Alignment philosophy influences trochlea recreation in total knee arthroplasty: a comparative study using image-based...

Area of Science:

• Orthopedic surgery
• Biomechanical engineering
• Robotic surgery

Background:

• Kinematic alignment (KA) is utilized in total knee arthroplasty (TKA) with the aim of recreating native anatomy.
• The effectiveness of KA in restoring the native trochlear groove, a critical component of knee anatomy, remains uncertain.

Purpose of the Study:

• To evaluate whether different femoral component alignment strategies in TKA impact the restoration of the native trochlear groove.
• To compare the ability of kinematic, mechanical, and functional alignment to recreate trochlear anatomy.

Main Methods:

• A retrospective analysis of 122 patients undergoing robotic-assisted TKA using the MAKO platform.
• Simulated femoral component placement according to kinematic, mechanical, and functional alignment principles.
• Assessment of trochlear groove restoration by measuring medial-lateral shift and depth at 0°, 30°-40°, and 70°-80° flexion.

Main Results:

• Significant differences in femoral alignment and trochlear groove restoration were observed across the alignment groups.
• Kinematic alignment resulted in the greatest lateral translation of the trochlear groove (6.40 ± 2.43 mm) compared to functional alignment (6.88 ± 1.74 mm) and mechanical alignment (7.84 ± 1.99 mm) at full extension.
• Functional alignment most accurately restored trochlear groove depth across all measured flexion angles.

Conclusions:

• Alignment philosophy significantly influences the recreation of the trochlear groove in TKA.
• Kinematic alignment led to potentially unsafe positioning in over 13% of cases.
• Functional alignment provided the closest restoration of trochlear groove depth throughout the range of motion.