Evaluation of limb load asymmetry using two new mathematical models

Area of Science:

• Biomechanics
• Rehabilitation Engineering
• Orthopedics

Background:

• Accurate limb loading measurement is crucial for orthopedic and neurological rehabilitation.
• Existing models like Symmetry Index (SI), Symmetry Ratio (SR), and Symmetry Angle (SA) have identified limitations in quantifying limb loading asymmetry.
• There is a need for more precise and interpretable mathematical models for limb loading analysis.

Purpose of the Study:

• To introduce and evaluate two novel mathematical models: Modified Symmetry Index (MSI) and Limb Loading Error (LLE).
• To address the limitations of current mathematical models used for quantifying limb loading asymmetry.
• To compare the performance of new models against existing ones for improved limb loading pattern interpretation.

Main Methods:

• Development of two new mathematical models: MSI and LLE.
• Simulation of hypothetical data covering all numerical possibilities of even and uneven limb loading.
• Algorithmic preliminary computational measure using descriptive statistics to interpret limb loading patterns (symmetry, asymmetry, maximum asymmetry).
• Comparative analysis of five mathematical models (SI, SR, SA, MSI, LLE).

Main Results:

• All five models demonstrated similarity in analyzing limb symmetry.
• SA and SR provided no meaningful interpretation for asymmetry and maximum asymmetry data.
• SI yielded inflated values for asymmetry and maximum asymmetry.
• MSI and LLE offered direct, easily interpretable results, identifying loading patterns and the side of asymmetry.
• The new models successfully quantified the amount and side of asymmetry across different loading patterns.

Conclusions:

• MSI and LLE are superior to SI, SR, and SA for quantifying limb loading asymmetry.
• The new models provide direct, interpretable insights into the amount and laterality of asymmetry.
• MSI and LLE represent a significant advancement in assessing limb loading patterns in rehabilitation contexts.