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

Can ultrasound-guided radiofrequency ablation of genicular nerves of the knee, be performed without locating corresponding arterial pulsations-a cadaveric study

INTRODUCTION

Given the rising prevalence of knee osteoarthritis, radiofrequency ablation of genicular nerves (RFA) has emerged as a promising treatment option for knee pain. The knee has an extremely complex and variable innervation with nearly 13 genicular nerves described. The frequently ablated genicular nerves are the superomedial (SMGN), the superolateral (SLGN), and the inferomedial (IMGN) genicular nerves. Conventionally, under ultrasound guidance, these nerves are ablated near the corresponding arterial pulsations, but due to the rich vascular anastomosis around the knee joint, identifying the arteries corresponding to these constant genicular nerves can be tedious unless guided by some bony landmarks. In this study, we have evaluated whether it is possible to accurately target these three genicular nerves by just locating bony landmarks under ultrasound in human cadaveric knee specimens.

METHODS

Fifteen formalin-fixed cadaveric knee specimens were studied. SMGN was targeted 1 cm anterior to the adductor tubercle in the axial view. For SLGN, in the coronal view, the junction of the lateral femoral condyle and shaft was identified, and at the same level in the axial view, the crest between the lateral and posterior femoral cortex was targeted. For IMGN in the coronal view, the midpoint between the most prominent part of the medial tibial condyle and the insertion of the deep fibers of the medial collateral ligament was marked. The medial end of the medial tibial cortex was then targeted at the same level in the axial view. The needle was inserted from anterior to posterior, with an in-plane approach for all nerves. Eosin, 2% W/V, in 0.1 ml was injected. Microdissection was done while keeping the needle in situ. Staining of the nerve was considered a positive outcome, and the percentage was calculated. The nerve-to-needle distance was measured, and the mean with an interquartile range was calculated.

RESULT

The accuracies of ultrasound-guided bony landmarks of SMGN, SLGN, and IMGN were 100% in terms of staining, with average nerve-to-needle distances of 1.67, 3.2, and 1.8 mm respectively.

CONCLUSION

It is with 100% accuracy, that we can perform RFA of SMGN, SLGN, and IMGN under ultrasound guidance, by locating the aforementioned bony landmarks.

Comparison of conventional and cooled radiofrequency treatment of the genicular nerves versus sham procedure for patients with chronic knee pain: protocol for a multicentre, double-blind, randomised controlled trial (COGENIUS)

INTRODUCTION

The prevalence of chronic knee pain is increasing. Osteoarthritis (OA) and persistent postsurgical pain (PPSP) are two important causes of knee pain. Chronic knee pain is primarily treated with medications, physiotherapy, life-style changes and intra-articular infiltrations. A radiofrequency treatment (RF) of the genicular nerves is a therapeutical option for refractory knee pain. This study investigates the effectiveness and cost-effectiveness of conventional and cooled RF in patients suffering from chronic, therapy resistant, moderate to severe knee pain due to OA and PPSP.

METHODS AND ANALYSIS

The COGENIUS trial is a double-blinded, randomised controlled trial with 2-year follow-up. Patients and outcome assessors are blinded. Patients will be recruited and treated in Belgium and the Netherlands. All PPSP after a total knee prothesis and OA patients (grades 2-4) will undergo a run-in period of 1-3 months where conservative treatment will be optimised. After the run-in period, 200 patient per group will be randomised to conventional RF, cooled RF or a sham procedure following a 2:2:1 ratio. The analysis will include a comparison of the effectiveness of each RF treatment with the sham procedure and secondarily between conventional and cooled RF. All comparisons will be made for each indication separately. The primary outcome is the Western Ontario and McMaster Universities Osteoarthritis Index score at 6 months. Other outcomes include knee pain, physical functionality, health-related quality of life, emotional health, medication use, healthcare and societal cost and adverse events up to 24 months postintervention.

ETHICS AND DISSEMINATION

Ethics approval was obtained from the Ethics Committee of the University of Antwerp (Number Project ID 3069-Edge 002190-BUN B3002022000025), the Ethics committee of Maastricht University (Number NL80503.068.22-METC22-023) and the Ethics committee of all participating hospitals. Results of the study will be published in international peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT05407610.

