Damage to the veins seldom causes a serious problem. Below the knee, one can usually tie off veins with impunity. Damage to major veins above the knee may result in limb swelling and, if possible, one should attempt to reconstruct them. Both veins and arteries can be damaged during surgical procedures and early recognition and treatment is essential. Direct damage to the veins can also occur when bones are broken, following an assault in which the limb is stabbed, or following gunshot injuries.