Study protocol for a randomised controlled trial of ultrasound-guided pulsed radiofrequency of the genicular nerves in the treatment of patients with osteoarthritis knee pain

An alternative treatment option in older adults with knee osteoarthritis : Genicular nerve pulsed radiofrequency

Osteoarthritis (OA), including knee OA (KOA), is an important cause of morbidity and disability in older adults. Pain management plays a major role in the treatment of KOA for pain relief and knee function improvement. Ultrasound-guided genicular nerve pulsed radiofrequency therapy is an effective, safe, nonradiative, and easily applicable treatment modality in older adults with KOA. It has a positive effect on geriatric syndromes, especially polypharmacy.

Validation of a new protocol for ultrasound-guided genicular nerve radiofrequency ablation with accurate anatomical targets: cadaveric study

INTRODUCTION

Ultrasound (US)-guided radiofrequency ablation (RFA) of genicular nerves (GNs) is increasingly performed to manage chronic knee pain. The anatomical foundations supporting the choice of original targets for US-guided GN-RFA have been thoroughly improved by recent anatomical studies. Therefore, this study aimed to provide a new protocol with revised anatomical targets for US-guided GN-RFA and to assess their accuracy in a cadaveric model.

MATERIALS AND METHODS

Fourteen fresh-frozen cadaveric knees were used. After a pilot study with 4 knees, five consistent nerves were targeted in the other 10 knees with revised anatomical landmarks: superior medial genicular nerve (SMGN), superior lateral genicular nerve (SLGN), inferior medial genicular nerve (IMGN), recurrent fibular nerve (RFN) and the infrapatellar branch of the saphenous nerve (IPBSN). For each nerve, the lumen of radiofrequency (RF) cannula was prefilled with non-diffusible black paint, and then the cannula was inserted at the target site under US guidance. After US verification of correct placement, the stylet was introduced in the cannula to create a limited black mark on the tissues at the top of the active tip. Anatomical dissection was performed to assess for accuracy.

RESULTS

The proportion of nerves directly found in contact with the black mark was 7/10, 8/10, 10/10 and 9/10 for the SMGN, SLGN, IMGN and RFN, respectively. The proportions of nerve captured by the theoretical largest monopolar RF lesions were 100% for the SMGN, IMGN and RFN, and IPBSN and 95% for SLGN. The mean distances from the center of the black mark to the targeted nerve were 2.1±2.2 mm, 1.0±1.4 mm, 0.75±1.1 mm and 2.4±4.5 mm for the SMGN, SLGN, IMGN and RFN, respectively.

CONCLUSION

US-guided GN-RFA with revised anatomical targets resulted in accurate capture of the five targeted nerves. This protocol provides precise sensory denervation of a larger panel of nerves, targeting those whose constancy regarding anatomical location has been clearly demonstrated. It is expected to improve the clinical outcomes.

Efficacy and Safety of Ultrasound-Guided Radiofrequency Treatment for Chronic Pain in Patients with Knee Osteoarthritis: A Systematic Review and Meta-Analysis

Background

Knee osteoarthritis (KOA) is a common degenerative disease associated with joint dysfunction and pain. Ultrasound-guided radiofrequency (RF) may be a promising therapy in the treatment of chronic pain for KOA patients.

Objective

To evaluate the efficacy and safety of ultrasound-guided RF treatment for chronic pain in patients with KOA.

Design

A systematic review was conducted, and a meta-analysis was carried out when possible. Setting. We examined the studies evaluating the clinical efficiency of ultrasound-guided RF on chronic pain in KOA population.

Method

A systematic review for the efficacy and safety of ultrasound-guided RF treatment for pain management of KOA patients was carried out in PubMed, EMBASE, Cochrane Library, Web of Science, Wanfang Data, and China National Knowledge Infrastructure (CNKI) from the date of inception to February 2020, and a meta-analysis was conducted. The primary outcomes of pain intensity (visual analogue scale or numerical rating scale) and knee function [the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC)] were evaluated from baseline to various follow-up times by random-effects model. Heterogeneity was assessed by I ² statistic and the potential sources of heterogeneity by subgroup and metaregression analyses, respectively.

