Osteoarthritis of the coxofemoral joint in 24 horses: Evaluation of radiography, ultrasonography, intra-articular anaesthesia, treatment and outcome.
Authors: Sauer Fay J, Hellige Maren, Beineke Andreas, Geburek Florian
Journal: Equine veterinary journal
Summary
# Equine Coxofemoral Joint Osteoarthritis: Clinical Recognition and Diagnostic Framework Coxofemoral joint osteoarthritis (CFJOA) remains poorly documented in the equine literature, despite causing severe, intractable lameness in affected horses. This retrospective analysis of 24 cases (median age 14 years) presented between 2002 and 2023 provides the first standardised radiographic scoring system and comprehensive evaluation of diagnostic modalities, revealing that characteristic clinical signs—including unilateral gluteal atrophy (18/21 horses), lengthened stride (13/19) and three-track locomotion (13/20)—should prompt investigation. Both radiography and ultrasonography can identify periarticular osteophytes (r = 0.64), but ventrodorsal radiographs uniquely detect irregular joint spaces, subchondral bone changes and femoral head deformities; the authors' new radiographic score demonstrated excellent inter- and intra-observer reliability (Cohen's κ = 0.846–0.853), making standardised assessment feasible in clinical practice. Crucially, all surviving horses (15/24) remained permanently lame despite treatment, predominantly with intra-articular corticosteroids, and post-mortem examination frequently revealed rupture of the ligamentum capitis ossis femoris, suggesting underlying joint instability as a primary driver of poor prognosis and medical therapy resistance. These findings indicate that CFJOA warrants early recognition through clinical phenotyping and careful radiographic evaluation, though practitioners should counsel owners realistically about outcome, as current medical management offers limited functional improvement.
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Practical Takeaways
- •CFJOA should be suspected in older horses (median age 14 years) with chronic unilateral lameness, gluteal atrophy, and altered gait mechanics (three-track locomotion, stride lengthening)
- •Ventrodorsal radiographs are the gold standard for diagnosis and should be routinely obtained when CFJOA is suspected; the new standardised radiographic score facilitates consistent assessment and documentation
- •Medical management with intra-articular corticosteroids has poor long-term outcomes; postmortem evidence of ligamentous rupture suggests joint instability is a driving factor, explaining resistance to conservative therapy and potentially guiding future treatment strategies
Key Findings
- •20 of 24 horses (83%) presented with chronic lameness; clinical signs included unilateral gluteal atrophy (18/21), stride lengthening (13/19), and three-track locomotion (13/20)
- •Radiography and ultrasonography both detected periarticular osteophytes (r=0.64, p=0.003), with radiography additionally revealing irregular joint spaces, subchondral bone changes, and femoral head deformities
- •The radiographic scoring system demonstrated excellent inter-observer (κ=0.846) and intra-observer (κ=0.853, κ=0.842) agreement for standardised assessment
- •Postmortem findings revealed rupture of the Ligamentum capitis ossis femoris in most cases; all surviving horses remained lame despite medical treatment with intra-articular corticosteroids (16/18 treated)