Infrared thermal imaging as a non-invasive pre- diagnostic tool for knee osteoarthritis: A cross-sectional study

Abstract

Knee osteoarthritis is a degenerative joint disease, causing pain and reduced mobility, especially in older adults. Current imaging methods like CT, MRI, and bone scintigraphy mainly reveal structural changes, but have limitations such as radiation exposure, high cost, and limited repeatability. In contrast, infrared thermal imaging is a non-invasive, radiation-free technique that detects temperature changes linked to joint inflammation. It offers real-time, repeatable results, making it useful for monitoring and guiding timely interventions. This cross-sectional study was conducted on 56 participants diagnosed with knee osteoarthritis to evaluate the role of infrared thermal imaging in assessment and immediate monitoring. Thermal imaging measurements were obtained from both affected and contralateral knees using standardized protocols. Clinical assessment included Kellgren-Lawrence grading, Western Ontario and McMaster Universities Osteoarthritis Index, and Visual Analogue Scale pain scores. Statistical analysis included receiver operating characteristic curve analysis, correlation analysis, and diagnostic performance metrics. Result showed that the mean temperature difference between affected and contralateral knees was 1.80 ± 0.64 °C (p < 0.001, Cohen's d = 2.81). Thermal temperature differences showed significant correlation with Kellgren-Lawrence grade severity (r = 0.442, p < 0.001). Using an optimal cutoff of 1.16 °C, thermal imaging demonstrated 95 % sensitivity and 43 % specificity for detecting clinically significant osteoarthritis. The area under the receiver operating characteristic curve was 0.65. This research concluded that Infrared thermal imaging provides a non-invasive method for detecting knee osteoarthritis with high sensitivity. The technique shows promise as an adjunctive diagnostic tool, particularly for screening and monitoring disease progression.