Results

Eight publications with 256 patients were included in the meta-analysis. RF could relieve pain with -4.196 of pooled mean difference and improve knee function by decreasing 23.155 points in WOMAC. Three patients had ecchymosis, two with hypoesthesia and one with numbness after the procedure, and improved within 6 months. Furthermore, study design and treatment target were the sources of heterogeneity by subgroup and metaregression analyses, accounting for 37% and 74% of variances, respectively. Target of genicular nerve achieved better pain relief than intra-articular or sciatic nerve. Sensitivity analysis showed that removal of any single study was unlikely to overturn the findings. Limitations. There were some limitations in the study. Firstly, the small number of relevant studies limited the confidence level of the meta-analysis. Also, the significant heterogeneity may not be explained due to the limited data. Secondly, the direct comparison of two different guidance methods (ultrasound vs. fluoroscopy) for RF therapy is lacking. In addition, the outcomes were blindly assessed in the meta-analysis from all studies according to evaluation of bias, which could affect the reality of the data. Finally, most of the studies only provided short follow-up times, so we could not analyze the long-term effectiveness of ultrasound-guided RF in the treatment of patients with KOA.

Conclusions

Ultrasonography is an effective, safe, nonradiative, and easily applicable guidance method for RF in pain relief and functional improvement in KOA patients.

Indications of the Neurotomy of Genicular Nerves by Radiofrequency for the Treatment of Knee Osteoarthritis: A Literature Review

Osteoarthritis (OA) is one of the most frequent and incapacitating pathologies today, especially of the knee. Among the possible approaches for knee OA, the neurotomy of the genicular nerves by radiofrequency (RF) has been gaining prominence. However, as this is a relatively new procedure, indications for its implementation are still unclear. The objective of the present review is to identify the main indications of the use of RF for the treatment of knee OA in the medical literature. A review of the literature was performed in January 2018 through a search in the PubMed, ClinicalKey and Google Scholar databases. After reviewing the main articles on the subject, it was concluded that the main indications of the use of RF for the treatment of knee OA were: OA Kellgren-Lawrence grades 3 and 4, with moderate to severe pain and failure of conservative treatment, mainly in elderly people; persistence of pain even after total knee arthroplasty (TKA); patients with an indication for TKA who refuse to undergo surgical treatment.

Alcohol neurolysis of genicular nerve for chronic knee pain

Radiofrequency neurolysis (RFN) of the genicular nerves has recently become accepted as an effective technique to alleviate knee pain particularly in patients with knee osteoarthritis (OA) or postoperative pain. However, genicular nerve RFN can produce high procedure and equipment costs, longer procedural times, procedure-related pain, and failure rate of over 25%. We are presenting two cases of alcohol neurolysis of the genicular nerve using fluoroscopy and ultrasonography in patients with knee OA or persistent postsurgical pain of the knee. Alcohol neurolysis of the genicular nerve with dual imaging modality can be a cheap, safe and effective method in patients with chronic knee pain.

The Efficacy of Ultrasound-Guided Pulsed Radiofrequency of Genicular Nerves in the Treatment of Chronic Knee Pain Due to Severe Degenerative Disease or Previous Total Knee Arthroplasty

Background

Pulsed radiofrequency of genicular nerves in the management of osteoarthritis related chronic knee pain has recently become a promising treatment. Ultrasonography has replaced fluoroscopic guidance in pain medicine. The aim of this study was to investigate the effect of ultrasound-guided genicular pulsed radiofrequency on knee pain and function in patients who had severe knee osteoarthritis or who had previous knee arthroplasty.

Material/Methods

The retrospective study included a total of 23 patients with chronic knee pain, of which 17 patients were included in Group I (non-operated), and 6 patients were included in Group II (post-arthroplasty). Treatment was based on ultrasound-guided pulsed radiofrequency of the superior medial, superior lateral, and inferior medial genicular nerves. The Visual Analog Scale (VAS) and Western Ontario and McMaster Universities Osteoarthritis (WOMAC) scores were assessed before treatment, and at 3 weeks and at 3 months following the procedure.

Results

Pulsed radiofrequency of the genicular nerves significantly reduced perceived pain and disability in the majority of the patients. The proportion of the patients with improvement of ≥50% in pretreatment VAS scores at 3 weeks and 3 months following treatment were 14 out of 17 patients (82%) and 15 out of 17 patients (88%) in Group 1, and 4 out of 6 patients (67%), 4 out of 6 patients (67%) in Group 2, respectively.

Conclusions

Our study results suggest that ultrasound-guided pulsed radiofrequency of genicular nerves is a safe and minimally invasive procedure that significantly alleviates pain and disability in patients with severe degenerative disease or with previous knee arthroplasty.