Patellar tracking during total knee arthroplasty: an in vitro feasibility study

Area of Science:

• Orthopedic Surgery
• Biomechanical Engineering
• Medical Device Technology

Background:

• Abnormal patellar tracking is a significant cause of patello-femoral (PF) joint disorders and total knee arthroplasty (TKA) failure.
• Intra-operative assessment of patellar tracking during TKA is fundamental for successful outcomes.
• Current TKA procedures may not fully restore normal PF joint kinematics.

Purpose of the Study:

• To evaluate the feasibility of a novel 3D anatomical-based patellar tracking technique during standard TKA procedures.
• To assess the intra-operative assessment of patellar tracking for improved TKA outcomes.

Main Methods:

• Utilized a surgical navigation system with a custom-designed tracking device and reference frame for in-vitro analysis.
• Defined anatomical reference frames for femur, tibia, and patella using landmark digitization.
• Recorded passive knee flexion with quadriceps force before and after TKA, calculating PF and tibio-femoral (TF) joint kinematics.

Main Results:

• Observed repeatable and coupled motion paths for both TF and PF joints in intact knees during flexion-extension.
• Demonstrated that the replaced knee did not fully replicate the original PF motion of the intact knee.
• Calculated patellar flexion, tilt, rotation, and shift, alongside standard TF joint kinematics.

Conclusions:

• The study confirms the feasibility and necessity of intra-operative patellar tracking in TKA.
• Monitoring PF kinematics during TKA provides surgeons with enhanced prediction of final implant performance.
• This technique offers valuable support for critical surgical decisions in TKA.