Partial rupture of the biceps tendon with concurrent septic arthritis of the shoulder joint in a dog

A 7-year-old, male-neutered, Cockapoo presented for rapidly deteriorating non-weight bearing (5/5) left thoracic lameness with poorly localised severe pain. Based on physical examination, advanced diagnostic imaging and cytology of joint fluid, a diagnosis was made of left partial biceps tendon rupture with presumptive secondary bacterial infectious arthritis of the left shoulder. No obvious source of bacteraemia was found. Initial treatment with intravenous antibiotics and multimodal analgesia for 48 h led to rapid improvement of the clinical signs. Following seven weeks of oral antibiotic therapy, at clinical reassessment, the clinical signs had steadily improved with persistent mild left forelimb lameness (1/5). Ultrasound examination revealed signs of left biceps tendon healing. Fifteen weeks after initial presentation, the patient had no lameness or pain and had returned to normal exercise levels as reported by the owner.