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Authors; Amanda Shane, and Sharon Bailey.
Chronic pain is characterized as pain lasting longer than 3 months.1 An estimated 20% of Canadians are living with chronic pain, with 2 thirds experiencing moderate to severe pain and half experiencing long-term pain of over 10 years.2 Chronic pain is recognized as a health condition in the 11th revision of the International Classification of Diseases.3 It can be classified as chronic primary pain (pain associated with significant emotional distress and not otherwise accounted for by another diagnosis), or chronic secondary pain (pain as a symptom of another underlying health condition such as osteoarthritis).2 Current treatments for chronic pain are typically multipronged and may include pharmaceutical, psychological, physical and rehabilitation, medical devices, practitioner administered or manual therapy, and/or interventional pain procedures.2
Radiofrequency ablation (RFA) was introduced in the 1970s to treat back pain (via lumbar medial branch nerves of the facet joints),4 and then its use was expanded to treat a range of conditions, including sacroiliac joint pain in the 1990s,4 and chronic knee pain in 2008.5 RFA is a procedure that disrupts the transmission of pain signals through the delivery of targeted thermal damage to nearby neural tissue.6 Ideally, the chronic pain experienced by the patient will be attenuated while the damaged nerve structure is repaired by the body.6 The duration of pain relief varies but is considered temporary and may last anywhere from 3 to 6 months,7 or up to 12 months, or more.8 A radiofrequency probe is inserted typically via fluoroscopic guidance, but sometimes via ultrasound guidance, adjacent to target nerve(s) and generates radiofrequency energy, which manifests as ionic heating (heating of the surrounding tissue, not the probe itself), causing destruction of the nerve(s).6Target temperatures typically range from 80°C to 90°C, for 90 to 120 seconds, but there is variation in procedure parametres.9
In addition to conventional (or thermal monopolar) RFA, there are other modalities available, each with the same overall objective of reducing pain through temporary damage of target nerves. Cooled RFA involves probes that allow the circulation of saline around the probe tip to help carry heat away from the tissue interface and thus reduce heat-related tissue damage. This also results in a larger heating area and lesion, because more energy can be delivered through the probe.6 Therefore, more denervation is possible. Bipolar RFA involves 2 symmetrically placed electrodes that act as a conduit, also for the purpose of creating larger lesions than conventional RFA.10 Pulsed RFA was more recently introduced (late 1990s) as an alternative to conventional RFA. This procedure involves the production of pulses of 45V lasting 20 milliseconds at a maximum tissue temperature of 42°C. Evidence suggests that pulsed RFA is less painful and causes less tissue damage compared to conventional RFA, but the duration of pain relief is generally less than RFA.9 While pulsed RFA has similar effects on neural conduction, the treatment mechanism is different than that of nonpulsed RFA.
Often, a combination of conservative treatment interventions (e.g., activity modification, intra-articular steroid injections, nonsteroidal anti-inflammatory drugs, etc.) effectively reduce chronic noncancer pain in the short-term (3 to 6 months).11 Surgical interventions are an option for longer term pain relief or curative treatment, but some patients may not be eligible and those who are eligible may be faced with long surgical wait times.12 This often results in the reliance on pharmaceuticals like opioids for pain relief. Therefore, the availability of alternative nonpharmaceutical (e.g., non-opioid) treatment options are required. Indeed, there is evidence that treatment with RFA among patients with chronic axial spine pain is associated with a decrease in the proportion of patients with opioid prescriptions compared to the proportion preprocedure.13 However, whether RFA may be similarly effective for pain relief for patients with chronic knee, hip, or shoulder pain is unclear.
This report aims to summarize the evidence regarding the clinical effectiveness of, and guidelines with recommendations for, RFA for the treatment of chronic non-cancer knee, hip and shoulder pain.
An information specialist conducted a literature search on key resources including MEDLINE, Embase, the Cochrane Database of Systematic Reviews, the International HTA Database, the websites of Canadian and major international health technology agencies, as well as a focused internet search. The search approach was customized to retrieve a limited set of results, balancing comprehensiveness with relevancy. The search strategy comprised both controlled vocabulary, such as the National Library of Medicine’s MeSH (Medical Subject Headings), and keywords. Search concepts were developed based on the elements of the research questions and selection criteria. The main search concepts were radiofrequency ablation and chronic knee, hip, and shoulder pain. CADTH-developed search filters were applied to limit retrieval to health technology assessments, systematic reviews, meta-analyses, or indirect treatment comparisons, any types of clinical trials or observational studies, and guidelines. The search was completed on August 22, 2023 and limited to English-language documents published since January 1, 2018.
