Hip joint injections involve injecting medicine directly into the hip joint to diagnose the source of pain or treat pain due to conditions such as arthritis, injury or mechanical stress of the hip joint. Hip pain may be experienced in the hip, buttock, leg or low back. The injection contains a combination of a numbing medicine and cortisone (an anti-inflammatory agent). Numbing medicine delivers temporary relief from pain, provided the hip joint is the source of the pain. It thus serves a diagnostic function and helps to confirm or deny whether the joint is the source of pain. Cortisone serves to reduce the inflammation in the joint providing long term pain benefit.