You may not like the idea of getting a shot, but injections often help relieve pain and inflammation and help improve joint movement. To control your pain, your doctor can inject medication directly into the problem area instead of prescribing pills to be taken by mouth. Injections are not a cure, but they can help you through a period of intense pain. Often, injections offer an alternative to patients whose only other choice to relieve pain is surgery. Injections also offer relief to patients for whom surgery is not a viable option because of other health conditions. Injections are used to relieve knee pain, low back pain, hip pain, and many other conditions resulting from acute injuries, overuse injuries, and medical conditions such as arthritis.

What are injections used for?
Injections can be used to diagnose as well as to treat injuries and illnesses. Injections are sometimes used to learn more about what is causing your pain and how it can be treated. For example, if an injection provides pain relief in the area that is injected, it is likely that the area is the source of the problem. On the other hand, if the injection does not relieve the pain at the injection site, the pain could be the result of nerve damage, which can mean the pain traveled to that area of the body from another area. Therapeutic injections are used as treatments for temporary relief from pain and are typically divided into 3 categories based on the part of the body that is injected. Joint injections, soft tissue injections, and nerve block injections are common treatments for the relief of inflammation and pain.

Joint Injections
An adult over age 45 often experiences arthralgia or joint pain. Many types of injuries or conditions can cause joint pain. For example, rheumatoid arthritis is an autoimmune disorder that causes pain and stiffness in the joints, and osteoarthritis involves the growth of bone spurs and degeneration of cartilage at the joint, causing severe pain. An injection of corticosteroid medication is often prescribed to help relieve the pain caused by different types of arthritis, or it can be prescribed after an injury or surgery.

Corticosteroid medications imitate the effects of the hormones cortisone and hydrocortisone, which are produced by your adrenal glands. Corticosteroids can be injected into affected joints, such as the shoulder, elbow, hip, or knee, and can relieve pain for 4 to 6 months.

Injections are often given in the hip joint to relieve pain resulting from arthritis (Fig. 1). The most common disease that affects the hip, arthritis is a degenerative disease that can cause pain, stiffness, inflammation, and damage to the joint cartilage (the smooth tissue at the ends of bones that allows them to glide against one another). Such damage can lead to joint weakness, instability, and visible deformities that can interfere with basic daily tasks such as walking, climbing stairs, sitting, rising from a chair, or getting out of bed.

Usually, 3 injections of a corticosteroid are given over a 3-week period. The procedure is performed under fluoroscopy (visual diagnostic examination on a screen or monitor) while the patient lies on his or her back on the fluoroscopic table. After the hip is cleaned with iodine and alcohol, the needle is advanced into the hip joint. Often, a small amount of water-soluble contrast (dye) is injected to confirm proper needle location. Then, the needle is slowly withdrawn. The entire procedure only takes minutes, but the benefits can last for months.

Soft tissue injections
Bursitis, or inflammation of the bursa, causes nagging joint pain. You have more than 150 bursae (small, fluid-filled sacs) in your body, which cushion the pressure points between your bones and the tendons and muscles near your joints. When a bursa becomes inflamed, movement or pressure on the affected joint can be painful. Bursitis most often affects the shoulder, elbow, or hip. Injections of corticosteroid can help reduce the inflammation and pain (Fig. 2).

Trigger point injections
Trigger point injections are prescribed when your muscles are sensitive and painful to the touch. Depending on the medication used, trigger point injections can reduce pain and inflammation in your muscle or can relax a muscle. A combined injection of anesthetic and corticosteroid medication can reduce pain and promote increased range of motion. Because the corticosteroid can take 3 to 4 days to begin reducing the inflammation and providing relief, anesthetic is also given for the pain until the inflammation can be controlled. Sometimes an anesthetic alone is used if there is little or no inflammation and the goal is to relax the muscle for effective stretching.

Nerve block injections
A nerve block prevents pain messages from traveling along a nerve pathway and reaching your brain. Nerve blocks are often used to relieve pain for a short period, such as during surgery. If there is inflammation around a nerve, an injection of corticosteroid medication in conjunction with the nerve block anesthetic can provide longer relief.

There are 3 major types of nerve blocks, peripheral, spinal, and sympathetic. Peripheral injections are used for localized pain and are injected away from the spine. For pain that affects a broad area, an anesthetic is injected in or near the spine. An injection directly into the spinal fluid is called an intrathecal injection. An intrathecal injection is often used during surgery on the abdomen or legs.

The sympathetic nervous system controls circulation and perspiration and are part of your autonomic nervous system. An injection of an anesthetic to block the sympathetic nerves can relieve chronic pain caused by diseases such as complex regional pain syndrome, which affects your sympathetic nervous system.

Side effects
You can experience side effects after an injection, such as an infection, an allergic reaction, local bleeding, or skin discoloration. Not everyone develops side effects, and symptoms vary from person to person. Side effects rarely occur if injections are given less than every 3 to 4 months. However, if injections are given more frequently you could experience weakened ligaments, tendons, and bones.

Some people simply don't like shots, while others have serious phobias about injections. Despite any fear you may have, if your doctor recommends an injection, you should consider the benefits. You may experience some pain initially during the procedure, but that only lasts minutes. On the other hand, if you have the injection, you could get a shot of relief that lasts for months.

Garland K. Gudger, MD
Columbus, Georgia