When you are deciding whether to call the doctor, a good rule of thumb exists for most long-term knee injuries. If your symptoms have not gone away after trying three to seven days of PRICE therapy and over-the-counter anti-inflammatory pain medications , you should set up an appointment with your doctor or a sports medicine or orthopedic (bone and muscle) specialist to further evaluate the pain. This rule can also be applied to new knee injuries that are not disabling. Any knee injury that makes it impossible for you to walk should be evaluated as soon as possible. Remember, however, that this rule should only serve as a guide. If you are concerned about the pain, you should call the doctor.