Osteoarthritis of knee Illustration of a front view of a human left knee joint affected by osteoarthritis The knee cap patella has been removed The cartilage white at the end of the thigh bone femur at top has worn away in patches Irregular bony outgrowths called osteophytes have grown at the top of the shin bone tibia The fibrous white tissues are tendons and ligaments which hold muscles and bones together inside joints Osteoarthritis results from wear and tear of joints It is most common in the elderly and obese Deterioration of joints causes pain stiffness and lack of mobility Treatment includes drugs and surgery