Image-Guided Hip Injections

Journal of Novel Physiotherapy and Physical Rehabilitation

Review Article

Authors: Drs Evren Yasar, Jaspal R Singh, John Hill, and Venu Akuthota

Hip pain is a common type of joint pain. It is sometimes treated with medications that are injected directly into the joint or the soft tissue next to a joint (often called a bursa). The goal of the injection is to reduce inflammation and provide pain relief.

In the September 2014 edition of the Journal of Novel Physiotherapy and Physical Rehabilitation , Drs Evren Yasar, Jaspal R Singh, John Hill, and Venu Akuthota reviewed the use of ultrasound and fluoroscopy for guiding injections about the hip joint.

What causes hip pain?

The hip is designed to allow for fluid movement and withstand a fair amount of wear and tear. With age, excessive use, or injury, the cartilage, tendons, muscles, and hip bone itself can become worn or damaged, causing pain.

The hip joint (the largest ball-and-socket joint in the body), pelvis, and surrounding muscles have a complex anatomical relationship with other structures in the body, including the spine and legs. Thus, a condition affecting the spine or legs may cause hip pain.

How is hip pain diagnosed?

In diagnosing hip pain, physicians seek to understand the pain’s character and source. For instance, pain found in the front of the hip or groin often suggests the hip joint itself is the cause. Pain on the outside point of the hip that worsens with direct pressure may be due to a condition called trochanteric bursitis. Disorders of the facet joints and hip joints, as well as lower back pain, may also cause pain in the groin or hip; this pain typically originates at the waistline or buttocks.

The source of hip pain is determined by a physical examination. However, some patients may require additional diagnostic imaging such as X-ray, magnetic resonance imaging (MRI), computerized tomography (CT), or ultrasonography.

Also, several injection techniques are helpful to learn the conditions causing hip pain. These injection techniques may be used to deliver therapeutic medications, assess joint function, or remove fluid from the space around a joint.

A hip injection is a difficult procedure, so it is often performed with the guidance of fluoroscopy or ultrasound.

How can hip injections be beneficial?

Hip injections have two purposes: to better understand the source of hip pain and alleviate hip pain with the delivery of medications.

Increasingly, injections to the hip joint are used to help physicians make clinical decisions. For instance, before considering surgery on the cartilage around the hip socket, surgeons often perform a joint injection to look for a positive response to anesthetic.

Injecting local anesthetics delivers a nerve block to the hip joint. The nerve block can be a valuable diagnostic tool because it helps determine if the hip pain is related to osteoarthritis, bursitis, a compressed spinal nerve, or other lower back dysfunctions. If pain is significantly diminished within minutes after the local anesthetic injection, it can be determined that the cause of the hip pain is within the hip joint itself.

Hip injections may deliver one or several medications to alleviate pain:

• Corticosteroids (anti-inflammatory medications): eg, betamethasone, triamcinolone
• Local anesthetics (numbing medications to temporarily inhibit pain): eg, procaine, lidocaine, bupivacaine
• Other additives: sodium bicarbonate (to speed up the onset of local anesthesia), epinephrine (to prolong nerve blockade)

What are image-guided injections?

To ensure the injection goes into the hip joint itself—where it has a better chance of working—the needle for the injection is guided by imaging, most often ultrasound or fluoroscopy.

Ultrasound provides real-time radiographic imaging of the musculoskeletal system and can provide very detailed images of deep-seated joints, muscles, and tendons.

Fluoroscopy offers immediate and ongoing imaging of the motion of internal structures. A continuous X-ray beam is passed through the body part being examined. The beam is transmitted to a TV-like monitor so that the body part and its motion can be seen in detail.

Whatever the method, fluoroscopy or ultrasound, the diagnosis of hip and pelvic conditions must be based on a thorough patient history and physical examination. Guided injections may provide additional information and can be an added tool for treating pain and restoring function and mobility.

How are hip injections performed?

1. The patient is placed in a comfortable and relaxed position with the affected hip exposed.
2. The skin overlying the hip bone is thoroughly cleaned and draped in a sterile fashion.
3. Through palpation (touch), fluoroscopic and ultrasound imaging, the bones, nerves and arterial landmarks of the hip joint are defined.
4. The needle pathway is mapped and the entry point on the skin is marked.
5. A local anesthetic is delivered to the hip joint using a small caliber needle, significantly reducing patient discomfort.
6. A spinal needle is then inserted and directed towards the hip joint.
7. Once the needle has entered the hip joint, contrast is injected into the joint to confirm proper needle placement and proper spread of medication.
8. The physician then delivers a combination of corticosteroid and local anesthetic to the hip joint under fluoroscopic and ultrasonic imaging.
9. The needle is then removed, and a sterile bandage is placed over the injection site.

Intraarticular (within the joint) injection

Reasons to perform this type of injection

Hip osteoarthritis (OA) is a common cause of disability and diminished quality of life in older individuals and 8% of the general adult population. Hip OA can cause loss of joint cartilage, changes in the fluid, ligaments, and muscle mass surrounding the hip joint, as well as the formation of osteophytes (also known as bone spurs).

An intraarticular injection of local anesthetic with or without steroids can help determine if the hip joint itself is causing the hip pain.

Complications

Complications from this type of hip injection include the accidental injection of local anesthetics into a blood vessel or the spinal canal. Local anesthetics can also cause toxicity to skeletal muscle and joint cartilage. These can result in muscle weakness and decreased function.

Complications from intraarticular hip injections include joint infection and bleeding. However, strict adherence to aseptic (sterile) techniques and the use of image guidance can minimize these risks. Rarely, air embolism or mild pain and swelling at the injection site can occur. An increase in pressure within the joint could result in a limited functional range of motion.

