Clinical and Diagnostic Imaging Findings in Police Working Dogs Referred for Hip Osteoarthritis

Published: Alves et al. BMC Veterinary Research (2020) 16:425.

Keyword: Dog, Osteoarthritis, Hip, Stance Analysis, Digital Thermography Goniometry, Digital radiography, Clinical Metrology Instruments

Author(s): J. C. Alves, A. Santos, P. Jorge, C. Lavrador and L. Miguel Carreira

Overview:  Osteoarthritis (OA) is the most commonly diagnosed joint disease in veterinary medicine, with at least 80% of the cases of lameness and joint diseases in companion animals being classified as OA. Sporting and working animals are more predisposed to develop OA since they are exposed to chronic fatigue injuries, leading to bone and muscular tissue damage and failure, resulting in clinical signs. To characterize the clinical signs and diagnostic findings of Police working dogs presenting with bilateral hip OA at the time of diagnosis.

Weight distribution and off-loading or limb favoring at stance is a commonly used subjective assessment during orthopedic examination [16]. Animals with OA may not be overtly lame at a walk or a trot but exhibit subtle shifts in body weight distribution at a stance due to pain or instability [17, 18]. Stance analysis has been reported as sensitive for detecting lameness in dogs, with better results in large breed dogs.

Materials/Methods:

• Fifty animals were evaluated with a bodyweight ≥ 15 kg, be older than two years, and without any medication or nutritional supplements for ≥ 6 weeks.
• The sample included 30 males and 20 females, with a mean age of 6.5 ± 2.4 years and a bodyweight of 26.7 ± 5.2 kg.
• Weight distribution, joint range of motion at flexion and extension, thigh girth, digital thermography, and radiographic signs were collected.
• Data from different Clinical Metrology Instruments (CMI) were collected: Canine Brief Pain Inventory, Liverpool Osteoarthritis in Dogs, Canine Orthopedic Index, and the Hudson Visual Analogue Scale.
• Results were compared by breed, age, sex, and Orthopedic Foundation for Animals hip grades

Results: 

• Animals with weight distribution below normal levels had significant variations of joint extension and function scores.
• This evaluation was the only not correlated with at least one breed.
• Animals with caudolateral curvilinear osteophyte showed a poorer clinical presentation and worse scores in all considered CMIs.
• Radiographic changes correlated with age and corresponded to worse CMIs scores and weight distribution.
• Dutch Shepherd Dogs showed better CMI scores than the other considered breeds.
• For the evolution of hip OA, bodyweight distribution at a stance may even be a superior measurement to Vertical Instability and Peak Vertical Force since dogs present different standing postures to increase acetabular coverage.

Conclusions: Police working dogs presented with complaints related to hip OA at an early stage of the disease. Hip scores influenced clinical presentation, with moderate cases showing lower thigh girth and worse pain interference and severity, and function scores than mild cases. Patients with severe OA had lower thermographic evaluations than patients with moderate OA. Age was the primary variable influencing considered CMI scores.