Digital Infrared Thermography Case of the Month: Juvenile Hip-Dysplasia-Canine

This month’s digital thermal imaging case involves imaging of a juvenile canine patient with hip dysplasia.

This case was provided by Trisha Allie, a registered veterinary technician of Grey Bruce Pet Hospital of Owen Sound Ontario.

An 11-month-old Rottweiler was presented for evaluation after a history of rear limb lameness.
A previous radiograph demonstrated significant abnormalities of the coxofemoral joints with flattening and remodeling of the femoral heads bilaterally. The lesions were more pronounced on the right side with subluxation present.

Physical Exam

A physical exam confirmed pain and a decreased range of motion in the coxofemoral joints and off loading on the right side.

Physiological Screen

A physiological screen was performed and three images were captured with a Digatherm IR 640 unit. Before the exam, the patient was acclimated to room temperature. The patient was not handled during the acclimation and remained calm during the image capture.

A similar frame was captured for both lateral images and the temperatures assigned to the palettes were both between 22 and 30.9 degrees centigrade (°C).

A dorsal view of the patient was imaged perpendicular to the lumbosacral area and the same temperatures of 22 to 30.9°C were assigned to the palette.

Analysis demonstrated a marked thermal asymmetry between the lateral images of the rear limbs.

The right hind lateral image showed hyperthermia from the hip extending distally and becoming more pronounced over the lateral aspect of the tibia. The average temperature in Zone 1R, over the right hip, was 29.5°C.

The left hind lateral image showed hypothermia radiating cranioventrally from the sacral area. The average temperature in Zone 1L, over the left hip, was 26.4°C.

Analysis of Zone 1 in both hind limbs showed an average temperature difference of 3.1°C or Delta T (ΔT)of 3.1°C. This marked difference in temperature represents a physiological hyperthermia on the right side and a physiological hypothermia on the left.

A dorsal thermal image of the lumbar and sacral area showed patchy, asymmetrical hypothermia over the right lumbosacral junction and throughout the left caudolateral sacral area.

The interpretation of these thermal images is consistent with radiographic evidence of juvenile hip dysplasia and the symptoms of rear limb lameness. They support the physical exam findings of pain and decreased range of motion in the coxofemoral joints and off loading on the right side.

Areas of hyperthermia are noted throughout the thermal image of the right rear leg which shows the most severe coxofemoral joint changes radiographically.

The areas of hypothermia noted on the left lateral and dorsal images were consistent with pain activation of the sympathetic nervous system, which can lead to peripheral vasoconstriction.

What did Digital Thermal Imaging Provide to this case?

It provided physiological evidence to accompany the history, radiograph, and physical examination findings.

This evidence provided the client with visualization of the extent that this disorder was affecting her pet. Visualization like this provides a better understanding of the status of the patient so treatment plan and care decisions can be made with greater compliance .

The thermal images provided evidence of physiological compensatory involvement throughout the lumbosacral area, and a roadmap for recommended medical or physical therapy.

It also provided a baseline set of images and temperature analysis for monitoring response to therapy with subsequent thermal images.