Hi Welcome to HCM The knee pain is commonly resulted of an arthritis. It is common with aging. The zorab is a proton pump inhibitor containing rabiprazole which is used for controlling acid levels in stomach. It is also prescribed with other drugs that can cause gastritis like NSAIDs which are anti inflammatory drugs and commonly used as pain killer e.g ibuprofen, diclofenic sodium, mefnamic acid. These drugs are very necessary in the treatment of arthritis and proton pump inhibitor are prescribed with them to prevent gastritis. However you doctor haven t prescribed anti inflammatory drugs which have a key role in the treatment of arthritis. You mother can use diclofenic sodium for arthritis along with acetaminophen as cure of arthritis. For best opinion visit orthopedic doctor. Thanks Regards