Smartphone-Based Pelvic Movement Asymmetry Measures for Clinical Decision Making in Equine Lameness Assessment.
Authors: Marunova, Dod, Witte, Pfau
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary Detecting hindlimb lameness through visual assessment alone remains inherently subjective, prompting clinicians to increasingly adopt objective measurement tools to complement their clinical judgement. Researchers fitted 301 horses with a smartphone secured to the sacrum to quantify pelvic movement asymmetry during trot, measuring three distinct parameters: vertical displacement minima, maxima, and upward movement amplitude differences, then correlating these against a single veterinarian's lameness grades (0–10 scale). Pelvic upward movement amplitude asymmetry (AbPDUp) emerged as the strongest discriminator between non-lame and lame horses (grades 1–4), with an area under the receiver operating curve of 0.801–0.852; applying a cut-off threshold of ≥7.5 mm achieved 75% sensitivity and 67.6% specificity, whilst the vertical displacement measures showed substantially lower diagnostic utility. For practitioners seeking an accessible, objective aid to lameness evaluation, this smartphone-based approach offers a practical in-field method requiring minimal equipment, though the moderate specificity of even the best-performing parameter suggests it functions most effectively as an adjunct to rather than a replacement for experienced clinical assessment. The findings warrant validation across multiple examiners and broader populations to establish whether these cut-off values are robust enough for standardised clinical adoption.
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Practical Takeaways
- •Pelvic upward movement amplitude asymmetry measured via smartphone can help objectively detect lameness as an adjunct to visual assessment, with a practical threshold of ≥7.5 mm identifying lame horses with reasonable sensitivity
- •This portable, low-cost technology could enable on-site objective lameness grading during clinical examinations to improve diagnostic consistency and support treatment decision-making
- •The highest diagnostic accuracy with AbPDUp suggests focusing measurements on vertical movement asymmetry rather than minimum or maximum pelvis heights when using smartphone accelerometry for lameness screening
Key Findings
- •Pelvic upward movement amplitude difference (AbPDUp) showed the highest discriminative power (AUC = 0.801-0.852) for detecting lameness using smartphone-based measurement
- •A cut-off point of AbPDUp ≥7.5 mm achieved 75% sensitivity and 67.6% specificity for distinguishing non-lame from lame horses (grades 1-4)
- •All three pelvic asymmetry measures (AbPDMin, AbPDMax, AbPDUp) showed significant differences across lameness grades (p < 0.001)
- •Smartphone-based sacral accelerometry provides objective, portable alternative to traditional lameness assessment methods