One reviewer screened citations and selected studies. In the first screening level, titles and abstracts were reviewed and potentially relevant articles were retrieved and assessed for inclusion. The final selection of full-text articles was based on the inclusion criteria presented in Table 1.
Selection Criteria.
Articles were excluded if they did not meet the selection criteria outlined in Table 1, they were duplicate publications, or were published before 2018. Systematic reviews in which all relevant studies were captured in other more recent or more comprehensive systematic reviews were excluded. Systematic reviews in which there was partial overlap of relevant studies with 1 or more recent or comprehensive systematic reviews were excluded and the primary study(ies) missing from the more recent systematic review were retained and included in this review, even if published before 2018. Primary studies retrieved by the search were excluded if they were captured in 1 or more included systematic reviews. Guidelines with unclear methodology were also excluded.
The included publications were critically appraised by 1 reviewer using the following tools as a guide: A MeaSurement Tool to Assess systematic Reviews 2 (AMSTAR 2)14 for systematic reviews, the Downs and Black checklist15 for randomized and nonrandomized studies, and the Appraisal of Guidelines for Research and Evaluation (AGREE) II instrument16 for guidelines. Summary scores were not calculated for the included studies; rather, the strengths and limitations of each included publication were described narratively.
A total of 449 citations were identified in the literature search. Following screening of titles and abstracts, 402 citations were excluded and 47 potentially relevant reports from the electronic search were retrieved for full-text review. 18 potentially relevant publications were retrieved from the grey literature search for full-text review. Of these potentially relevant articles, 57 publications were excluded for various reasons. After the assessment of overlap across the SRs meeting the inclusion criteria, 1 unique RCT17 from an SR excluded for partial overlap18 was retrieved. Nine publications met the inclusion criteria and were included in this report. These comprised 4 systematic reviews, 2 primary studies, and 3 evidence-based guidelines. Appendix 1 presents the PRISMA19 flow chart of the study selection.
Two SRs7,20 and 2 primary studies10,17 were included for chronic knee pain, and 2 SRs21,22 were included for chronic hip pain. No evidence was found for chronic shoulder pain. Three guidelines23-25 were included.
Additional references of potential interest are provided in Appendix 7.
Three publications had broader inclusion criteria than the present review.
Fogarty et al. (2022)7 examined the clinical effectiveness of fluoroscopically guided genicular RFA compared to non-surgical interventions including some not relevant to the present review (e.g., other forms of RFA). The 2019 American College of Rheumatology/Arthritis Foundation Guideline for the Management of Osteoarthritis of the Hand, Hip and Knee24 makes recommendations for pharmacologic and nonpharmacologic management of OA, including for the use of RFA plus usual care for knee OA. Kao et al. (2018)22 conducted an SR on the clinical effectiveness of RFA for hip pain. Two of the included studies (2/10) involved patients with postoperative hip pain and patients with cancer and 2/10 studies used pulsed RFA. Only characteristics, results, and recommendations of the subset of relevant publications will be described in this report.
In addition, 1 SR did not identify any relevant studies. Chou et al. (2020)21 evaluated the clinical effectiveness of 10 intervention procedures for 10 pain conditions, including cooled RFA versus usual care, sham, placebo, or no treatment for degenerative hip pain. However, no evidence was found for these comparisons. Due to the limited amount of evidence identified on the use of RFA for hip pain (1 SR with evidence22), 2 included studies in the SR that used pulsed RFA are included and summarized separately throughout this report.
Additional details regarding the characteristics of included publications are provided in Appendix 2.
This review identified 2 SRs for RFA treatment of knee pain, 1 published in 2022,7 and 1 in 2021.20 The databases were searched from inception to October 10, 20207 and November 13, 2019.20 Fogarty et al. (2022)7 contained 5 RCTs across 8 publications, and 1 case series, of which 3 RCTs (3 publications) were relevant to the present review. The results were synthesized narratively. Chen at al. (2021)20 included 7 RCTs and summarized the results via meta-analysis. A table describing the overlap of relevant studies within these 2 SRs is provided in Appendix. 5.
