How accurate is Whiteside's line as a reference axis in total knee arthroplasty?

Area of Science:

• Orthopedic Surgery
• Biomechanical Engineering
• Anatomy

Background:

• Computer-assisted surgery enhances precision in knee prosthesis insertion.
• Accurate rotational alignment of the femoral prosthesis is crucial for optimal outcomes in total knee arthroplasty.
• Traditional and computer-assisted techniques rely on precise identification of bony morphology for prosthesis orientation.

Purpose of the Study:

• To evaluate the reliability and reproducibility of Whiteside's line as a rotational reference axis.
• To assess the accuracy of Whiteside's line in relation to the epicondylar axis in cadaveric distal femora.
• To determine if Whiteside's line alone is sufficient for guiding femoral prosthesis rotation.

Main Methods:

• A cadaveric study involving 50 distal femora.
• Measurement of the angle between Whiteside's line and the epicondylar axis.
• Statistical analysis of the measured angles to assess reliability and variation.

Main Results:

• Whiteside's line was found to be perpendicular to the epicondylar axis in most specimens (mean 91 degrees).
• Significant variation was observed, with angles ranging from 80 to 102 degrees.
• The standard deviation of 4.7 degrees indicates considerable variability in the measurements.

Conclusions:

• Whiteside's line exhibits variability and should not be used as the sole reference for rotational alignment in total knee arthroplasty.
• Multiple rotational assessment axes are recommended to minimize errors in femoral prosthesis positioning.
• Ensuring accurate rotational alignment is critical for patellar tracking, joint forces, and overall surgical success.