Septic arthritis in 15 standardbred racehorses after intra-articular injection.

The research is a case study on 15 adult Standardbred horses that developed septic arthritis after intra-articular injection. The study details the clinical background, synovial fluid analysis results, treatment methods, and outcomes for these horses. The main findings suggest that post-injection septic arthritis can negatively affect a racehorse’s performance, and effective treatment is dependent on prompt intervention and antibiotic therapy targeting penicillin-resistant staphylococci.

Analysis of Case Histories and Synovial Fluid

• The researched horses suffered from joint sepsis after intra-articular injection with corticosteroids, hyaluronic acid, polysulphated glycosaminoglycan, or local anesthetic.
• The median time from the injection to the onset of clinical signs was 2.5 days, and the median time to referral was nine days, indicating a rapid progression of the condition.
• Analysis of synovial fluid showed a median initial synovial leucocyte (white blood cell) count of 57 x 10(9)/litre, a sign of inflammation present in the affected joints.

Treatment Options and Responses

• All horses except one were lavaged, a cleaning process for infected joints.
• The process was either achieved non-surgically (three horses) or surgically through arthrotomy (one horse) or arthroscopy (seven horses).
• All the treated horses were initially given broad-spectrum parenteral antibiotic therapy since all the bacterial isolates identified were Gram-positive cocci, with majority (86%) being staphylococci.

Outcome and Recommendations

• Out of the 12 treated horses, 11 returned to racing. However, only three were rated as ‘satisfactory’ in their post-treatment performance, meaning they either improved or maintained their previous levels.
• The other nine horses were classified as ‘unsatisfactory’ due to diminished performance or inability to return to racing.
• The three horses that had a satisfactory outcome had been treated with arthroscopy and post-surgical closed suction drainage.
• Based on the bacterial cultures, the research suggests initiating treatment using antimicrobial agents effective against penicillin-resistant staphylococci due to the high prevalence of this bacterium in the cases studied.