This review also identified 2 primary studies on RFA treatment of chronic knee pain, a triple-blinded RCT published in 202210 and an open-label, nonrandomized controlled trial published in 2011.17
This review identified 2 SRs for RFA treatment of hip pain, 1 published in 202121 and 1 published in 2018.22 The databases were searched from 1990 to April 202121 and from inception to January 20, 2017.22 Chou et al. (2021) found no evidence relevant to this review and Kao et al. (2018)22 included 6 case series or case reports on RFA and 1 nonblinded, uncontrolled, clinical trial and 1 case series using pulsed RFA.
This review identified 3 guidelines: 1 focuses on patients with knee osteoarthritis (OA)23 and 2 are broader but included recommendations for the use of RFA for hip and knee pain.24,25
The National Institute for Health and Care Excellence (NICE) published their guidance in 2023.23 A rapid review was conducted to gather evidence on the efficacy and safety of RFA for the treatment of patients with knee OA. All clinical study types were eligible for inclusion. Ratings of the quality of evidence and strength of the recommendations, and the methods used by the guideline development group to produce the recommendations, are not reported.
The American Society of Pain and Neuroscience (ASPN)25 published their guidelines in 2021. A literature search of 3 databases was conducted to gather evidence on the use of RFA for 7 anatomic targets including the knee and hip joints. Systematic reviews, literature reviews, RCTs, prospective and retrospective observational studies were eligible for inclusion. The US Preventive Services Task Force criteria for quality of evidence and strength of recommendations is used. The quality of evidence is rated on a 5-level scale (I, II-1, II-2, II-3 and III) where I is highest and III is lowest quality evidence. The strength of recommendations is rated from A (highest) to D (lowest), or I (insufficient evidence to make a recommendation).
The American College of Rheumatology (ACR) and the Arthritis Foundation published their guidelines in 2020.24 A systematic search of the literature was conducted to identify evidence on the benefits and harms of available interventions for OA of the hand, hip and knee, including RFA. RCTs and observational studies were eligible for inclusion. The quality of evidence and strength of recommendations was graded using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology: the certainty of the evidence is assessed from very low to high, and the strength of a recommendation for or against an intervention can be weak or strong.
The first authors of the SRs were from the US.7,20 The primary studies were conducted in Thailand10 and Japan.17
The first author of the SR on hip pain22 was from the US.
The SRs included adult patients diagnosed with knee OA. Studies were excluded if patients underwent knee arthroscopy. A total of 392 patients were included in the Fogarty et al. (2022)7 review, while the total number of patients was not reported in Chen et al. (2021).20 No other demographic or clinical information was reported in either SR. The primary studies enrolled 6410 and 3517 patients with knee OA. The mean age of patients in the primary studies was 66.710 and 7717 years, and the majority was female.
A total of 43 adult patients was included in the SR on hip pain: 26 patients received RFA (excluding pulsed RFA) and 17 patients received pulsed RFA.22
RFA (excluding pulsed RFA). Specific age was reported for 3 case reports (mean: 56 years).22 Three publications involved patients with hip pain due to OA.22 One case series involved patients with general chronic hip pain excluding metastasis to hip, a second case series involved chronic hip pain due to avascular necrosis of femoral head, and 1 case report focused on a patient with destructive coxopathy due to repeated radiation.22
Pulsed RFA: Age was not reported. Both studies involved patients with hip OA.22
The target population of the guidelines are patients with osteoarthritic knee pain,23 patients with pain in the knee and hip joints,25 and patients with OA of the knee or hip.24 The intended users are health care providers, but the NICE23 and ACR24 guidelines also refer to patients and caregivers as a potential audience.
The interventions included in the SRs were fluoroscopically guided cooled RFA,7,20 conventional monopolar RFA,7,20 and bipolar RFA.7 Both SRs included medical management, intra-articular hyaluronic acid (IA-HA) injection, and intra-articular steroid (IAS) injection as comparators. Chen et al. (2021)20 included 1 study with sham-RFA as a comparator.
