Clinical Scenario: Knee osteoarthritis (KOA) is typically more experienced in older populations and conservative treatment strategies favor ultrasound as a treatment option. In the past thermal diathermy was used more frequently as a treatment method before ultrasound was more widely administered. However, there is no conclusive evidence stating which treatment method is more beneficial. Focused Clinical Question: Is diathermy as effective or more effective as ultrasound in reducing symptoms in patients suffering with KOA? Summary of Key Findings: All three studies showed no significant difference in WOMAC scores between subjects who received diathermy compared to those who received ultrasound. One study demonstrated a reduction in KOA symptoms as measured by WOMAC scores for both groups between 12 weeks of treatment and 24 weeks of treatment. All three studies demonstrated a decrease in pain rating and an increase in patient performance for activities of daily living from pre and post scores. Clinical Bottom Line: The evidence from the articles state that diathermy is equally effective as ultrasound when treating patients with symptoms of KOA. Strength of Recommendation: Grade B evidence as one of the articles is a comparative study instead of a randomized control trial. However, with no statistical difference being reported in any articles it indicates that diathermy has similar results as ultrasound for treating patients with KOA. Key Words: Knee osteoarthritis, diathermy, shortwave diathermy, radio frequency diathermy, ultrasound, pulsed ultrasound, WOMAC score, VAS score