Severe acute inflammatory reaction (SAIR) of the fetlock joint after intraarticular hyaluronate injection in a horse.

This research article explores a case of severe acute inflammatory reaction in a horse’s joint (the fetlock) following an injection of hyaluronate. The injection was meant to treat osteoarthritis, but instead led to severe inflammation and required extensive treatment.

Background

• The study examines the unintended side effects that occurred when a particular treatment for metacarpophalangeal osteoarthritis, an intra-articular injection of hyaluronate, was administered to a 13-year-old Haflinger mare.
• Intra-articular injection of hyaluronate is usually administered to alleviate symptoms of osteoarthritis, a joint condition commonly seen in horses. However, in this particular case, the treatment triggered an intense inflammatory response in the horse.

Reactions and Treatments

• Within hours post-injection, the horse developed a severe inflammatory reaction in the treated joint. In response to the inflammation, the horse was treated for iatrogenic infectious arthritis, a condition often induced due to therapeutic procedures.
• However, the analysis of synovial fluid (fluid which reduces friction in articulating joints) did not confirm sepsis, a potentially life-threatening condition caused by the body’s response to an infection.
• Following the systemic administration of a non-steroidal anti-inflammatory medication, the horse’s clinical signs improved significantly and the horse was discharged three days later.

Post Treatment Reactions

• The horse was again treated with hyaluronate, administered intravenously this time, about four days after its discharge.
• Unfortunately, the joint inflammation reappeared. Analysis of the synovial fluid did not reveal any abnormalities, but the signs of inflammation were severe.

Conclusion

• Ultimately, in order to resolve the issue, systemic non-steroidal anti-inflammatory and intra-articular corticosteroid treatments were needed.
• This intense reaction to the hyaluronate treatment presents a challenge to treating osteoarthritis in horses and may necessitate more experimental trials or research to identify and understand potential side-effects.