Knee joint steroid injection For example, if the height of a matchbook represents the amount usually seen by your cells, your doctor wants to inject an amount equivalent to the height of the Empire State Building. The needle is then removed. Pain may be relieved for several days to several months, allowing you to participate in physical therapy. You may notice a slight increase in pain as the numbing medicine wears off and before the corticosteroid starts to take effect. If such a fracture does occur, depending on your age and overall health, you may require surgery or extensive periods of inactivity, which may increase your risks for other health conditions. What happens before treatment?