Pain management following simultaneous bilateral total knee arthroplasty: genicular nerve blockade versus periarticular injection

The aim of the present study was to investigate whether the analgesic solution prepared for periarticular injection (PAI) could be utilized as a genicular nerve blockade (GNB) agent in bilateral knee arthroplasty, and to assess the pain control efficacy of this approach in comparison with PAI. This was a retrospective cohort in which patients undergoing simultaneous bilateral total knee arthroplasty (TKA) were evaluated. Thirty patients were enrolled. The standard PAI was used for one knee, while the PAI solution was applied in the form of GNB to the other. Visual Analog Scale (VAS) pain scores were measured and recorded separately for each knee, at rest (static) and during exercise (dynamic). Active range of joint motion (JRM) for both knee joints was measured preoperatively, at postoperatively. Compared to the PAI group, the GNB group had lower VAS scores at 2 and 8 hours (p = 0.030 and p < 0.001, respectively). The GNB group also had lower dynamic VAS scores at 2, 8, and 24 hours (p = 0.009, p <0.001 and p<0.001, respectively). Static and dynamic VAS measurements did not demonstrate any differences between groups (GNB vs. PAI) at 48 hours and 30 days (p>0.05). When the reduction in VAS scores was assessed, we found that the decrease in both scores was significantly greater in the PAI group compared to the GNB group (p<0.001, for both). There were no significant differences between the groups with regard to drainage volume, complications and JRM (p>0.05). GNB was found to be more effective for pain control throughout the first postoperative day in patients who underwent simultaneous bilateral TKA.

Comparison of cooled versus conventional radiofrequency treatment of the genicular nerves for chronic knee pain: a multicenter non-inferiority randomized pilot trial (COCOGEN trial)

BACKGROUND

Radiofrequency (RF) treatment of the genicular nerves has the potential to reduce chronic knee pain due to osteoarthritis or persistent postsurgical pain, however, a direct comparison between the two main modalities used, conventional and cooled, is lacking.

METHODS

This double blind, non-inferiority, pilot, randomized controlled trial compared the effects of cooled and conventional RF in chronic knee pain patients suffering from osteoarthritis or persistent postsurgical pain after total knee arthroplasty. Patients were randomized following a 1:1 rate. The primary outcome was the proportion of patients with ≥50% pain reduction at 3 months postintervention. Other outcomes were knee pain, functionality, quality of life, emotional health, and adverse events up to 6 months postintervention. Conventional RF treatment was tested for non-inferiority to cooled in reducing knee pain at 3 months follow-up.

RESULTS

Forty-nine of 70 patients were included, of which 47 completed a 3-month follow-up. The primary outcome was achieved in 4 of 23 patients treated with conventional RF (17%) vs in 8 of 24 with cooled (33%) (p=0,21). Results from the non-inferiority comparison were inconclusive in relation to the non-inferiority margin. There was no statistically significant difference between secondary outcomes. There were no serious adverse events.

CONCLUSIONS

Both conventional and cooled RF treatment reduced pain in the osteoarthritis and persistent postsurgical pain population. This pilot study did not demonstrate statistically significant differences in the proportion of patients experiencing ≥50% pain reduction between techniques. The non-inferiority analysis was inconclusive. These results warrant further research.

TRIAL REGISTRATION NUMBER

NCT03865849.

Ultrasound-guided genicular nerves block vs. local infiltration analgesia for total knee arthroplasty: a randomised controlled non-inferiority trial

Genicular nerves block is a promising technique to treat acute postoperative pain in total knee arthroplasty. Similar to surgeon-administered local infiltration analgesia, it targets sensory branches from the knee capsule, but through a selective ultrasound-guided injection that reduces local anaesthetic dose (150 ml ropivacaine 0.2% with local infiltration analgesia vs. 20 ml with genicular nerves block). This randomised non-inferiority trial compared the analgesic efficacy of genicular nerves block vs. local infiltration analgesia in the first 24 h following total knee arthroplasty. Sixty patients were randomly allocated to receive either ultrasound-guided block of five genicular nerves or local infiltration analgesia. The primary outcome was rest pain numeric rating scale (0-10) at 24 h. Secondary outcomes included pain numeric rating scale (rest and movement) and cumulative opioid consumption during the first 24 h. We analysed 29 patients in the genicular nerves block group and 30 in the local infiltration analgesia group. We found that the median difference (95%CI) in postoperative rest pain at 24 h (non-inferiority criteria, Δ = 1) was -1.0 (-2.0 to 1.0, p < 0.001). Median difference in cumulative opioid consumption was 0.0 mg (-3.0-5.0, p < 0.001) meeting the non-inferiority criteria, Δ = 23 mg. We conclude that genicular nerves block of five nerves provides non-inferior analgesia in the first 24 h following surgery compared with local infiltration analgesia, but with a considerable reduction in the local anaesthetic dose.

