A Knock Knee Splint is a piece of plastic or wood that is placed over the knees to keep them straight. A splint may be used while you are sleeping to keep the knees straight. Knock knee can be caused by an underlying congenital or developmental disease or arise after an infection or a traumatic knee injury. It is a corrective knee brace often used for knock knees arthritis where the deformity is due to knee osteoarthritis. Knock Knee Splint is very useful.