Gabrielle Solum

and 7 more

Background: Pathologic changes of the fetlock joint are well documented in thoroughbreds but little information is available describing the common radiographic findings in western performance horses with fetlock lameness. Objectives: Describe radiographic findings in western performance horses with lameness localized to the fetlock. It was hypothesized degree of lameness would correlate with severity of radiographic findings. Study design: Retrospective case series Methods: A retrospective review (2012-2022) of horses with lameness isolated to the fetlock joint via intra-articular analgesia and corresponding fetlock radiographs were included. Signalment, lameness, flexion and effusion grades were recorded. Radiographs were evaluated for presence, severity, and location of pathology. Subjective radiographic severity scores were assigned. Correlations between outcome parameters were evaluated with Spearman’s correlation coefficient. Statistically significant changes in mean lameness grades for each radiographic abnormality were determined using Wilcoxon Rank Sum test. Results: Ninety cases met inclusion criteria. Radiographic lesions were identified in 96.7% of cases. Distal cannon bone sclerosis, periarticular osteophytes, increased soft tissue, proximal phalanx (P1) sclerosis, and subchondral bone (SCB) defects were most common. Horses with P1 sclerosis, SCB cysts, and P1 fissures had significantly higher lameness grades. No significant correlation was established between overall radiographic score and lameness grade . Main limitations: Outcome parameters were not captured for every horse due to retrospective design. Diagnostic analgesia has inherent limitations with specificity and interpretation of results. The use of multiple clinicians may have led to inconsistencies in grading of lameness, flexion response and improvement after diagnostic analgesia. Conclusions: Horses in this study demonstrated changes associated with chronic exercise-induced remodelling and degenerative joint disease. While degree of lameness did not correlate with overall radiographic score, certain radiographic findings- P1sclerosis SCB cysts, and P1 fissures- were correlated with higher degree of lameness.