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