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Equine veterinary journal2025; doi: 10.1111/evj.70073

Lateromedial and oblique radiographs detect most fetlock pathologies as effectively as a full series in horses.

Abstract: Radiographic protocols for the metacarpo-/tarsophalangeal joint during pre-purchase examinations (PPE) vary internationally, but their impact on pathology detection remains unclear. Optimising imaging protocols is essential to balance diagnostic accuracy with workflow efficiency and radiation exposure. Objective: To evaluate the effect of different radiographic view combinations on fetlock pathology detection and observer agreement in a PPE context; hypothesising that detection rates vary with view selection. Methods: Retrospective observational study. Methods: Two observers reviewed fetlock radiographic series using four view combinations: lateromedial (LM) alone, LM and dorsopalmar/plantar (LM/DP), LM and oblique projections (LM/OB), and the full series (FULL). McNemar's chi-squared test assessed detection differences; Cohen's kappa evaluated intra- and inter-observer agreement, and diagnostic parameters were calculated for reduced views relative to the full series. Results: A total of 673 fetlock series were reviewed. The LM/OB combination showed no significant difference in detecting most pathologies compared to the full series. Observer agreement was generally highest with the full series. Intra-observer agreement was highest for LM/OB, except for subchondral bone changes in the proximal phalanx, where LM/DP performed better; though overall agreement was low. Lateromedial projections reliably detected fragmentation, sesamoid fractures, and osseous cyst-like lesions. Oblique views were superior for sesamoid bone changes. Conclusions: Retrospective design, selection bias, and lack of gold standard confirmation. Conclusions: While LM/OB offers a practical compromise in many PPE scenarios, certain pathologies, particularly subchondral bone changes, may require additional views. A tailored approach based on age, discipline, and clinical risk may optimise diagnostic yield. Background: Les protocoles radiographiques pour l’articulation métacarpo‐/tarsophalangienne durant les examens vente et achat varient d’un pays à l’autre et leur impact sur la détection des pathologies demeure incertain. L’optimisation des protocoles d’imagerie reste essentielle afin de balancer l’acuité diagnostique avec l’exposition aux radiations et l’efficacité de travail. Objective: Évaluer l’effet de différentes combinaisons de projections radiographiques sur la détection des pathologies du boulet équin et le degré d’accord des observateurs dans un contexte d’examen vente et achat, avec l’hypothèse que les taux de détection varient selon la projection sélectionnée. TYPE D’ÉTUDE: Étude rétrospective observationnelle. MÉTHODES: Deux observateurs ont examiné des séries de radiographies du boulet en utilisant 4 combinaisons de projections: latéromédiale uniquement (LM), LM et dorsopalmaire/plantaire (LM/DP), LM et projections obliques (LM/OB) et séries complètes (FULL). Le test du khi carré de McNemar a été utilisé pour analyser les différences de détection, le Kappa de Cohen a évalué l’accord inter‐intra‐observateur et les paramètres diagnostics ont été calculés pour les combinaisons de projections comparativement aux séries complètes. RÉSULTATS: Un total de 673 séries radiographiques du boulet ont été examinées. La combinaison LM/OB n’a montré aucune différence dans la détection de la majorité des pathologies, comparativement aux séries complètes. L’accord des observateurs était généralement supérieur avec les séries complètes. L’accord intra‐observateur était plus élevé pour les LM/OB, à l’exception des changements de l’os sous‐chondral au niveau de la première phalange, où les LM/DP étaient plus diagnostiques, tous avec un accord somme toute bas. Les projections latéromédiales ont détecté les fragmentations, les fractures des os sésamoïdiens proximaux et les lésions osseuses de forme kystique. Unassigned: Nature rétrospective de l’étude, biais de sélection, manque de gold standard pour confirmation absolue. Conclusions: Alors que les LM/OB offre un compromis pratique pour plusieurs scénarios d’examen vente et achat, certaines pathologies, tel que les changements osseux sous‐chondraux, peuvent nécessiter davantage de projections radiographiques. Une approche adaptée à l’individu, basée sur l’âge, la discipline et les risques cliniques devrait optimiser le rendement diagnostic.
Publication Date: 2025-08-13 PubMed ID: 40803993DOI: 10.1111/evj.70073Google Scholar: Lookup
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  • Journal Article

Summary

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The research examines how different combinations of radiographic views affect the detection of fetlock (a joint in a horse’s leg) pathology and observer agreement during pre-purchase examinations (PPE) of horses. It suggests that using a combination of lateromedial (front to back) and oblique radiographs is almost as effective as using a full series of views for most types of pathology.

Methodology

  • The study is a retrospective observational one. This means that it used previously collected data to observe trends and make conclusions about relationships between different variables.
  • Two observers reviewed fetlock radiographic series from 673 examinations. They used four different combinations of views – lateromedial (LM) alone, LM and dorsopalmar/plantar (LM/DP, top and bottom views), LM and oblique projections (LM/OB), and the full series (LM, DP, and oblique views together).
  • The detection rates of various pathologies with these different view combinations were analyzed.
  • McNemar’s chi-squared test assessed the differences in detection, Cohen’s kappa evaluated the intra- and inter-observer agreement, and diagnostic parameters were calculated for reduced views relative to the full series.

Findings

  • The LM/OB combination showed no significant difference in detecting most pathologies compared to the full series.
  • Observer agreement was generally highest with the full series. Intra-observer agreement was highest for LM/OB, except for subchondral bone changes in the proximal phalanx, where LM/DP performed better.
  • Lateromedial projections reliably detected fragmentation, sesamoid fractures, and osseous cyst-like lesions. Oblique views were superior for sesamoid bone changes.
  • The study’s retrospectivity, selection bias, and lack of a gold standard for absolute confirmation were identified as limitations.

Conclusions

  • The combination of lateromedial and oblique radiographs offers a practical compromise in many pre-purchase examination scenarios. This means that most of the necessary information can be obtained with fewer views, saving time and reducing radiation exposure.
  • Certain pathologies, particularly changes in subchondral bone, may still require additional views for accurate detection. This indicates that a tailored approach based on factors such as the horse’s age, discipline, and clinical risk may optimize the diagnostic yield.

Cite This Article

APA
Northwood A, Berner D. (2025). Lateromedial and oblique radiographs detect most fetlock pathologies as effectively as a full series in horses. Equine Vet J. https://doi.org/10.1111/evj.70073

Publication

ISSN: 2042-3306
NlmUniqueID: 0173320
Country: United States
Language: English

Researcher Affiliations

Northwood, A
  • The Royal Veterinary College, Equine Referral Hospital, Hertfordshire, UK.
Berner, D
  • The Royal Veterinary College, Equine Referral Hospital, Hertfordshire, UK.

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