There is no rule as to how many cortisone injections can be given. Often physicians do not want to give more than three, but there is not really a specific limit to the number of shots. However, there are some practical limitations. If a cortisone injection wears off quickly or does not help the problem, then repeating it may not be worthwhile. Also, animal studies have shown effects of weakening of tendons and softening of cartilage with cortisone injections. Repeated cortisone injections multiply these effects and increase the risk of potential problems. This is the reason many physicians limit the number of injections they offer to a patient.