These changes alter the intrinsic mechanical properties of articular cartilage and produce swelling. 25 The articular cartilage, having lost some of its compressive ability under load, further degenerates. As the surface fibrillation progresses, the articular defects penetrate deeper into the cartilage until the cartilage is lost. The increased pressure on the subchondral bone causes it to thicken. Often bone cysts form deep to the eburnated areas. Eventually, bony nodules or osteophytes form at the periphery of the cartilage surface. All of these changes account not only for the pathology found on radiographs or histologically (findings under the microscope), but also for the joint pain, tenderness, loss of motion and stiffness of OA. 26 It is the relief of some of these clinical manifestations that accounts for the widespread use of NSAIDs not only in the United States, but around the world.
NSAIDS have antipyretic activity and can be used to treat fever.   Fever is caused by elevated levels of prostaglandin E2 , which alters the firing rate of neurons within the hypothalamus that control thermoregulation.   Antipyretics work by inhibiting the enzyme COX, which causes the general inhibition of prostanoid biosynthesis ( PGE2 ) within the hypothalamus .   PGE2 signals to the hypothalamus to increase the body's thermal set point.   Ibuprofen has been shown more effective as an antipyretic than paracetamol (acetaminophen).   Arachidonic acid is the precursor substrate for cyclooxygenase leading to the production of prostaglandins F, D & E.
Endometriosis implants are most commonly found on the ovaries, the Fallopian tubes, outer surfaces of the uterus or intestines, and on the surface lining of the pelvic cavity. They also can be found in the vagina, cervix, and bladder. Endometriosis may not produce any symptoms, but when it does the most common symptom is pelvic pain that worsens just prior to menstruation and improves at the end of the menstrual period. Other symptoms of endometriosis include pain during sex, pain with pelvic examinations, cramping or pain during bowel movements or urination, and infertility.