The hip joint is one of the most complex synovial joints in the body, and is the largest ball-and-socket joint in the body. It connects the pelvis to the thigh bone (femur), with the ball from the femoral head and the socket with the acetabulum. While the hip joint is designed to withstand a great amount of wear and tear, the joint is not indestructible and hip joint pain is common.
What can cause hip pain?
Hip pain is experience by approximately 11% of the general population. It can be caused by a multitude of factors, including but not limited to:
- Arthritis – juvenile idiopathic, rheumatoid, septic or osteoarthritis
- Injuries – bursitis, dislocation, hip fracture/labral tear, hernia, sprains and tendinitis
- Pinched nerves – meralgia paresthetica, sacroiliitis and sciatica
- Cancer – metastatic, bone cancer and leukemia
- Other conditions, such as osteoporosis
What is a hip joint nerve block?
A hip joint nerve block is a diagnostic steroid injection around the obturator and femoral nerve articular branches. These are done under fluoroscopic X-ray guidance and intravenous sedation to ensure optimal placement of the needle.
After the injection, you are to monitor for both a percentage of improvement to your symptoms, and how long these lasted for. The option exists to continue with short-term pain relief for re-administration of these injections, but this can lead to articular damage. If you experience an adequate amount of pain relief with these injections, a further treatment option exists for long-term relief that can be replicated at a much wider time interval compared to the nerve block.
What is hip joint radiofrequency ablation?
RF is a neurolytic technique that uses heat to produce controlled tissue destruction (thermocoagulation). The electrode tip is usually placed near the target nerve. A high frequency continuous electrical current (usually 100 to 1000 kHz) is then passed through the electrode, which heats up the surrounding tissue. The radiofrequency treatment will then entail creating a heat lesion around the identified nerves which will help to prevent pain signals from traveling to the brain. Radiofrequency application to those target nerves is a possible way to obtain longer pain relief.
How is the procedure performed?
You will be placed on the procedure table. The site to be injected is numbed with a local anaesthetic, and a needle is directed to the target area. X-ray guidance is used to ensure proper placement and positioning of the needle. Once the needle is properly positioned, radiofrequency waves are transmitted to the tip of the needle, which causes it to reach a temperature of 80 degrees Celsius. The needle tip is heated to this level for a period of time in order to complete the ablation process. This process is then repeated for each targeted nerve.
Will the procedure be painful?
The injection can be painful and we therefore provide light IV sedation. IV sedation, combined with local anaesthetic, can make the injection nearly pain free.
What are the discharge instructions?
If you have received IV sedation do not drive or operate machinery. You may return to work the next day following your procedure. You may resume your normal diet immediately. Do not engage in any strenuous activity for 24 hours. Call the office if you have any of the following: severe pain afterwards (different than your usual symptoms), redness/swelling/discharge at the injection site(s), fevers/chills, difficulty with bowel or bladder functions.
How long does it take for the procedure to work?
The healing process can take up to 6-8 weeks. As your nerve(s) heal from this procedure, the pain will continue to improve. The maximum benefit from this procedure is typically experienced about 6 weeks afterwards, and this typically lasts 8-12 months.
What are the risks and side effects?
The complication rate for this procedure is very low. Whenever a needle enters the skin, bleeding or infection can occur. Some other serious but extremely rare risks include paralysis and death.
You may have an allergic reaction to any of the medications used. If you have a known allergy to any medications, especially local anaesthetics, notify our staff before the procedure takes place.
You may experience any of the following side effects up to 4 hours after the procedure:
- Leg muscle weakness or numbness may occur due to the local anaesthetic affecting the nerves that control your legs (this is a temporary affect and it is not paralysis). If you have any leg weakness or numbness, walk only with assistance in order to prevent falls and injury. Your leg strength will return slowly and completely.
- Dizziness may occur due to a decrease in your blood pressure. If this occurs, remain in a seated or lying position. Gradually sit up, and then stand after at least 10 minutes of sitting.
- Mild headaches may occur. Drink fluids and take pain medications if needed. If the headaches persist or become severe, call the office.
- Moderate to severe discomfort at the injection site can occur. This can last for a couple weeks or longer, and is due to inflammation of ablated nerve(s). If this occurs, take anti-inflammatories or pain medications; apply ice to the area the day of the procedure. If it persists, apply moist heat in the day(s) following. The nerve(s) will heal slowly and the inflammation will resolve, leading to resolution of this pain caused by the procedure.
The side effects listed above can be normal. They are not dangerous and will resolve on their own. If, however, you experience any of the following, a complication may have occurred and you should either contact your doctor. If he is not readily available, then you should proceed to the closest emergency department for evaluation.
References:
Tinnirello et al 2018, ‘Pulsed Radiofrequency Application on Femoral and Obturator Nerves for Hip Joint Pain: Retrospective Analysis with 12-Month Follow-up Results’, Pain Physician, vol. 21 pp. 407-414.
