to allow a lateral translation with a medial pivot.ObjectivesOur study compared posterior stabilized (PS) with medially stabilized (MS) TKA-design in terms of kinematics, femorotibial and patellofemoral contact patterns in vitro.MethodsTwelve fresh frozen human knee specimen (8 male, 4 female, O 63.9 y) were tested in a knee rig under natural condition and after TKA with the two different types of TKA systems (GMK PS; GMK MS Sphere; Medacta International, Switzerland). The knee rig simulated a loaded squat from approximately 20°−120° of flexion with a ground reaction force of 50 N. An ultrasound 3D-motion analysis...