Kinematic alignment produces near-normal knee motion but increases contact stress after total knee arthroplasty: A case study on a single implant design

Abstract

These findings suggest that kinematically aligned TKA produces near-normal knee kinematics, but that concerns for long-term outcome might arise because of high contact stresses.

Comparison of Kinematic and Mechanical Alignment Techniques in Primary Total Knee Arthroplasty: A Meta-Analysis

“…[31] In addition, 1 study comparing the kinematics and contact stresses between the KA and MA techniques through computer simulation and finite element analysis found that the peak contact stresses with 5°varus tilt of the tibial component were associated with greater tibiofemoral contact stress than 3°v arus tilt or neutral alignment of the tibial component at all flexion angles. [32] Our meta-analysis revealed a significant difference between the KA and MA techniques in radiographic parameters, including the TCRTMA, one of the most important parameters for assessing the clinical failure of polyethylene, suggesting that the tibial component was placed in a slightly more varus (2.25°) position with the KA technique than the MA technique. The discrepancy between the results of this metaanalysis and earlier studies may have arisen because the TCRTMA with the KA technique was less varus than expected, and because the KA technique now has patient-specific instruments and improvements in fixation and surgical techniques that diminish the risk of excessive varus tilt of the tibial components and restore the 3 functional kinematic axes.…”

Coronal alignment after total knee arthroplasty

“…Ishikawa et al, in a recent computer simulator and finite element analysis, found near-normal knee kinematics in kinematically-aligned TKAs; however, both patellofemoral and tibiofemoral peak contact stresses were increased by as much as 200% and 270% respectively in the kinematically-aligned model. 41 Furthermore, the accuracy of the patient-specific instrumentation systems typically required to achieve kinematic alignment are still being investigated 42,43 and may be inferior to traditional or navigated systems. 44 …”

A prospective double-blinded randomised control trial comparing robotic arm-assisted functionally aligned total knee arthroplasty versus robotic arm-assisted mechanically aligned total knee arthroplasty

“…Objectives The primary objective of this study is to compare the total Western Ontario and McMaster Universities Arthritis Index (WOMAC) score in MA TKA versus FA TKA at 2 years after surgery. As FA TKA enables improved restoration of native, patient-specific knee kinematics [15,26,29], the study hypothesis is that total WOMAC scores will be superior in patients undergoing FA TKA compared to MA TKA at 2 years follow-up.…”

“…Patient-specific implants, computer navigation and threedimensional printed cutting blocks have been used to help achieve kinematic alignment in TKA. Studies have demonstrated that TKA with kinematic alignment reproduces more natural knee kinematics including medial pivot movement and femoral rollback compared to MA TKA [14,34,15,26,29]. Preserving patient-specific alignment and knee kinematics in TKA with kinematic alignment may also decrease the risk of common peroneal nerve palsy, which is associated with forcing the limb into neutral alignment with extensive bone resections and periarticular releases in MA TKA [23,25].…”