<prompt> The most common site of primary osteoarthrosis is -Hip jointKnee jointAnkle jointShoulder joint  <response>: In general, weight bearing lower limb joints are affected more commonly than upper limb joints.However, No textbook has mentioned which is the commonest joint : knee or hip.According to me it is knee because of following facts :-I have seen hardly one or two cases of primary OA of hip; while, I have seen hundreds of cases of Primary OA of knee in my OPD. At least 4 to 5 patients of primary OA of knee comes daily to my OPD.OA commonly affects the knee joint EbnezarOA of hip is second in frequency to the knee joint Ebnezar 