Effects of intra-articular injection of an acellular equine liquid amniotic allograft in healthy equine joints.
Authors: Wolkowski Danica D, McCarthy Robert D, Schoonover Mike J, Taylor Jared D, Eastman Timothy G
Journal: Veterinary surgery : VS
Summary
# Editorial Summary Acellular equine liquid amniotic allograft (ELAA) is increasingly considered for intra-articular use in equine orthopaedics, but rigorous safety and biological data in healthy joints remain limited. This randomised, blinded, controlled study injected eight healthy horses with either 1.5 ml ELAA or saline into one intercarpal joint, with the contralateral joint serving as control, then assessed lameness (subjectively and via force plate), alongside synovial fluid markers including interleukin-1 receptor antagonist (IL-1ra) over 30 days. The treatment group showed significantly elevated total nucleated cell counts (TNCC) on days 1 and 3 (6039 and 1119 cells/µl respectively, versus 240 cells/µl in controls), coupled with heightened IL-1ra concentrations at the same timepoints (3553.7 and 2283.2 pg/ml versus 1890.1 and 1250.7 pg/ml), yet no lameness developed and force plate analysis revealed no functional impairment in either limb throughout the study period. Whilst the transient cellular and inflammatory response warrants monitoring, the absence of clinical lameness or measurable gait abnormalities suggests ELAA poses no acute safety risk to structurally sound joints—findings that provide preliminary support for its use in naturally inflamed joints where the elevated IL-1ra response might confer protective, anti-inflammatory benefits. Further investigation in experimentally induced joint pathology would clarify whether this endogenous cytokine upregulation translates to meaningful clinical advantage in therapeutic applications.
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Practical Takeaways
- •ELAA injection appears safe for use in equine joints with no adverse effects on soundness or gait in healthy horses
- •The drug triggers an anti-inflammatory response (elevated IL-1ra) that may be therapeutically useful in inflamed or damaged joints, though efficacy in clinical lameness requires further study
- •Consider ELAA as a potential future treatment option for joint inflammation, but current evidence is limited to healthy joints—clinical validation in diseased joints is needed before routine practice adoption
Key Findings
- •ELAA injection caused significantly elevated total nucleated cell count (TNCC) in synovial fluid on days 1 and 3 (6039 and 1119 cells/μl vs 240 cells/μl control, P<0.001)
- •IL-1ra concentration was significantly higher in treated joints on days 1 and 3 (3553.7 and 2283.2 pg/ml vs 1890.1 and 1250.7 pg/ml control, P≤0.01)
- •No lameness was detected in any treatment group on any study day (P=0.75), and no changes in force plate metrics occurred
- •No safety concerns were observed with ELAA injection into healthy joints over the 30-day study period