Knock knee deformity or genu valgum may be caused by a number of different conditions including metabolic diseases, renal failure, trauma and infection. It may also be idiopathic, that is, having no known cause.
Treatment usually consists of guided growth, rather than osteotomy, with a plate and screws placed on the medial side of the knee — the opposite side from that used to correct bow leg deformity. [Figure 3]
The specific device used to achieve guided growth is the Eight Plate. This consists of a small, two-hole figure eight plate and two screws, one on each side of the growth plate.