Combined Rotational Alignment Change after Total Knee Arthroplasty in Different Tibial Component Designs:...

Area of Science:

• Orthopedic surgery
• Biomechanical engineering
• Medical imaging

Background:

• Component rotational alignment is critical for successful total knee arthroplasty (TKA) outcomes.
• Understanding the impact of tibial component design on rotational alignment is essential for improving surgical techniques.

Purpose of the Study:

• To measure combined rotational alignment change (ΔCR) after TKA.
• To compare the influence of symmetric versus asymmetric tibial component designs on ΔCR.

Main Methods:

• Eighty-four patients undergoing TKA were analyzed.
• Computed tomography (CT) scans were used to measure rotational alignment pre- and post-operatively.
• Correlation between isolated tibial component rotation (ITR) and ΔCR was assessed.

Main Results:

• Both symmetric and asymmetric tibial components resulted in internal lower limb rotation post-TKA.
• Asymmetric components showed a greater mean internal rotation (-4.8°) compared to symmetric components (-0.1°).
• A statistically significant correlation was found between ITR and tibial component rotation relative to the tibial tuberosity.

Conclusions:

• Asymmetric tibial components are more effective than symmetric ones in achieving the desired internal rotational alignment after TKA.
• Internal rotation of symmetric components relative to the tibial tuberosity should ideally be within 20° for correcting external deformities.
• Optimizing rotational alignment with appropriate component selection can enhance TKA results.