Clinical measures of static foot posture do not agree

Area of Science:

• Biomechanics
• Podiatry
• Orthopedics

Background:

• Clinical assessment of foot structure relies on various classification measures.
• Understanding the agreement between these measures is crucial for accurate diagnosis and treatment.

Purpose of the Study:

• To evaluate the inter-rater and intra-rater reliability of common clinical foot classification measures.
• To determine the level of agreement between different foot assessment tools.

Main Methods:

• Static foot posture was assessed using the Foot Posture Index (FPI-6), rearfoot angle (RFA), medial longitudinal arch angle (MLAA), and navicular drop (ND).
• Measurements were taken on two separate occasions by the same rater on 30 participants.
• Agreement was analyzed using Weighted Kappa for within-measure comparisons and Fleiss Kappa for between-measure comparisons.

Main Results:

• Almost perfect agreement was found for MLAA (Kw=.92) and FPI-6 (Kw=.92) within measures.
• Moderate agreement was observed for RFA (Kw=.60), and fair agreement for ND (Kw=.40).
• Overall agreement between the different foot classification measures was moderate (Kf=.58).

Conclusions:

• Discrepancies exist among common clinical foot classification measures.
• The FPI-6 demonstrated good reliability, while navicular drop showed poor reliability and is not recommended.
• A consensus on standardized clinical measures for foot structure assessment is needed.