Hip injections, especially with steroids, should not be done if the patient has bleeding/clotting disorders, systemic infection, uncontrolled diabetes and other uncontrolled cardiovascular disease. Furthermore, fluoroscopy for image guidance should not be used on pregnant patients.

Ischial bursa injection

Reasons to perform this type of injection

Ischial bursitis is a painful condition of the buttock and area over the ischial tuberosity, or “sitting bones”. The ischial bursa is located deep within the gluteus maximus muscle and overlies the sitting bones. As a result of repetitive trauma or acute damage, the bursa may become inflamed and painful. Pain in this region may also be related to chronic hamstring injuries.

An initial therapy program consisting of anti-inflammatory medications and stretching may benefit most patients. However, when those treatments do not help, a steroid injection into the ischial bursa may be performed.

Complications

Complications of ischial bursa injections may include local injection site pain and swelling. Also, if some of the anesthetic travels toward the sciatic nerve, the patient may feel numbness in the thigh and calf. A rare complication is weakness of muscles supplied by the sciatic nerve due to the inadvertent injection into the sciatic nerve.

Techniques

• Ischial bursa hip injection with fluoroscopic imaging
• Ultrasound-guided ischial bursa/hamstring injection

Greater trochanter bursa injection

Reasons to perform this type of injection

Greater trochanter pain syndrome is defined as a chronic, intermittent pain and tenderness over the greater trochanter with the patient in the side-lying position. Causes include bursitis and injuries to tendons or the gluteal muscle.

There is an increased prevalence of greater trochanter pain in older patients, female patients, and those with knee OA, obesity, and low-back pain. These risk factors may impact leg movement which can result in greater trochanteric bursitis. It is reported to affect 10-25% of the general population.

Complications

Complications include inadvertently delivering injectate too close to the gluteus medius bursa, which can cause numbness in the buttock.

Techniques

• Ultrasound-guided greater trochanter bursa injection
• Greater trochanter bursa injection using fluoroscopy

Piriformis Injection

Reasons to perform this type of injection

Piriformis syndrome is sometimes referred to as “back pocket sciatica.” People that keep a wallet in their back pocket and sit on it throughout the day often develop symptoms of pain in the buttock and down the leg. The extra pressure on the buttocks can cause tightening of the buttock muscles which can compress the sciatic nerve. The piriformis muscle is a small muscle located deep in the buttock (behind the gluteus maximus). The primary action of this muscle is external rotation of the femur (thigh bone). Symptoms of piriformis syndrome consist of buttock pain, with or without thigh pain, which is typically made worse with prolonged sitting.

A piriformis injection of anesthetic with or without steroid can provide a safe and effective way to diagnose and alleviate the pain. Some recent data has advocated the use of botulinum toxin (Botox) in patients with diagnosed piriformis syndrome. In 2007, Yoon et al. injected 20 patients with botulinum toxin using CT guidance. This group was compared to nine control patients receiving corticosteroid. Pain intensity scores were significantly lower in the botulinum group at all follow-up time points.

Techniques

• Fluoroscopy-guided piriformis muscle injection
• Ultrasound-guided piriformis muscle injection
• Piriformis muscle injection using nerve stimulator guidance

Nerve stimulator (or electrical stimulation) guidance can be used to guide muscle injections and nerve blocks. A needle electrode is connected to a nerve stimulator which delivers 0.8 mA. It is inserted and advanced slowly. Once appropriate twitches of the muscle are elicited, local anesthetic with steroid is injected.

Iliopsoas tendon/bursa injection

Reasons to perform this type of injection

Iliopsoas tendinosis—chronic injury of the hip flexor tendon—is often seen with rheumatoid arthritis, acute trauma, overuse injury, or after total hip replacement. Inflammation of the bursa, which is between the tendon and the pelvis or hip, can contribute to this situation.

Because of the proximity between tendon and bursa, the inflammation of one will inevitably result in inflammation of the other. Although rare, snapping hip may also be associated with iliopsoas bursitis and tendinitis. As a cause of pain after total hip replacement, impingement of the iliopsoas tendon reportedly occurs in up to 4.3% of patients.

Techniques

• Fluoroscopy-guided iliopsoas tendon/bursa injection
• Ultrasound-guided iliopsoas tendon/bursa injection

Blocks of the obturator and femoral nerves

The hip joint is supplied by the obturator, femoral and sciatic nerves. There are reports of short-term hip pain relief with an obturator nerve block. However, others have suggested that only blocking the obturator nerve may not be sufficient for the treatment of hip pain and that effective nerve block of the hip joint can only be achieved by also blocking the femoral nerve.

Techniques for obturator and femoral nerve blocks include CT, fluoroscopic, and electrical stimulation guided injections

Conclusion

At present, image-guided injections used to diagnose and treat the hip joint are recommended to promote safety and accuracy of interventions.

Intraarticular hip injections with fluoroscopy are used safely for both diagnostic and therapeutic interventions. Ultrasonography can visualize soft tissue structures and provide real-time images of various structures.

Whatever the imaging technique (fluoroscopy or ultrasound), diagnosing hip and pelvic disorders must rely on a thorough history and physical examination. Guided interventions may provide additional diagnostic information and used to treat pain and restore function and mobility.

Keywords

Bursitis: Inflammation of the bursa.

Bursa: The fluid-filled sac near a joint.

Facet joints: The small joints located between each vertebra that provide the spine with both stability and flexibility.

Greater trochanter: The outside point of the hip.

Snapping hip: A condition that causes a snapping sound or a snapping sensation in the hip, may also include pain and weakness that interferes with function.

References

The full list of references cited in this article can be found in the original publication.