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Published on: July 2, 2021
In vivo patellar kinematics during total knee arthroplasty
Carolyn Anglin1, Karen C T Ho, Jean-Louis Briard
1Centre for Bioengineering Research & Education and Department of Civil Engineering, University of Calgary, Calgary, Alberta, Canada. canglin@ucalgary.ca
Summary
Total knee arthroplasty significantly alters patellar kinematics in vivo, potentially causing complications. A computer-assisted surgery system revealed changes in patellar positioning and tilt, highlighting the need for intraoperative awareness to improve outcomes.
Area of Science:
- Orthopedic Surgery
- Biomechanical Engineering
- Medical Imaging
Background:
- Patellar maltracking after total knee arthroplasty (TKA) is a common cause of anterior knee pain and instability.
- Factors influencing patellar kinematics include component placement, implant design, alignment, and soft tissue balance.
- Previous studies have not reported in vivo measurements of patellar kinematics following TKA.
Purpose of the Study:
- To measure and compare in vivo patellar kinematics before and after TKA using a computer-assisted surgery (CAS) system.
- To assess the impact of TKA on patellar positioning, tilt, and rotation.
- To identify potential factors influencing kinematic changes, such as tibial joint line shift and patient gender.
Main Methods:
- A novel CAS system was developed to track pre- and post-arthroplasty patellar kinematics in 18 patients across three centers.
- The system measured parameters including proximodistal and anteroposterior positioning, tilt, and rotation.
- Statistical analysis was performed to evaluate changes in kinematics and identify gender-specific differences.
Main Results:
- A mean proximal tibial joint line shift of 4.2 mm was observed, leading to a pseudo patella-baja.
- Significant changes in patellar positioning (proximodistal, anteroposterior) and flexion occurred (p < 0.008).
- Mediolateral shift, tilt, and rotation showed the largest changes, with no directional surgical bias. Female patients exhibited greater lateral tilt.
Conclusions:
- The CAS system is feasible for measuring in vivo patellofemoral kinematics during TKA.
- TKA significantly alters patellar kinematics, with tibial joint line position being a key factor.
- Intraoperative assessment of patellar tracking and tibiofemoral joint line is crucial for optimizing surgical plans and improving postoperative outcomes.
