Western Performance Horses with fetlock lameness demonstrate
radiographic evidence of chronic exercise remodelling
Abstract
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.