Hip joint injections for pain relief

Pain caused by the hip joint
The hip joint is a large joint where the leg joins the pelvis. If this joint experiences arthritis, injury or mechanical stress, one may experience hip, buttock, leg or low back pain. A hip joint injection may be considered for patients with these symptoms. The injection can help relieve the pain, as well as help diagnose the direct cause of pain.

Hip joint injections involve injecting medicine directly into the joint. These injections can help diagnose the source of pain, as well as alleviate the discomfort:

Diagnostic function: By placing numbing medicine into the joint, the amount of immediate pain relief experienced will help confirm or deny the joint as a source of pain. If complete pain relief is achieved while the hip joint is numb it means this joint is likely to be the source of pain.
Pain relief function: Along with the numbing medication, time-release cortisone is also injected into these joints to reduce inflammation, which can often provide long term pain relief.

Anatomy of the hip joint
The hip joint is a ball and socket joint located where the thigh bone meets the pelvis. The top of the thigh bone (the femur) is a round ball, which fits into the socket formed by a cavity in the pelvic bone. The ball is held in the socket by a grouping of ligaments that form a capsule around the joint. This capsule of ligaments contains synovial fluid which acts as a lubricant. There is cartilage between the two bones, which allows them to move against each other without causing friction.

Hip joint injection procedure
Fluoroscopy (live x-ray) is commonly used in hip joint injections for guidance in properly targeting and placing the needle, and for avoiding nerve or other injury.

On the day of the injection, patients are advised to avoid driving and doing any strenuous activities.

The hip joint injection procedure includes the following steps:

An IV line will be started so that adequate relaxation medicine can be given, if needed.
The patient lies face down on an x-ray table and the skin over the hip is well cleaned.
The physician numbs a small area of skin with an anesthetic (a numbing medicine). The patient may feel a sting that will last for a few seconds.
The physician uses x-ray guidance (fluoroscopy) to direct a very small needle into the joint. Several drops of contrast dye are then injected to confirm that the medicine only reaches the joint.
A small mixture of anesthetic and anti-inflammatory cortisone is then slowly injected into the joint.

The injection itself only takes a few minutes, but the overall procedure will usually take between thirty and sixty minutes.After the hip joint injection procedure, the patient typically remains resting on the table for twenty to thirty minutes, and then is asked to move the area of usual discomfort to try to provoke the usual pain. Patients may or may not obtain pain relief in the first few hours after the injection, depending upon whether or not the joint that was injected is the main source of the patient’s pain. On occasion, the patient may feel numb or experience a slightly weak or odd feeling in the leg for a few hours after the injection.

The patient will discuss with the doctor any immediate relief of pain, and will then record the levels of pain relief during the next week. A pain diary is helpful to clearly inform the treating physician of the injection results and in planning future tests and/or pain management treatment, as needed.

Pain relief after a hip joint injection
Patients may notice a slight increase in pain lasting for several days as the numbing medicine wears off and the cortisone is just starting to take effect. If the area is uncomfortable in the first two to three days after the injection, applying ice or a cold pack to the general area of the injection site will typically provide pain relief and appear more beneficial than applying heat.

If the hip joint that was treated is the source of the pain, the patient may begin to notice pain relief starting two to five days after the injection. If no improvement occurs within ten days after the injection, then the patient is unlikely to gain any pain relief from the injection and further diagnostic tests may be needed to accurately diagnose the patient’s pain.

Patients may continue to take their regular medicines after the procedure, with the exception of limiting pain medicine within the first four to six hours after the injection, so that the diagnostic information obtained is accurate. Patients may be referred for physical therapy or manual therapy after the injection while the numbing medicine is effective and/or over the next several weeks while the cortisone is working.

On the day after the procedure, patients may return to their regular activities. When the pain has improved, it is advisable to start regular exercise and activities in moderation. Even if the pain relief is significant, it is still important to increase activities gradually over one to two weeks to avoid recurrence of pain.

Potential risks of hip joint injections
As with any procedure, there is a risk of complications. Possible side effects from the hip joint injection include:

Allergic reactions to the medications used
Infection (occurs in less than 1 per 15,000 injections)
Post-injection flare (joint swelling and pain several hours after the corticosteroid injection)
Depigmentation (a whitening of the skin)
Local fat atrophy (thinning of the skin)
Rupture of a tendon located in the path of the injection

By: Ray M. Baker, MD
August 23, 2005