You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is The most common site of primary osteoarthrosis is - and explain in detail?
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