Kinematic Comparison between Medially Congruent and Posterior-Stabilized Third-Generation TKA Designs

Area of Science:

• Orthopedic surgery
• Biomechanics
• Biomedical engineering

Background:

• Comparison of medially congruent (MC) and posterior-stabilized (PS) total knee arthroplasty (TKA) designs.
• Evaluation of knee kinematics in patients with successful clinical outcomes post-TKA.
• Assessment of modern TKA designs' ability to replicate natural knee function.

Purpose of the Study:

• To compare knee kinematics between MC and PS TKA groups.
• To identify differences in specific kinematic parameters.
• To evaluate the reproduction of normal knee function by modern TKA designs.

Main Methods:

• 3D knee kinematics analysis using a multicamera optoelectronic system and force platform.
• Evaluation of ten TKA patients (4 PS, 6 MC) with successful outcomes.
• Measurement of knee flexion, adduction, and rotation angles during walking, compared to healthy controls.

Main Results:

• No significant differences in walking speed between MC and PS groups.
• PS group exhibited greater knee flexion at heel-strike and higher peak midstance knee flexion.
• PS group showed increased knee adduction fluctuations and higher peak knee flexion moments compared to MC.
• MC group demonstrated less peak internal rotation moments than the PS group.

Conclusions:

• Modern third-generation TKA designs do not fully restore normal knee kinematics.
• MC knees demonstrated a more natural kinematic pattern during heel-strike and axial rotation.
• PS knees showed improved kinematics during the mid-flexion phase of the gait cycle.