Knee pain is one of the most prevalent reasons for doctor office visits.  The most common causes of knee pain are injuries, obesity, inflammation, aging, and arthritis, The most common causes of injuries are torn ACL (anterior cruciate ligament), MCL (Medial collateral ligament), posterior cruciate ligament, torn Meniscus, and patellar fractures. The most common causes of Knee arthritis are Rheumatoid arthritis and Osteoarthritis. Diagnosis includes CT scan and MRI and x-rays.  Treatment options include Corticosteroid injections, hyaluronic injections, stem cells, and platelet-rich plasma (PRP) injections. Surgery is reserved for arthroscopic procedures, ACL, MCL, PCL repairing, Meniscus repair, and partial knee replacement. and total knee replacements.