Motor-Sparing Neural Ablation with Modified Techniques for Knee Pain: Case Series on Knee Osteoarthritis and Updated Review of the Underlying Anatomy and Available Techniques

Knee osteoarthritis (KOA) is ubiquitous. However, effective pain managements for patients with grades 3 or 4 KOA for whom conservative treatments are unsuccessful, but for whom surgery is not an option, remain lacking. This case series presented two motor-sparing interventional pain treatment modalities for five such patients. Three of the patients with a mean total WOMAC score of 41 underwent thermal radiofrequency (RF) ablation using a modified motor-sparing approach. One-week and four-week post-RF, the total score dropped to 27 (by 34%) and 19 (dropped 53.7%), respectively. Two other similar patients with a mean total WOMAC score 96 underwent chemical neurolysis using a motor-sparing approach with modified landmarks. The WOMAC score dropped to 58.5 (by 39.1%) and 49 (dropped by 49.0%), one-week and four-week postchemical neurolysis, respectively. A narrative review of the currently available approaches is also provided, with the conclusion that neural ablation using the modified landmarks approach may achieve better pain control and preserve the motor functions for patients with severe KOA for whom conservative treatment was unsuccessful and who are not candidates for surgery.

The Effectiveness of Fluoroscopically Guided Genicular Nerve Radiofrequency Ablation for the Treatment of Chronic Knee Pain Due to Osteoarthritis: A Systematic Review

ABSTRACT

The objective was to determine the effectiveness of fluoroscopically guided genicular nerve radiofrequency ablation for painful knee osteoarthritis. Primary outcome measure was improvement in pain after 6 mos. Secondary outcomes included the Oxford Knee Score and Western Ontario and McMaster Universities Osteoarthritis Index. Two reviewers independently assessed publications before October 10, 2020. The Cochrane Risk of Bias Tool and Grades of Recommendation, Assessment, Development, and Evaluation system were used. One hundred ninety-nine publications were screened, and nine were included. Six-month success rates for 50% or greater pain relief after radiofrequency ablation ranged from 49% to 74%. When compared with intra-articular steroid injection, the probability of success was 4.5 times higher for radiofrequency ablation (relative risk = 4.58 [95% confidence interval = 2.61-8.04]). When radiofrequency ablation was compared with hyaluronic acid injection, the probability of treatment success was 1.8 times higher (relative risk = 1.88, 95% confidence interval = 1.38-2.57). The group mean Oxford Knee Score and Western Ontario and McMaster Universities Osteoarthritis Index scores improved in participants receiving genicular radiofrequency ablation compared with intra-articular steroid injection and hyaluronic acid injection. According to Grades of Recommendation, Assessment, Development, and Evaluation, there is moderate-quality evidence that fluoroscopically guided genicular radiofrequency ablation is effective for reducing pain associated with knee osteoarthritis at minimum of 6 mos. Further research is likely to have an important impact on the current understanding of the long-term effectiveness of this treatment.

New ultrasound-guided techniques in chronic pain management: an update

PURPOSE OF REVIEW

The introduction of ultrasound guidance in interventional pain management leads to the development of new interventional pain management techniques. Ultrasound-guided (UG) interventional pain management is rapidly developing and increasingly more commonly used, due to its many advantages over traditional radiologic imaging modalities. This review will summarize recent literature around novel interventional pain techniques with ultrasound guidance published over the last 18 months.

RECENT FINDINGS

Many new interventional pain management methods have been described in the last few years in the literature. The use of ultrasonography in interventional pain management played a crucial role in these developments. This review includes newly described interventional methods in the literature. The review particularly focussed on the methods that are used to treat the pain in the hip, shoulder, knee, and lumbar area. These new techniques hold promise for significant improvements in the efficacy and safety of interventional pain management.

SUMMARY

There have been many innovations in UG interventional procedures, however, some of them require more rigorous validation before their widespread use.

Genicular Nerve Anatomy and Its Implication for New Procedural Approaches for Knee Joint Denervation: A Cadaveric Study

OBJECTIVE

To verify the articular branch contributions in the human knee, delineate their anatomical variance, and outline the limitations of currently applied procedure protocols for denervation of the knee joint.

DESIGN

A detailed anatomical dissection.

SETTING

Cadavers in residence at the Albert Einstein College of Medicine.

SUBJECTS

In total, 24 lower extremity specimens from 14 embalmed cadavers.

METHODS

Human cadaveric dissections were performed on 24 lower extremities from 14 embalmed cadavers.

RESULTS

This cadaveric study has demonstrated that the anterior knee receives sensory innervations from SMGN, SLGN, LRN, NVI, NVL, RFN, and IMGN. The courses of SMGN, SLGN, RFN, and IMGN are similar to recent anatomical studies. However, discrepancies exist in their relative anatomy to bony and radiographic landmarks.

CONCLUSIONS

Genicular denervation using classical anatomical landmarks may not be sufficient to treat the anterior knee joint pain. Our findings illustrate more accurate anatomic landmarks for the three-target paradigm and support additional targets for more complete genicular denervation. This cadaveric study provides robust anatomical findings that can provide a foundation for new anatomical landmarks and targets to improve genicular denervation outcomes.