Genu recurvatum is a deformity in the knee joint, so that the knee bends backwards. In this deformity, excessive extension occurs in the tibiofemoral joint. Genu recurvatum is also called knee hyperextension and back knee. This deformity is more common in women[citation needed] and people with familial ligamentous laxity. Hyperextension of the knee may be mild, moderate, or severe.
Normal range of motion (ROM) of the knee joint is from 0 to 135 degrees in an adult. Full knee extension should be 0 degrees. In genu recurvatum (back knee), normal extension is increased. The development of genu recurvatum, may lead to knee pain and knee osteoarthritis.