A medial malleolus marker provides precise measurements of tibial torsion that align closely with EOS.

BACKGROUND

Tibial malalignment often occurs in children with neurological and musculoskeletal disorders like cerebral palsy. Tibial torsion measurement, crucial for treatment decisions, is typically assessed using the conventional gait model, which places markers on the lateral shank, knee, and malleolus. However, accurately placing these markers can be challenging. Studies suggest adding a medial malleolus marker improves measurement accuracy. Additionally, EOS imaging provides a low-radiation, cost-effective method for measuring tibial rotation. This study aimed to evaluate the accuracy of the conventional gait model versus the medial malleoli marker method, compare these with passive goniometer measurements, and correlate results with EOS imaging.

METHODS

In a cohort of 31 participants (aged 5-17 years), tibial torsion was assessed through physical exams, gait analysis, and EOS imaging. Tibial rotation was analyzed using the conventional model and medial malleoli marker method. Correlations between methods were assessed using Pearson's coefficient and Bland-Altman plots.

FINDINGS

The medial malleoli marker method correlated more strongly with EOS imaging (r = 0.66) than the conventional model (r = 0.27). It also showed excellent agreement with passive goniometer measurements (r = 0.92). EOS imaging consistently reported higher torsion values compared to other methods.

INTERPRETATION

Adding a medial malleolus marker enhances the accuracy and reliability of tibial rotation measurements compared to the conventional gait model. While discrepancies exist with EOS imaging, the medial malleoli marker method shows stronger alignment with both passive and imaging-based assessments.