The accuracy of infrared thermal imaging and ultrasound in evaluating knee osteoarthritis dysfunction

To explore the accuracy of infrared thermal imaging and ultrasound in evaluating knee osteoarthritis (KOA) dysfunction.

From November 2021 to June 2022, 50 KOA patients diagnosed by our hospital were selected. According to the results of ultrasound examination, the subjects were separated into mild group (30 cases) as well as moderate to severe group (20 cases). Pain as well as dysfunction was assessed using the visual analog Scale (VAS) and Western Ontario and McMaster osteoarthritis index (WOMAC). The forward-looking infrared (FLIR) thermal imager was used for infrared thermal imaging on the day of treatment as well as 1 month later.

The degree of cartilage wear detected by ultrasound was strongly correlated with the pain of knee osteoarthritis (r=0.674, P<0.05) and WOMAC osteoarthritis index (r=0.643, P <0.05). The knee temperature in the moderate to severe group was higher relative to the mild group (P<0.05, figure 2). The reliability and repeatability of the two infrared thermal imaging tests in knee were good (ICC=0.78). The knee temperature was positively correlated with the degree of cartilage wear under ultrasound (r=0.426, P<0.05, table 2). The knee temperature was positively related to pain (r=0.403, P<0.05) and WOMAC osteoarthritis index (r=0.382, P<0.05).

Combined application of infrared thermal imaging and ultrasound in the evaluation process of knee osteoarthritis can assess the pain and dysfunction of knee osteoarthritis to a certain extent.