Spontaneous Septic Arthritis of Canine Elbows: Twenty-One Cases.

Abstract

OBJECTIVE:  This study provides information on clinical features, diagnosis, treatment and associated risk factors of spontaneous septic elbow arthritis in the dog. METHODS: Medical records between March 2007 and June 2015 were searched for cases of spontaneous septic elbow arthritis with a diagnosis based on clinical signs, arthrocentesis, cytological and microbiological analysis of elbow joint synovial fluid, radiography and outcome following treatment. RESULTS: Twenty-one cases of septic arthritis were identified. Pre-existing osteoarthritis was present in 14/15 elbows for which diagnostic imaging was available. Although all cases had increased neutrophil count on synovial fluid cytology, culture was only positive in 12/21. Despite initial improvement in lameness scores (pre-treatment 9/10 [range: 1-10] versus post-treatment 3/10 [range: 1-5]), 11/12 had residual long-term lameness. Recurrence of infection was noted in 3/12 elbows for which long-term (>8 weeks) follow-up was available. There was an acute mortality rate of 2/21 associated with severe systemic sepsis. CLINICAL SIGNIFICANCE: Septic arthritis, even in the absence of pyrexia, should be considered as a major differential diagnosis in middle aged, large breed dogs, with pre-existing elbow arthritis, that suffer an acute onset lameness, with elbow joint effusion and discomfort. Antibiotic therapy alone was effective for treatment with high initial response rates. Chronic lameness post-treatment was common, and a high rate of recurrence was seen with 3/12 dogs suffering more than one episode.