Clinical Communication Arthrotomy for the treatment of chronic purulent septic gonitis with subchondral osteolysis in two calves M Heppelmann* x , C Staszyk { , J Rehage* and A Starke* Abstract CASE HISTORY: A 6-week-old German Holstein heifer calf (Case 1) and a 4-week-old Charolais bull calf (Case 2) were referred because of unilateral hind limb lameness. Both had been treated with systemic antibiotics by the referring veterinarian. CLINICAL FINDINGS AND DIAGNOSIS: Based on the results of clinical, radiographic and ultrasonographic examina- tion, a diagnosis of chronic purulent septic gonitis with subchondral osteolysis of the lateral femoral condyle was made in both calves. In Case 2 the lateral tibial condyle also showed osteolysis. TREATMENT AND OUTCOME: Treatment consisted of arthrotomy with debridement of abnormal bone and cartilage via a craniolateral and a caudolateral approach. Case 1 was discharged from with grade 1/5 lameness 60 days after surgery. In a follow-up 15 months postoperatively, the owner reported that it had been bred at 14 months, was not lame and the affected stifle joint appeared normal. Case 2 had grade 2/5 lameness 52 days after surgery, but was sound at the time of slaughter at 22 months of age. CLINICAL RELEVANCE: Arthrotomy via a caudolateral approach is a suitable method for the treatment of septic purulent gonitis with osteolysis of the lateral femoral and tibial condyles in calves. In these cases, this treatment resulted in the elimination of localised inflammation, prevented clinically relevant spread of infection to other organs, and restored normal joint function. KEY WORDS: Cattle, stifle joint, osteolysis, surgery, ultrasono- graphy, radiography Introduction Septic gonitis is a common form of arthritis in calves, and osteolytic changes in the joint are a frequent complication (Madison et al. 1989; Butson et al. 1996; Ducharme 1996). Osteolysis has been reported to occur in the lateral condyles of the femur and tibia in association with inflammation of the lateral femorotibial joint (Nuss 2000). Surgical treatment is indicated in those cases as well as in cattle with chronic arthritis with thick intraarticular pus or fibrin deposits, or when conservative treatment fails (Verschooten et al. 1974; Van Huffel 1996; Starke et al. 2009). Arthroscopy is of limited use because fibrin may impair visibility and orientation within the joint, and debridement of large and deep osteolytic lesions is difficult (Madison et al. 1989). In contrast, arthrotomy allows far better access to all areas of the joint and removal of exudate and abnor- mal tissue (Starke et al. 2009). However, treatment is generally considered difficult because of the complicated structure of the stifle joint with its multiple compartments. Furthermore, the surgical approaches to the different compartments are not straight- forward because of their close association with muscles, blood vessels and nerves. To date, arthrotomy in cattle has been limited to the cranial part of the stifle joint, i.e. the femoropatellar joint compartment and cranial part of the lateral and medial compart- ments of the femorotibial joint (Verschooten et al. 1974; Van Huffel 1996). Arthrotomy via a simple cranial approach is usually inadequate because the relatively large caudal part of the lateral compartment of the femorotibial joint and the caudal part of the condyles are not entirely accessible (Verschooten et al. 1974). This paper describes the treatment and outcome of two calves with chronic purulent septic gonitis with subchondral osteolysis. Arthrotomy via a cranial and caudal approach was used in both cases. Case history Case 1 was a 6-week-old German Holstein heifer calf, weighing 50 kg that presented with left hind limb lameness, swelling of stifle joint of 5 weeks duration and been treated with systemic antibiotics by the referring veterinarian. Case 2 was a 4-week-old Charolais bull calf, weighing 65 kg that was presented with purulent arthritis of the right stifle that had been present since birth. It had been treated with systemic antibiotics. Clinical findings The clinical findings for both calves are summarised in Table 1. In Case 1, a circular radiolucent area on the lateral condyle of the femur was seen on craniocaudal and lateromedial radiograpic views (Figure 1), and examination using ultrasonography showed an area of massive bone loss with an irregular surface in the lateral * Clinic for Cattle, University of Veterinary Medicine Hannover, Foundation, Bischofsholer Damm 15, 30173 Hannover, Germany. { Institute of Anatomy, University of Veterinary Medicine Hannover, Foundation, Bischofsholer Damm 15, 30173 Hannover, Germany. x Author for correspondence. Email: maike.heppelmann@tiho-hannover.de New Zealand Veterinary Journal 60(5), 310–314, 2012 310