Background and aim: The great amount of load tolerated by the knee joint during daily activities has made this joint the most vulnerable joint to osteoarthritis. Different types of knee orthosis are prescribed for treatment and among them neopran and 3 pressure points orthosis are the most common ones. Although these orthosis are used widely, little is known about their effects on the relief of patient's symptoms. In this study the immediate effects of two "4 spring-loaded neopran" and "3 pressure points corrective" knee orthosis on the pain reduction and functional improvement of the patients suffering from medial compartment knee orthosis were compared.

 Materials and methods: Twenty patients (age 53±12) with medial compartment knee osteoarthritis, with severity of less than grade 4 (based on the Kellgren & Lowrence grading method and diagnosis of an orthopedist) and tibiofemoral angle of above 180º were recruited. The functional performance was assessed by 6 min walking test in the first day without orthosis and in the 2^nd and 3^rd day immediately after wearing one of the orthosis in random order. The intensity of pain was evaluated by 100 mm VAS test in the first day before and after 6 min walking test and in the 2^nd and 3^rd day only after the walking test.

 Results: Both orthosis induced a significant reduction in patient's pain (p<0.01) and improvement in functional capacity (p<0.01). the comparison between the two orthosis regarding the pain reduction after the walking test revealed the dominance of the 3 pressure points corrective orthosis (p<0.007). The difference between the functional improvements of two knee orthosis was statistically not significant (average increase in walking distance of 15 m and 24 meters for neopran and 3 pressure point orthosis).

 Conclusion: The 3 pressure point and neopran knee orthosis can induce significant reduction in pain and improvement in the functional capacity of the patients with medial compartment knee osteoarthritis. The 3 pressure point orthosis seems to dominate the neopran in pain reduction and functional improvement (however not statistically significant).