Radiofrequency Ablation for Chronic Hip Pain: Reviewing the Evidence

Many people with osteoarthritis and other degenerative diseases, including posttraumatic pain and rheumatoid arthritis, suffer from chronic hip pain. Conservative treatment approaches such as physical therapy and analgesia may result in significant cost or adverse effects while providing only short-term improvement, and minimally invasive techniques have been found to be ineffective or of temporary benefit.¹

Although total hip arthroplasty (THA) is often performed in patients with advanced disease, the procedure is associated with a 5% to 15% failure rate, high cost, and increased morbidity, mortality, and persistent postoperative pain.^2-5 In addition, the life expectancy of hip implants ranges from 10 to 25 years.

There has recently been renewed interest in radiofrequency (RF) procedures for joint pain resulting from degenerative conditions.^6,7

“Clinical studies have shown that RF treatment is more effective than conservative methods in reducing hip pain,” said Edward Heres, MD, a pain medicine expert and clinical assistant professor of anesthesiology at the University of Pittsburgh Medical Center in Pennsylvania. “It works by interrupting the sensory input from the femoral and obturator nerves that innervate the hip joint,” he told Clinical Pain Advisor.

There remain several knowledge gaps, however, regarding patient selection, anatomic targets, long-term benefits, and other variables. A review published in Regional Anesthesia and Pain Medicine examined the evidence pertaining to RF for hip pain.⁵ The authors identified 14 articles regarding RF treatment targeting the hip joint. The overall quality of evidence was deemed to be low because of a lack of randomized controlled trials; all articles were case reports or series.

The most common indication for RF was osteoarthritis, and other diagnoses included vascular necrosis and persistent pain after THA. Participants had moderate to severe hip pain and limited ambulation, and previously demonstrated a lack of response to oral analgesics and other conservative approaches.

Technical Procedures

All studies used ablative RF, except for 2 that used pulsed RF. Most RF procedures targeted articular branches of the obturator nerve and femoral nerve. To guide placement of the RF cannulas, all but 1 of the studies used fluoroscopy, which “is considered mandatory for improving the accuracy of ablation of articular branches of this nerve innervating the hip joint,” the authors wrote.

In all studies that involved procedures on the articular branches of the obturator nerve, the imaging landmark for needle placement was “the point immediately inferior to the ‘teardrop’ silhouette, formed by the junction of pubic and ischial bones (often referred to as the incisura of the acetabulum),” they noted. For procedures involving the articular branches of the femoral nerve, the imaging landmark was a “point immediately inferior and medial to the anterior inferior iliac spine [that] corresponds to the anterolateral aspect of the extra-articular portion of the hip joint.”

Patient Outcomes

All studies demonstrated reductions in pain scores after RF treatment, ranging from 30% to more than 90%. The length of follow-up varied considerably across studies, from 8 days to 3 years. Although most of the articles reported reductions in analgesic requirements after RF, these changes were not quantified. The few adverse effects that occurred “were usually due to vascular penetration or inadvertent ablation of extra-articular sensory and motor branches of the [obturator nerve and femoral nerve],” noted the review authors.

Although some results suggested improved function after RF, few of the studies used validated measures for this outcome. One prospective study from 2012, which found a 33% reduction in visual analogue scale scores, also observed a 16% reduction in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores and a 34% improvement in Harris Hip Scores.⁸ In a prospective nonrandomized open-label study published in 2015, greater improvements in Oxford hip scores were noted at 1, 4, and 12 weeks in patients who received RF vs conservative treatment.⁹

The review also describes the innervation pattern of each nerve suggested as a target for RF ablation in specific types of hip-related pain, as well as recommended approaches for ablation at these sites: the articular branches of the obturator nerve for groin and thigh pain, the articular branches of nerves innervating the posterior hip joint for gluteal pain, and the articular branches of the femoral nerve for thigh and trochanteric pain.

“Hip pain is a common condition that is often seen in elderly patients with multiple comorbidities,” Dr Heres noted. “Often, pain medications are ineffective or have too many side effects, and injections only provide little or temporary pain relief.” In addition, surgery may not be an option because of unwillingness of the patient or an especially high risk for complications related to comorbidities. RF treatment may be a reasonable alternative in these circumstances, as well as in situations involving long wait times for THA or persistent pain after THA.

“Additional randomized controlled clinical studies involving greater numbers of patients are needed,” said Dr Heres.

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References

1. Flanagan J, Thomas TL, Casale FF, Desai KB. Intra-articular injection for pain relief in patients awaiting hip replacement. Ann R Coll Surg Engl. 1988;70(3):156-157.
2. Hip and Knee Replacements in Canada: Canadian Joint Replacement Registry 2013 Annual Reports. https://secure.cihi.ca/estore/productFamily.htm?pf=PFC2209&lang=en&media=0 Accessed March 21, 2018.
3. Grayson CW, Decker RC. Total joint arthroplasty for persons with osteoarthritis. PM R. 2012;4(5 Suppl):S97-S103.
4. Belmont PJ Jr, Powers CC, Beykirch SE, Hopper RH Jr, Engh CA Jr, Engh CA. Results of the anatomic medullary locking total hip arthroplasty at a minimum of twenty years: a concise follow-up of previous reports. J Bone Joint Surg Am. 2008;90(7):1524-1530.
5. Bhatia A, Hoydonckx Y, Peng P, Cohen SP. Radiofrequency procedures to relieve chronic hip pain: an evidence-based narrative review. Reg Anesth Pain Med. 2018;43(1):72-83.
6. Bhatia A, Peng P, Cohen SP. Radiofrequency procedures to relieve chronic knee pain: an evidence-based narrative review. Reg Anesth Pain Med. 2016;41(4):501-510.
7. Santana Pineda MM, Vanlinthout LE, Moreno Martín A, van Zundert J, Rodriguez Huertas F, Novalbos Ruiz JP. Analgesic effect and functional improvement caused by radiofrequency treatment of genicular nerves in patients with advanced osteoarthritis of the knee until 1 year following treatment. Reg Anesth Pain Med. 2017;42(1):62-68.
8. Rivera F, Mariconda C, Annaratone G. Percutaneous radiofrequency denervation in patients with contraindications for total hip arthroplasty. Orthopedics. 2012;35(3):e302-e305.
9. Chye CL, Liang CL, Lu K, Chen YW, Liliang PC. Pulsed radiofrequency treatment of articular branches of femoral and obturator nerves for chronic hip pain. Clin Interv Aging. 2015;10:569-574.