title: Physiologically shaped knee arthroplasty induces natural roll-back.
abstract: After total knee replacement the persistence of pain represents a significant problem. In this study, a novel knee arthroplasty (Aequos G1 knee arthroplasty) is investigated that was designed to replicate main features of human knee morphology to reduce the periodically occurring pain after knee replacement. Previous work showed theoretically that this arthroplasty design may reconstruct the four-bar linkage mechanism as it occurs in human knee by contriving a convex lateral tibial compartment and a sagittal offset of the centre of the medial and lateral femur condyles - inducing a roll-back mechanism as it exists in human. The aim of this study was to determine whether this potential roll-back mechanism can be confirmed by in-vivo measurements. This retrospective study showed that the patellar tendon angle decreases during flexion of 0.21° per degree of flexion on average in the 16 knees studied. This amount is similar to physiological knee kinematics and in contrast to existing results in the literature after implantation of conventional total knee replacements which lack physiological knee kinematics. The results suggest that physiological motion after implantation of the Aequos G1 knee arthroplasty occurs during loaded motion up to approximately 45° knee flexion.
authors.affiliation: Department of Trauma Surgery, Plastic and Reconstructive Surgery, Georg-August-University, Goettingen, Germany. Thilo.Floerkemeier@ddhgruppe.de
authors.forename: Thilo
authors.initials: T
authors.lastname: Floerkemeier
authors.forename: Karl-Heinz
authors.initials: KH
authors.lastname: Frosch
authors.forename: Martin
authors.initials: M
authors.lastname: Wachowski
authors.forename: Dietmar
authors.initials: D
authors.lastname: Kubein-Meesenburg
authors.forename: Riccardo
authors.initials: R
authors.lastname: Gezzi
authors.forename: Jochen
authors.initials: J
authors.lastname: Fanghänel
authors.forename: Klaus Michael
authors.initials: KM
authors.lastname: Stürmer
authors.forename: Hans
authors.initials: H
authors.lastname: Nägerl
mesh_terms: D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000502:physiology* / Q000601:surgery; D007720:Knee Prosthesis; D008297:Male; D020370:Osteoarthritis, Knee / Q000473:pathology / Q000601:surgery*; D010146:Pain / Q000209:etiology / Q000517:prevention & control; D011474:Prosthesis Design; D012189:Retrospective Studies