title: Changes in knee kinematics following total knee arthroplasty.
abstract: Total knee arthroplasty (TKA) changes the knee joint in both intentional and unintentional, known and unknown, ways. Patellofemoral and tibiofemoral kinematics play an important role in postoperative pain, function, satisfaction and revision, yet are largely unknown. Preoperative kinematics, postoperative kinematics or changes in kinematics may help identify causes of poor clinical outcome. Patellofemoral kinematics are challenging to record since the patella is obscured by the metal femoral component in X-ray and moves under the skin. The purpose of this study was to determine the kinematic degrees of freedom having significant changes and to evaluate the variability in individual changes to allow future study of patients with poor clinical outcomes. We prospectively studied the 6 degrees of freedom patellofemoral and tibiofemoral weightbearing kinematics, tibiofemoral contact points and helical axes of rotation of nine subjects before and at least 1 year after total knee arthroplasty using clinically available computed tomography and radiographic imaging systems. Normal kinematics for healthy individuals were identified from the literature. Significant differences existed between pre-TKA and post-TKA kinematics, with the post-TKA kinematics being closer to normal. While on average the pre-total knee arthroplasty knees in this group displayed no pivoting (only translation), individually only five knees displayed this behaviour (of these, two showed lateral pivoting, one showed medial pivoting and one showed central pivoting). There was considerable variability postoperatively as well (five central, two lateral and two medial pivoting). Both preop and postop, flexion behaviour was more hinge-like medially and more rolling laterally. Helical axes were more consistent postop for this group. An inclusive understanding of the pre-TKA and post-TKA kinematics and changes in kinematics due to total knee arthroplasty could improve implant design, patient diagnosis and surgical technique.
authors.affiliation: Biomedical Engineering, University of Calgary, Calgary, AB, Canada McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, AB, Canada moaksh@gmail.com.
authors.forename: Mohsen
authors.initials: M
authors.lastname: Akbari Shandiz
authors.affiliation: Biomedical Engineering, University of Calgary, Calgary, AB, Canada.
authors.forename: Paul
authors.initials: P
authors.lastname: Boulos
authors.affiliation: Biomedical Engineering, University of Calgary, Calgary, AB, Canada McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, AB, Canada.
authors.forename: Stefan Karl
authors.initials: SK
authors.lastname: Saevarsson
authors.affiliation: Biomedical Engineering, University of Calgary, Calgary, AB, Canada.
authors.forename: Sam
authors.initials: S
authors.lastname: Yoo
authors.affiliation: McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, AB, Canada Department of Orthopaedic Surgery, University of Calgary, Calgary, AB, Canada.
authors.forename: Stephen
authors.initials: S
authors.lastname: Miller
authors.affiliation: Biomedical Engineering, University of Calgary, Calgary, AB, Canada McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, AB, Canada Department of Civil Engineering, University of Calgary, Calgary, AB, Canada.
authors.forename: Carolyn
authors.initials: C
authors.lastname: Anglin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D001696:Biomechanical Phenomena / Q000502:physiology*; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology* / Q000601:surgery; D007867:Leg Bones / Q000503:physiopathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D016059:Range of Motion, Articular / Q000502:physiology*
keywords: Total knee arthroplasty; helical axis of rotation; knee kinematics; patellofemoral; tibiofemoral; tibiofemoral contact point