Among the primary studies, interventions varied in target, frequency and method. Both were fluoroscopy guided and performed sensory/motor stimulation for localization.10,17 The RCT did a prognostic nerve block before randomization10 Malaithong et al. (2022) and the nonrandomized controlled trial did a nerve block 1 day before the intervention.17 Malaithong et al. (2022)10 conducted bipolar RFA on 3 genicular nerves simultaneously and Ikeuchi et al. (2011)17 performed 2 RFA treatments 2 weeks apart on the medial retinacular nerve and the infrapatellar branch of the saphenous nerve. The lesions were made at 90° for 180s,10 and 70°C for 90s.17 Comparators were genicular nerve block at 3 target sites, local anesthetic and steroid injection plus sham-RFA,10 and local anesthetic.17
The specific intervention details varied across the 8 included publications within the SR identified for this report.22
RFA (excluding pulsed; 6 studies): A pre-treatment diagnostic nerve block was performed in 3 studies. Fluoroscopy guidance was used in 4 studies, ultrasound guidance was not used, and 2 studies did not report method of guidance. Sensory/motor stimulation was used in 3 studies. Five studies used thermal RFA, at varying temperature and duration: 90°C for 180 seconds (s) per target or 90s per target, 80°C for 120 seconds per target, 75°C to 80°C for 90 seconds per target, and 75°C to 90°C for 90s per target. When reported, a 22-gauge needle was used with a 100 mm electrode and 4 mm, 5 mm, and 10 mm exposed tip.
Pulsed RFA: Two studies used pulsed RFA. Both used fluoroscopic guidance, 42°C and 20 ms generator output of 45 V (1at 120s and 1 at 180s).
The NICE guidelines23 describe the RFA intervention in general terms, including that it can be conducted under fluoroscopic or ultrasound guidance and that several targets have been identified including the genicular nerves. The ACR24 guidelines are similarly general, citing the intervention as “radiofrequency ablation”. The ASPN25 guideline includes a literature review and summary of the procedure techniques for both knee and hip RFA, including the general guidance on options for technique, electrode settings, target sites, and use of preprocedure diagnostic blocks. However, the recommendation statements are general: they specify the target nerves (the genicular nerve or obturator and femoral nerve branches for knee or hip pain, respectively) but do not further specify recommended treatment protocols.
All included SRs and primary studies measured pain via the visual analogue scale (VAS), function via the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the frequency of adverse events (AEs).7,10,17,20 Additional function measures included the Oxford Knee Scale,7 and the patient global impression of improvement Likert scale.10,17
The outcomes from the Kao et al. (2018)22 SR included pain measured via VAS, function measured via the Lower Extremity Functional Scale and the frequency of AEs.
The outcomes considered by the NICE guideline panel23 were pain (VAS, the numeric rating scale), function (WOMAC, global perceived effort scale, timed up and go test and EQ-D5) and safety (pain, infection, numbness, damage to adjacent structures). ASPN25 considered improvement in pain (any scale), function, analgesic use, subsequent need for surgery, health care utilization and return to work. ACR24 considered pain, function (self-reported) and function (performance based).
The SRs had clear research questions, comprehensive literature reviews and study selection in duplicate. This increases the likelihood that relevant studies were not missed. With respect to the analysis, Fogarty et al. (2022)7 extracted data in duplicate, and described the included studies in some detail, but additional patient characteristics would have enhanced interpretation. An important weakness of Chen et al. (2021)20 is the lack of demographic, clinical and other information about the included patients: it’s neither in the publication nor the supplementary information. Therefore, it is difficult to interpret the results and assess the external validity of the findings.
The primary studies10,17 had clearly defined objectives, main outcomes, characteristics of the included patients, and interventions. The presented results were described in the methods, the statistical tests were appropriate, compliance with the intervention was reliable and the main outcome measures were valid and reliable. Malaithong et al. (2022)10 was a blinded (both study subjects and those measuring the main outcomes), randomized trial. There was sufficient power to detect a clinically important effect in VAS at all time points except 10 and 12 months. By contrast, Ikeuchi et al. (2011)17 was an unblinded, nonrandomized trial with insufficient information provided to determine whether the study had sufficient power to detect clinically important differences between the treatment groups (a total of 35 patients were enrolled). Neither study provided sufficient information to assess external validity, or whether confounding was assessed adequately.
