Why at 23 do I have severe arthritis in my knees?
No sorts, injuries or family history. Healthy thin female
This is a tough question to answer. It is unclear from your question what symptoms you are having. For example a doctor will want to know if you are having pain, what type of pain, what time of day is it worse, anything make it better, and anything make it worse? I imagine you are having pain in your knees, which you have equivocated to arthritis. You are correct in that arthritis in the knees of a 23 year old is quite rare. For this reason, I am suspicious that your symptoms are probably due to something other than arthritis. The most common type of persistent knee arthritis in young people is rheumatoid arthritis. Another cause that is temporary is viral synovitis, an infection of the knee which can cause pain. I suggest that you schedule an appointment with your primary care physician. He or she can take a detailed history of your symptoms and perform a thorough musculoskeletal exam focusing on your knees. From there you may get a imaging of your knees (such as an x-ray), and/or and anti-inflammatory drug which can help with the pain. If anything is seen on the imaging, then you may warrant a referral to an orthopedic surgeon.