Genicular Nerve Blocks and Radiofrequency Ablation for Knee Osteoarthritis: More Nerves, More Questions

Radiofrequency treatment for chronic knee pain in people with knee osteoarthritis

OBJECTIVES

This is a protocol for a Cochrane Review (intervention). The objectives are as follows: To assess the benefits and harms of radiofrequency treatment of the genicular nerves in people with chronic knee pain due to knee osteoarthritis.

Peripheral Nerve Stimulation for Pain Management: A Survey of Clinical Practice Patterns

BACKGROUND

Clinical interest in and utilization of peripheral nerve stimulation (PNS) for treating chronic pain has significantly increased in recent years owing to its potential for providing analgesia and improved function and quality of life in comparison with pharmacologic treatments. However, the relative infancy of PNS-specific systems and limited clinical practice guidance likely contribute to significant variation in PNS utilization patterns.

OBJECTIVES

We sought to conduct a survey study to characterize PNS-specific clinical practices and propose the next steps in standardizing key practices for PNS utilization.

MATERIALS AND METHODS

A 19-question survey exploring PNS-relevant clinical parameters was disseminated online to pain physicians in practice. Descriptive statistics were used to summarize results.

RESULTS

A total of 94 responses were collected. Regarding patient selection, most practitioners would apply PNS to treat nociceptive pain from major joint osteoarthritis (77.7%) and chronic low back pain (64.9%), but not for axial neck pain (50.0%). In contrast, most would apply PNS to treat neuropathic pain from peripheral neuralgia (94.7%), pericranial neuralgia (77.7%), and cancer-related neuropathic pain (64.9%). In treating complex regional pain syndrome, most practitioners would apply PNS before all other forms of neuraxial neuromodulation (>50% for each form). Similarly, for treating nonsurgical low back pain, most would apply PNS before neuraxial neuromodulation (>50% for each form) but not before radiofrequency ablation (19.2%). Most routinely performed nerve blocks before PNS, mainly to confirm anatomical coverage (84.0%), and regarded a 50% to 75% interquartile range as the minimum analgesic benefit required before proceeding with PNS. Regarding nerve target selection for treating complex regional pain syndrome of the wrist/hand or ankle/foot, or knee osteoarthritis, we observed a very wide variance of PNS target locations and discrete nerves. Regarding "minor" adverse events, most reported not changing PNS utilization on encountering skin/soft tissue reactions (85.1%), minor infections (76.6%), or lead migration/loss of efficacy (50.0%). In comparison, most reported reducing PNS utilization on encountering skin erosion (58.5%), major infections (58.5%), or lead fractures (41.5%).

CONCLUSIONS

There is significant practice variation regarding the utilization of PNS across numerous key clinical considerations. Future research that explores the reasons driving these differences might help optimize patient selection, target selection, periprocedural management, and ultimately outcomes.

Genicular Nerve Block Versus Genicular Nerve Ablation for Knee Osteoarthritis: A Systematic Review of Randomized Controlled Trials and Retrospective Studies

This systematic review aimed to compare the efficacy and safety of genicular nerve ablation and genicular nerve block (GNB) in pain control and functional improvement in knee osteoarthritis (OA) patients using a systematic review of randomized controlled trials (RCTs) and retrospective studies. We searched PubMed, Google Scholar, Cochrane, Science Direct, and Web of Science using specific keywords until April 2023. The primary outcome measures were visual analog scale (VAS) and numerical rating scale (NRS) scores for pain. The secondary outcome measures included functional outcomes assessed by the Western Ontario and McMaster Universities Arthritis Index (WOMAC) score and complications. Four RCTs and two comparative studies met the inclusion criteria. The analysis revealed that both genicular nerve ablation and nerve block effectively reduced pain and improved functionality. Ablation possibly provided more substantial and long-lasting effects than diagnostic blocks. However, the superiority of ablation compared to therapeutic block with steroids is still not conclusive in pain reduction. Functional capacity improvements were comparable between ablation and therapeutic block. Adverse events were minimal and transient.

