The most common site of primary osteoarthrosis is -
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"   —Ebnezar
"OA of hip is second in frequency to the knee joint" —Ebnezar
Hip joint
Knee joint
Ankle joint
Shoulder joint