Willy Theodore1, Joshua Twiggs2, Elizabeth Kolos3, Justin Roe4, Brett Fritsch5, David Dickison6, David Liu7, Lucy Salmon4, Brad Miles8, Stephen Howell9. 1. School of Computer Science, Engineering and Mathematics, Flinders University, Adelaide, SA 5042, Australia. 2. Biomedical Engineering, AMME, University of Sydney, Sydney, NSW 2006, Australia. 3. Biomedical Engineering, AMME, University of Sydney, Sydney, NSW 2006, Australia. Electronic address: Elizabeth.kolos@hotmail.com. 4. North Sydney Orthopaedic and Sports Medicine Centre, The Mater Hospital, NSW, Australia. 5. North Shore Knee Clinic, NSW, Australia. 6. Peninsula Orthopaedic Research Institute, NSW, Australia. 7. Gold Coast Centre for Bone and Joint Surgery, Queensland, Australia. 8. 360 Knee Systems Pty Ltd, Suite 3 Building 1, 20 Bridge Street, Pymble, NSW 2073, Australia. 9. Department of Biomedical Engineering, University of California, Davis, Sacramento, CA 95817, USA.
Abstract
BACKGROUND: Total knee arthroplasty (TKA) significantly improves pain and restores a considerable degree of function. However, improvements are needed to increase patient satisfaction and restore kinematics to allow more physically demanding activities that active patients consider important. The aim of our study was to compare the alignment and motion of kinematically and mechanically aligned TKAs. METHODS: A patient specific musculoskeletal computer simulation was used to compare the tibio-femoral and patello-femoral kinematics between mechanically aligned and kinematically aligned TKA in 20 patients. RESULTS: When kinematically aligned, femoral components on average resulted in more valgus alignment to the mechanical axis and internally rotated to surgical transepicondylar axis whereas tibia component on average resulted in more varus alignment to the mechanical axis and internally rotated to tibial AP rotational axis. With kinematic alignment, tibio-femoral motion displayed greater tibial external rotation and lateral femoral flexion facet centre (FFC) translation with knee flexion than mechanical aligned TKA. At the patellofemoral joint, patella lateral shift of kinematically aligned TKA plateaued after 20 to 30° flexion while in mechanically aligned TKA it decreased continuously through the whole range of motion. CONCLUSIONS: Kinematic alignment resulted in greater variation than mechanical alignment for all tibio-femoral and patello-femoral motion. Kinematic alignment places TKA components patient specific alignment which depends on the preoperative state of the knee resulting in greater variation in kinematics. The use of computational models has the potential to predict which alignment based on native alignment, kinematic or mechanical, could improve knee function for patient's undergoing TKA.
BACKGROUND:Total knee arthroplasty (TKA) significantly improves pain and restores a considerable degree of function. However, improvements are needed to increase patient satisfaction and restore kinematics to allow more physically demanding activities that active patients consider important. The aim of our study was to compare the alignment and motion of kinematically and mechanically aligned TKAs. METHODS: A patient specific musculoskeletal computer simulation was used to compare the tibio-femoral and patello-femoral kinematics between mechanically aligned and kinematically aligned TKA in 20 patients. RESULTS: When kinematically aligned, femoral components on average resulted in more valgus alignment to the mechanical axis and internally rotated to surgical transepicondylar axis whereas tibia component on average resulted in more varus alignment to the mechanical axis and internally rotated to tibial AP rotational axis. With kinematic alignment, tibio-femoral motion displayed greater tibial external rotation and lateral femoral flexion facet centre (FFC) translation with knee flexion than mechanical aligned TKA. At the patellofemoral joint, patella lateral shift of kinematically aligned TKA plateaued after 20 to 30° flexion while in mechanically aligned TKA it decreased continuously through the whole range of motion. CONCLUSIONS: Kinematic alignment resulted in greater variation than mechanical alignment for all tibio-femoral and patello-femoral motion. Kinematic alignment places TKA components patient specific alignment which depends on the preoperative state of the knee resulting in greater variation in kinematics. The use of computational models has the potential to predict which alignment based on native alignment, kinematic or mechanical, could improve knee function for patient's undergoing TKA.
Authors: Kaushik Hazratwala; William B O'Callaghan; Shilpa Dhariwal; Matthew P R Wilkinson Journal: Knee Surg Sports Traumatol Arthrosc Date: 2021-09-06 Impact factor: 4.114
Authors: In Jun Koh; Il Jung Park; Charles C Lin; Nilay A Patel; Christen E Chalmers; Mauro Maniglio; Michelle H McGarry; Thay Q Lee Journal: Knee Surg Sports Traumatol Arthrosc Date: 2018-10-28 Impact factor: 4.342