Cooled versus conventional radiofrequency treatment of the genicular nerves for chronic knee pain: 12-month and cost-effectiveness results from the multicenter COCOGEN trial

BACKGROUND

Radiofrequency (RF) treatment of the genicular nerves reduces chronic knee pain in patients with osteoarthritis (OA) or persistent postsurgical pain (PPSP) after total knee arthroplasty (TKA). The objective of this study is to compare long-term outcomes of cooled and conventional RF and perform an economic evaluation.

METHODS

The COCOGEN trial is a double-blinded, non-inferiority, pilot, randomized controlled trial that compared the effects up to 12 months of cooled and conventional RF in patients with chronic knee pain suffering from OA or PPSP after TKA following a 1:1 randomization rate. Outcomes were knee pain, functionality, quality of life, emotional health, medication use, and adverse events. A trial-based economic evaluation was performed with a 12-month societal perspective. Here, the primary outcome was the incremental costs per quality-adjusted life year (QALY).

RESULTS

41 of the 49 included patients completed the 12-month follow-up. One patient in the PPSP cooled RF group had substantial missing data at 12-month follow-up. The proportion of patients with ≥50% pain reduction at 12 months was 22.2% (4/18) in patients treated with conventional RF versus 22.7% (5/22) in patients treated with cooled RF (p>0.05). There was a statistically significant difference in the mean absolute numerical rating scale at 12 months after cooled RF and conventional RF in patients with PPSP (p=0.02). Differences between other outcomes were not statistically significant. The health economic analysis indicated that cooled RF resulted in lower costs and improved QALYs compared with conventional RF in PPSP but not in OA. There were no serious adverse events.

CONCLUSIONS

Both RF treatments demonstrated in approximately 22% of patients a ≥50% pain reduction at 12 months. In patients with PPSP, contrary to OA, cooled RF seems to be more effective than conventional RF. Additionally, cooled RF has in patients with PPSP, as opposed to OA, greater effectiveness at lower costs compared with conventional RF.

TRIAL REGISTRATION NUMBER

NCT03865849.

9. Chronic knee pain

INTRODUCTION

Chronic knee pain is defined as pain that persists or recurs over 3 months. The most common is degenerative osteoarthritis (OA). This review represents a comprehensive description of the pathology, diagnosis, and treatment of OA of the knee.

METHODS

The literature on the diagnosis and treatment of chronic knee pain was retrieved and summarized. A modified Delphi approach was used to formulate recommendations on interventional treatments.

RESULTS

Patients with knee OA commonly present with insidious, chronic knee pain that gradually worsens. Pain caused by knee OA is predominantly nociceptive pain, with occasional nociplastic and infrequent neuropathic characteristics occurring in a diseased knee. A standard musculoskeletal and neurological examination is required for the diagnosis of knee OA. Although typical clinical OA findings are sufficient for diagnosis, medical imaging may be performed to improve specificity. The differential diagnosis should exclude other causes of knee pain including bone and joint disorders such as rheumatoid arthritis, spondylo- and other arthropathies, and infections. When conservative treatment fails, intra-articular injections of corticosteroids and radiofrequency (conventional and cooled) of the genicular nerves have been shown to be effective. Hyaluronic acid infiltrations are conditionally recommended. Platelet-rich plasma infiltrations, chemical ablation of genicular nerves, and neurostimulation have, at the moment, not enough evidence and can be considered in a study setting. The decision to perform joint-preserving and joint-replacement options should be made multidisciplinary.

CONCLUSIONS

When conservative measures fail to provide satisfactory pain relief, a multidisciplinary approach is recommended including psychological therapy, integrative treatments, and procedural options such as intra-articular injections, radiofrequency ablation, and surgery.

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.

Genicular nerve block for emergency department patient: a successful management of subacute osteoarthritic knee pain

The genicular nerve block (GNB) performed under ultrasound is a common procedure in the perioperative and outpatient setting for the treatment of surgical knee pain and osteoarthritis. It provides motor-sparing analgesia to the knee, making it a potential alternative to other modes of pain management in the emergency department (ED). We present an elderly woman with acute-on-chronic osteoarthritic knee pain which was relieved for a week after a GNB during her ED visit. In patients with knee pain, the ultrasound guided GNB has the potential to provide short-term analgesia for patients with pain refractory to other modes of analgesia. The GNB shows promise as a reliable contribution to a multimodal approach to pain management in the ED setting.