Both SRs21,22 had clear research questions containing the components of PICO, had comprehensive literature reviews with searches of at least 4 databases, justified their selection of included study types, conducted study selection in duplicate and reported no conflicts of interest. Neither performed data extraction in duplicate nor provided a list of excluded studies. Kao et al. (201822 provided a satisfactory explanation for, and discussion of, the heterogeneity observed but there were concerns with the risk of bias [RoB]). The method to assess RoB was not reported, but the authors stated there was a large RoB within the included studies due to lack of blinding and small sample sizes which is inherent in the design of included studies (i.e., case series/reports).22
The ACR guideline24 performed well across all AGREEII domains, except applicability, and has strengths that the other 2 guidelines do not. The scope and purpose of the ACR guideline24 is clear, all relevant professional groups and the target population participated in the development group, and the target users are clearly defined. The guideline was developed using rigorous methods for evidence synthesis and recommendations development, and with editorial independence, with the only area of uncertainty being whether external review occurred. The guideline’s weakness relates to its applicability: facilitators and barriers to application are not mentioned, and no advice or tools are provided to enable implementation. Conversely, both NICE23 and ASPN25 did have resources available for implementation (methods for putting evidence into practice,23 best practice summary).25 However, the rigour of development is unclear for both NICE23 and ASPN.25 Systematic methods were used to identify evidence, but the strengths and limitations of the body of evidence and the methods for formulating recommendations are not provided. While ASPN25 did have an explicit link between the evidence and the recommendation, the assigned evidence level of II-1 (defined as evidence from a “well-designed, controlled, nonrandomized clinical trial (p. 2809)”25) did not align with the stated source evidence (uncontrolled studies). NICE23 did not include an explicit link between the evidence and the recommendation. Additional concerns with the NICE guideline are uncertainty around editorial independence (there is no statement on conflict of interest, and it is unclear whether the views of the funding body have influenced the content of the guideline. This leads to difficulty in understanding the rationale for the recommendation statements. The clarity of presentation for all 3 guidelines is good: recommendations are specific and easy to find.
Additional details regarding the strengths and limitations of included publications are provided in Appendix 3.
Appendix 4 presents the main study findings.
Evidence from 2 SRs7,20 and 2 additional primary studies10,17 suggests that the use of RFA for chronic knee pain is clinically effective (Table 8; Table 9; Table 10; Table 11). There is general agreement across studies in favour of RFA versus nonsurgical or sham interventions for nearly all measured outcomes, follow-up time points, and treatment comparisons, with infrequent AEs.
There was some overlap in the primary studies included in the SRs; therefore, to avoid duplication of results, outcome data from an individual primary study are only reported once. The extent of overlap is summarized in Appendix 5. Due to methodologic heterogeneity, neither SR pooled results by meta-analysis.
Pain was measured by VAS at baseline and at 4, 8 and 12 weeks, and at 6 and 12 months (Table 8).
For patients with knee OA, there were inconsistent findings at 4 weeks. Namely, there was no difference between bimodal RFA and sham-RFA groups in mean change from baseline, but a statistically significant between-group difference in mean VAS among those receiving RFA compared to local anesthetic (1 nonrandomized study with 35 patients; 1 RCT with 64 patients).
From 8 weeks to 6 months, VAS measures generally favoured the intervention groups compared to the control groups (2 SRs7,20 and 2 primary studies;10,17 35 to 392 patients):
Function (WOMAC score) was measured at baseline and at 4 weeks, 8 weeks, 12 weeks, and 6 months (Table 9).
Additional measures were summarized in a subset of the included studies:
All studies reported the frequency of adverse events (AE).7,10,17,20 (Table 12).
We identified 2 SRs21,22 that sought evidence regarding the use of RFA, including pulsed RFA, for chronic non-cancer hip pain. Chou et al. (2021)21 did not identify evidence meeting our inclusion criteria. Kao et al. (2018)22 summarized clinical outcomes (pain, function, AE) from a small number of low-quality studies (1 nonrandomized trial, 1 prospective before-and-after study, and 6 uncontrolled case series/reports) involving 43 patients.
The quality and quantity of this identified evidence is therefore insufficient to determine the comparative effectiveness of RFA, including pulsed RFA, for patients with chronic hip pain.
For patients receiving RFA (n = 25):
For patients receiving pulsed RFA (n = 17):
No relevant evidence regarding the use of RFA for chronic shoulder pain was identified; therefore, no summary can be provided.
This review identified 3 guidelines for the use of RFA for the treatment of adults with chronic knee pain (Table 16).
This review identified 1 guideline for the use of RFA for the treatment of chronic hip pain (Table 16).
No relevant guidelines were found regarding the use of RFA for chronic shoulder pain.
