Kneecap dislocation is a deformity or injury to the knee joint in which the knee bends backward more than normal. Also known as knee hyperextension, this condition can be caused by congenital factors, sports injuries, or musculoskeletal problems.Kneecap dislocation is a deformity or injury to the knee joint in which the knee bends backward more than normal. Also known as knee hyperextension, this condition can be caused by congenital factors, sports injuries, or musculoskeletal problems.Kneecap dislocation is a deformity or injury to the knee joint in which the knee bends backward more than normal. Also known as knee hyperextension, this condition can be caused by congenital factors, sports injuries, or musculoskeletal problems.