A randomized controlled study of the long-term efficacy of cooled and monopolar radiofrequency ablation for the treatment of chronic pain related to knee osteoarthritis

Background

Chronic knee pain due to osteoarthritis (OA) is expected to become more prevalent. Although conventional therapies may provide relief they are not long-lasting. Persistent pain may lead to total knee replacement, which is not free of adverse outcomes. Monopolar and cooled radiofrequency ablation (RFA) of genicular nerves is an effective option. However, either method may provide distinctive results depending on expected lesion size, a key aspect considering the anatomical variability of knee innervations. This prospective, double-blind, randomized controlled trial evaluated the efficacy and durability of knee RFA using a cooled probe or a monopolar probe of comparable diameter.

Methods

This investigator-initiated, post-market, double-blinded, prospective, randomized controlled trial was approved by the Western IRB. 79 subjects with chronic knee pain due to knee OA were enrolled in multiple locations of a single center. 75 subjects were randomized (1:1) into RFA treatment with either a 4 ​mm/17G cooled active tip (CRFA) or a 10 ​mm/16G monopolar active tip (MRFA) using conventional procedures. Primary endpoint was change in knee pain level (100 ​mm VAS score) from baseline at 24-week post-treatment. Other endpoints include change in functionality, global perceived effect, and frequency of adverse events. Evaluation spanned to 52-week post-treatment. Significance of results (p ​< ​0.05) was calculated using standard statistical analyses.

Results

Both CRFA and MRFA provided significant reduction (41 ​mm and 39 ​mm, respectively) of chronic knee pain at 24-week. At the 52-week visit, reduction in pain level was sustained for CRFA (42 ​mm) but seems to decrease for MRFA (31 ​mm). Improvements in functionality were also significant and sustained with both treatments, although tend to decrease with MRFA at 52-week. Most patients also perceived a very good/good effect of treatments along the duration of the study.

Conclusion

RFA of knee genicular nerves for the treatment of OA chronic pain is effective for 52 weeks post-ablation when using a CRFA (4 ​mm/17G active tip) or MRFA (10 ​mm/16G active tip). The benefits of CRFA seems to be better sustained beyond 24 weeks than the ones of MRFA, although no significant differences were observed at 52 weeks.

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.

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.

Comparison of sensory posterior articular nerves of the knee (SPANK) block versus infiltration between the popliteal artery and the capsule of the knee (IPACK) block when added to adductor canal block for pain control and knee rehabilitation after total knee arthroplasty---A prospective randomised trial

Background and Aims:

Adductor canal block (ACB), though an effective procedure for postoperative analgesia in total knee arthroplasty (TKA), does not provide analgesia to the posterior articular aspect of the knee joint. Infiltration between the popliteal artery and the capsule of the knee (IPACK block) and sensory posterior articular nerves of the knee (SPANK block) are two single injection techniques that have been shown to provide effective analgesia in posterior knee pain. This study aims to compare the effect of IPACK block and SPANK block when combined with ACB for analgesia and postoperative rehabilitation in TKA.

Methods:

A total of 82 patients were randomised into two groups: (1) ACB combined with IPACK, (2) ACB combined with SPANK block. The primary outcome was the pain scores from 6 h to 48 h after surgery and the duration of postoperative analgesia. The secondary outcome measures were 24 h opioid consumption, ambulation parameters like mobilisation ability, quadriceps muscle strength and patient satisfaction score at discharge.

Results:

Numerical rating scale (NRS) scores at rest and on movement, duration of analgesia, total opioid consumption, and patient satisfaction were significantly better (P < 0.05%) in the IPACK group than in the SPANK block. There were no significant differences in the knee rehabilitation parameters between the blocks.

Conclusion:

ACB with IPACK block offers better analgesia, less opioid consumption and better patient satisfaction with comparable knee rehabilitation parameters in the immediate postoperative period after TKA compared to ACB with SPANK block.