There was considerable methodological heterogeneity in the body of evidence gathered for this report. The 2 SRs on knee pain7,20 included studies with 2 to 3 different RFA approaches (cooled, conventional monopolar and bipolar) and between 4 and 5 different comparator treatments. Meta-analysis was therefore not justified, and results were summarized narratively. Similarly, there was inconsistency across the RCTs: 1 RCT compared bipolar RFA to IAS plus sham-RFA, whereas the other RCT compared a two-treatment RFA regimen to local anesthetic. This makes concise interpretation across the body of included evidence challenging.
The generalizability of these results is limited to patients with OA-related knee pain. The patient population from the hip pain-related evidence was more diverse (e.g., 50% of patients experience chronic hip not related to OA), but not sufficiently to be generalizable due to small numbers (n = 26 patients). Further, no demographic, clinical or other confounding variables were summarized in the SRs. Without basic information like the age and sex distribution of the patients, it is difficult to assess the generalizability of the findings to the Canadian context.
The quantity and quality of available evidence on the use of RFA for the treatment of chronic hip pain is low. Two SRs21,22 and 1 guideline25 were identified for hip pain. One well conducted SR did not find any relevant evidence.21 Several reasons for this may exist. First, the authors limited the interventions for this SR to cooled and pulsed RFA; therefore, evidence may have been missed regarding the broader clinical effectiveness of other/all RFA modalities on chronic hip pain. Second, the use of RFA for large joints is relatively new compared to its use for spinal and cranial nerves, so the volume of comparative trials may be low. This is reflected in the SR by Kao et al. (2018),22 which included 6 low-quality observational studies with a total of 26 patients across them.22 Further, the methodological heterogeneity among these studies was substantial so the results could not be pooled to increase the sample size and power to detect differences across the intervention groups.
There is discordance between this review and the ASPN guideline25 regarding the evidence assessment for the use of RFA on hip pain. The ASPN recommendation25 that RFA may be used for the treatment of hip joint pain is informed by 4 nonrandomized studies: 2 retrospective uncontrolled studies, 1 prospective uncontrolled study, and 1 case series. Two of these studies were also captured in the Kao et al. (2018)22 SR (although 1 was not summarized in this review because it included patients with cancer-related pain); 2 were excluded due to study design (i.e., uncontrolled studies). ASPN25 assigned an evidence level of II-1 to this body of evidence which is defined as “well-designed, controlled, nonrandomized clinical trial (p. 2809)”25 despite there not being a controlled trial in the included body of evidence. Due to the discordance between the included evidence and the assigned evidence level, and its unclear interpretation and application to the “best practice summary,” the resulting recommendation should be interpreted and applied with caution.
This report is also limited by the lack of relevant evidence identified on the use of RFA for the treatment of chronic shoulder pain.
This review identified 2 SRs7,20 and 2 primary studies10,17 on the clinical effectiveness of RFA for chronic knee pain; 2 SRs21,22 on the clinical effectiveness of RFA for chronic hip pain; and no evidence on the clinical effectiveness of chronic shoulder pain. Three guidelines were identified: 2 for the use of RFA for knee OA23,24 and 1 for the use of RFA for knee or hip OA.25
Despite the considerable methodological heterogeneity across the included studies due to variation in RFA procedures and choice of comparators, there is consistency in the direction of the effect for pain (VAS) and function (WOMAC) across several time points for the use of RFA on knee OA. This increases the certainty that the use of RFA is clinically effective in reducing pain and improving function among adult patients with chronic OA knee pain. Conversely, there is a lack of certainty around the evidence of effectiveness for the use of RFA on chronic hip pain, despite consistency in the direction of the effect for pain (VAS), due to the small number of low-quality, heterogeneous studies.
Three guidelines23-25 were identified that conditionally recommend the use of RFA for patients with knee OA. These recommendations align with the consistent clinical findings summarized in this review. One guideline25 conditionally recommends using RFA for hip pain following diagnostic blocks. This recommendation is inconsistent with the findings summarized in this review, primarily due to discordance in the interpretation of the quality of evidence, where this review concludes that the small quantity and low-quality evidence available is insufficient to suggest that RFA reduces pain and improves function among patients with chronic non-cancer hip pain.
