A Novel Fluoroscopic Method for Assessing Rotational Malalignment of the Tibia.

Area of Science:

• Orthopedics
• Medical Imaging
• Biomechanical Engineering

Background:

• Tibial rotation is crucial for lower limb biomechanics.
• Accurate assessment of tibial rotation is essential for surgical correction of malrotation.
• Existing fluoroscopic methods for tibial rotation assessment have limitations.

Purpose of the Study:

• To evaluate the accuracy and reliability of a novel "intermalleolar" fluoroscopic technique for assessing tibial rotation.
• To compare the novel "intermalleolar" method with a previously described "mortise" fluoroscopic method.

Main Methods:

• A multiplanar circular ring external fixator was applied to cadaveric tibias.
• Tibias were randomly rotated internally and externally (5-30 degrees).
• Two blinded observers measured tibial rotation using "intermalleolar" and "mortise" fluoroscopic methods.

Main Results:

• Both methods showed a mean absolute rotational difference of 3 degrees from true torsion.
• The "intermalleolar" method achieved 98.5% accuracy within 10 degrees of true rotation, compared to 93.8% for the "mortise" method.
• Both methods demonstrated excellent interobserver reliability (ICC 0.99 for "intermalleolar", 0.96 for "mortise").

Conclusions:

• The "intermalleolar" fluoroscopic method is accurate and reliable for measuring tibial rotation.
• This novel method offers comparable accuracy to the "mortise" method.
• The "intermalleolar" technique is suitable for intraoperative identification and correction of tibial malrotation.