Evaluation of Digital Thermography Imaging to Assess and Monitor Treatment of Police Working Dogs with Naturally Occurring Hip Osteoarthritis

Overview 

In dogs, thermal imaging has been documented only recently, but a growing interest in this modality has led to studies using thermography to assess pathologies in the canine hip, stifle, elbow, intervertebral disc, and bone neoplasia. This study aimed to evaluate the use of digital thermography in assessing and evaluating treatment response in dogs with hip osteoarthritis (OA) and comparing its results with an objective measure (the Companion Stance Analyzer™) and two clinical metrology instruments.

Materials/Methods 

• In an experimental, randomized, double-blinded study, one hundred hip joints of fifty police working dogs with bilateral hip OA were evaluated.
• A dorsoventral and lateral thermographic image were obtained on days 0, 8, 15, 30, 90, and 180. Mean and maximal temperatures were determined.
• Additionally, the animal’s weight-bearing distribution and radiographic examination of the hip joint (extended legs ventrodorsal view) were performed.
• Copies of the Canine Brief Pain Inventory (CBPI) and Canine Orthopaedic Index (COI) were obtained. • The Stance Analyzer™ was utilized in this study to evaluate individual limb weight-bearing, an objective measure, as it is sensitive for detecting lameness in dogs and an equivalent or superior measurement of hip OA-related pain compared to vertical impulse and peak vertical force. Results:
• Mean and Maximal Values recorded on the lateral thermographic view were higher than those on the dorsoventral view.
• No differences or correlations were found between Orthopedic Foundation for Animals hip grades and temperature.
• Digital thermographic images showed a weak significant correlation with weight-bearing evaluations (r = 0.13, p < 0.01) and different clinical metrology instruments scores (r = − 0.25, p < 0.01 for pain severity score, and r = − 0.21, p = 0.04 for gait).
• It also correlated with radiographic findings, specifically the circumferential femoral head osteophyte and caudolateral curvilinear osteophyte.

Conclusions 

To our knowledge, this is the first study presenting the digital thermography assessment of police working dogs submitted to treatment for hip OA. Digital thermography, mainly based on a lateral view evaluation, showed a weak significant correlation with stance analysis and clinical metrology instruments scores.