Effects of Carbon Dioxide Infrared Laser Moxibustion on Pain and Function in Knee Osteoarthritis

Knee osteoarthritis is a prevalent degenerative joint disorder characterized by chronic knee pain, stiffness, reduced range of motion, and limitations in daily functional activities. Exercise therapy is widely recommended as a first-line conservative approach to reduce symptoms and improve physical performance; however, a substantial proportion of patients continue to experience persistent pain and functional impairment despite adherence to exercise-based rehabilitation. Carbon dioxide (CO2) infrared laser moxibustion is a non-invasive far-infrared thermal stimulation modality intended to reproduce the localized heating effects of traditional moxibustion without smoke or odor. It is hypothesized to enhance local microcirculation, support tissue oxygenation, and modulate inflammatory activity, thereby contributing to symptom relief and improved joint function. This double-blind, parallel-group randomized controlled trial will evaluate whether adding carbon dioxide (CO2) infrared laser moxibustion to a standardized knee osteoarthritis exercise program provides greater improvement than exercise alone. Eligible participants with radiographic knee osteoarthritis will be randomly allocated to either (1) an exercise-only program or (2) the same exercise program plus carbon dioxide (CO2) infrared laser moxibustion delivered over an 8-week treatment phase (24 sessions). Outcomes will be measured at baseline and at follow-up visits at Month 3 and Month 6 to determine changes in pain intensity measured by the Numerical Pain Rating Scale (NPRS), knee range of motion measured by goniometry, articular cartilage thickness measured by magnetic resonance imaging (MRI), and biochemical markers including bone alkaline phosphatase (BAP) and serum calcium.