You may have pinched or injured blood vessels if your knee, lower leg, or foot turns pale, white, blue, or cold after a knee injury.
Symptoms that begin after a knee splint has been applied may mean that the splint is too tight, causing blood flow to be reduced or restricted. Loosen the splint if you have these symptoms. A health professional may need to adjust your splint or treat other damage.
Prompt treatment to restore blood flow will help prevent severe complications.
WebMD Medical Reference from Healthwise