Materials and Methods: 55 women aged 56.03±5.7 years who had mild or moderate knee osteoarthritis were randomly allocated into 3 groups. First group (n=18) received ultrasound (as control group), second group (n=18) received phonophoresis of 4mg dexamethasone ampoule and third group (n=19) received phonophoresis of 0.4% dexamethason gel. All groups were treated with an ultrasound program using stroking technique, pulse mode, 1.5 W/cm2, 5 minutes per session for 10 sessions. Visual Analog Scale (VAS) for pain severity and Western Ontario and McMaster universities Osteoarthritis Index (WOMAC) and the time up and go test (TUG) were evaluated before and after treatment in all groups.

Results: The VAS, total WOMAC and TUG scores were significantly improved after treatment in all groups (P<0.001). The group receiving phonophoresis of dexamethasone ampoule showed more significant effects in reducing pain and improving function and mobility among three groups.

Conclusion: Our results indicated that both ultrasound and phonophoresis of dexamethasone are effective methods in pain relief and improving function in mild and moderate knee osteoarthritis but phonophoresis of dexamethasone ampoule is better than the other treatments and it is suggested as an available method for treatment of knee osteoarthritis symptoms.