A research gap exists for good-quality RCTs that evaluate the effectiveness of RFA on chronic hip and shoulder pain. While this review identified an SR focused on the use of RFA for hip pain, that SR identified 1 uncontrolled trial and 5 case series or reports relevant to this review. No RCTs of RFA versus alternative nonsurgical interventions (e.g., routine medical management, corticosteroid joint injection), placebo, or no treatment were identified – either directly through this report’s search or indirectly via included SRs. Further, no evidence was identified on the effectiveness of RFA for chronic shoulder pain going back to January 1, 2018. Decision-makers should consider that this represents a substantial gap in evidence for the use of a nonpharmacological intervention for 2 joint sites affected by OA.1
In addition, the available guidelines lacked recommendations with specificity for best practices for the RFA technique. An opportunity exists to create an evidence-informed resource to support clinicians' ability to optimally perform this procedure. Selection of key procedural parametres such as electrode size, lesioning time, and selection of the target sensory nerves have an impact on the lesion size and the likelihood of denaturing the target nerves.7
Ultrasound-guided RFA is increasingly being explored as an alternative to, or in conjunction with,25 fluoroscopy-guided RFA. As complementary to fluoroscopic guidance, the addition of ultrasound may help with needle placement, improve safety, and decrease the risk of vascular and/or nerve injury, particularly for the challenging anatomy of the hip joint.25 Suggested advantages as an alternative to fluoroscopic guidance include decreased cost, increased availability, and lack of ionizing radiation.7 This review did not identify any studies using ultrasound guidance. Well-designed and adequately powered comparative studies on the effectiveness of ultrasound guidance versus fluoroscopy may expand the opportunities for the application of this technology for knee OA.
The findings of this report suggest that RFA may be an effective treatment option for chronic knee pain due to OA as an alternative to other nonsurgical interventions such as intra-articular injections or oral analgesics in patients with postsurgical pain, those not eligible for surgery or those who are awaiting surgery. In addition, this treatment may provide an alternative nonpharmacologic (e.g., opioid) option for patients with chronic knee OA who are no longer experiencing (or have never experienced) pain relief with existing treatments.
While identified guidelines supported the use of RFA in patients with knee OA, only one25 specified parametres for electrode settings, target nerves, and use of pre-ablative diagnostic blocks and motor testing. The guideline also noted the required knowledge for application of this procedure, so there may be an opportunity for clinician training and knowledge of the anatomic innervation of the knee, the principles surrounding RFA, and experience with fluoroscopy, ultrasound, and the variety of RFA modalities.
American College of Rheumatology
adverse event
American Society for Pain and Neuroscience
intra-articular hyaluronic acid
intra-articular steroid
National Institute for Health and Care Excellence
osteoarthritis
randomized controlled trial
radiofrequency ablation
systematic review
visual analogue scale
Western Ontario and McMaster Universities Osteoarthritis Index
Contributors: Kendra Brett, Elizabeth Carson
Note that this appendix has not been copy-edited.
Selection of Included Studies.
Note that this appendix has not been copy-edited.
Characteristics of Included Systematic Reviews.
Characteristics of Included Primary Clinical Studies.
Characteristics of Included Guidelines.
Note that this appendix has not been copy-edited.
Strengths and Limitations of Systematic Reviews Using AMSTAR 214.
Strengths and Limitations of Clinical Studies Using the Downs and Black Checklist.
Strengths and Limitations of Guidelines Using AGREE II.
Summary of Findings by Outcome for Knee Pain — Pain (VAS).
Summary of Findings by Outcome for Knee Pain — Function (WOMAC).
Summary of Findings by Outcome for Knee Pain — Function (PGI-I).
Summary of Findings by Outcome for Knee Pain — Function (OKS).
Summary of Findings by Outcome for Knee Pain — Adverse events.
Summary of Findings by Outcome for Hip Pain — Pain (VAS).
Summary of Findings by Outcome for Hip Pain — Function (Lower Extremity Function Scale).
Summary of Findings by Outcome for Hip Pain — Adverse events.
Summary of Recommendations in Included Guidelines.
Note that this appendix has not been copy-edited.
Overlap in Relevant Primary Studies Between Included Systematic Reviews.
Note that this appendix has not been copy-edited.
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Copyright © 2023 - Canadian Agency for Drugs and Technologies in Health. Except where otherwise noted, this work is distributed under the terms of a Creative Commons Attribution-NonCommercial- NoDerivatives 4.0 International licence (CC BY-NC-ND).
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