Radiographic measurements of Miniature Horse and Miniature Pony Feet.

Overview

• This study evaluated the reliability and precision of radiographic measurements used to assess foot conformation in Miniature Horses and Ponies, identifying hoof wall thickness ratios as consistent and clinically applicable metrics.

Introduction and Purpose

• Accurate assessment of foot conformation is key for managing foot health and conditions like laminitis in Miniature Horses and Ponies.
• Despite their importance, the reliability, precision, and reference ranges of radiographic foot measurements in these small equids are not well established.
• The study aimed to quantify several radiographic measurements, evaluate their agreement, reliability, and precision, and to provide reference ranges for clinical use.

Methods

• Subjects: 30 sound, skeletally mature Miniature Horses and Ponies.
• Radiographic imaging: Standardized lateromedial and dorsopalmar/plantarodorsal views of the feet were collected to capture accurate anatomical measures.
• Measurement procedure:
  • Two observers independently obtained 60 different measurements from 10 sets of radiographs, each on three separate occasions to test repeatability.
  • Reliability (consistency across observers and time) and precision (measurement variation within the same subject) were quantified.
  • Intraclass correlation coefficients (ICC) were used to assess reliability.
  • Within-subject coefficient of variation (CV) was calculated for precision.
  • Agreement was assessed through ±5% limits of agreement (LOA), indicating acceptable measurement difference ranges.
  • A single observer then measured the same parameters on 30 horses to establish median values and 95% confidence intervals.

Results

• Most linear and angular radiographic measures:
  • Showed moderate to excellent reliability (median ICC = 0.86).
  • Provided good precision (median CV = 4%).
  • However, many exceeded the ±5% limit of agreement, implying some inconsistency in clinical agreement thresholds.
• Hoof wall thickness ratios stood out:
  • Demonstrated good reliability with minimum ICC of 0.69.
  • Exhibited excellent precision, with maximum CV around 9%.
  • Had acceptable agreement within ±4.7% limits, making them suitable for clinical monitoring.
• Reference values for hoof wall thickness ratios (with 95% confidence intervals) were established:
  • Dorsal hoof wall thickness ratio: forefeet median 0.245, hindfeet median 0.240.
  • Lateral hoof wall thickness ratio: forefeet median 0.186, hindfeet median 0.180.
  • Medial hoof wall thickness ratio decreased slightly post-trim (pre-trim 0.177 to post-trim 0.169), indicating trimming effect.

Conclusions and Clinical Implications

• Hoof wall thickness ratios obtained via radiographs provide a consistent and reproducible measurement for Miniature Horses and Ponies.
• These measures can be reliably used in clinical practice to objectively screen, monitor, and manage foot health and laminitis in these animals.
• The study offers important reference ranges supporting evidence-based podiatric management in this population.
• While other angular and linear measurements may show variability beyond clinical acceptance limits, the hoof wall ratios are robust and suitable for repeated clinical use.