Inferior Medial Genicular Nerves Research Articles

Comparison of the efficacy of genicular nerve phenol neurolysis and radiofrequency ablation for pain management in patients with knee osteoarthritis.

: Genicular nerve neurolysis with phenol and radiofrequency ablation (RFA) are two interventional techniques for treating chronic refractory knee osteoarthritis (KOA) pain. This study aimed to compare the efficacy and adverse effects of both techniques. : Sixty-four patients responding to diagnostic blockade of the superior medial, superior lateral, and inferior medial genicular nerve under ultrasound guidance were randomly divided into two groups: Group P (2 mL phenol for each genicular nerve) and Group R (RFA 80°C for 60 seconds for each genicular nerve). The numeric rating scale (NRS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) were used to evaluate the effectiveness of the interventions. : RFA and phenol neurolysis of the genicular nerves provided effective analgesia within groups at 1 week, 1 month, and 3 months compared to baseline. There was no significant difference between the groups in terms of NRS and WOMAC scores at all measurement times. At the 3rd month follow-up, 50% or more pain relief was observed in 53.1% of patients in Group P and 50% of patients in Group R. The rate of transient paresthesia was 34.4% in Group P and 6.3% in Group R, and this was significantly higher in Group P. : Neurolysis of the genicular nerves with both RFA and phenol is effective in the management of KOA pain. Phenol may be a good alternative to RFA. Further studies are needed on issues such as dose adjustment to prevent transient paresthesia response.

The Role of Genicular Radiofrequency Ablation in the Management of Persistent Pain after Total Knee Arthroplasty.

Persistent pain is one of the most frequent complications following total knee arthroplasty (TKA) and can be devastating for the patient's quality of life. The use of genicular nerve radiofrequency ablation (GNRFA) is prevalent regarding non-surgical treatment of knee osteoarthritis. However, it is controversial when employed for the management of residual pain after TKA. This study aims to evaluate the efficacy of GNRFA for the treatment of post-TKA chronic pain and to assess the potential benefits of its use. Twelve patients sustaining chronic pain after TKA underwent GNRFA treatment. The intervention included the superior medial genicular nerve, the superior lateral genicular nerve and the inferior medial genicular nerve. Visual analog scale (VAS) system was utilized for pain assessment at 1-week, 6-month, and 1-year follow-ups. Patients experiencing chronic knee pain derived from other or unspecified causes were excluded. Mean VAS score before the treatment was 8.3, while it ended up 2.3, 5.7, and 7.9 at the 1-week, 6-month, and 1-year follow-up, respectively. Some patients reported residual pain that they regarded more bearable than before the procedure at the 1-week evaluation, with no significant alterations in the 6-month reassessment. In 2 cases results at the 1-week follow-up were dissatisfying, however, this aided us in distinguishing the cause of the persistent pain. We were not able to conclude that GNRFA used for the treatment of chronic pain after TKA is as efficacious as in knee osteoarthritis pain. However, in some cases, it proved to be beneficial regarding discerning the etiology of the pain.

Radiofrequency Ablation of the Infrapatellar Branch of the Saphenous Nerve for the Treatment of Chronic Anterior Inferomedial Knee Pain.

Genicular nerve radiofrequency ablation (GNRFA) is an effective treatment for chronic knee pain related to osteoarthritis. It is often utilized when conservative management has failed and patients wish to avoid arthroplasty, are poor surgical candidates due to comorbid medical conditions, or in those suffering from persistent pain after arthroplasty. The classic targets for GNRFA include the superior lateral genicular nerve, superior medial genicular nerve, and inferior medial genicular nerve but multiple anatomic studies have demonstrated additional sensory innervation to the knee. In this research article, we propose an image-guided technique that can safely target the infrapatellar branch of the saphenous nerve which also provides sensory innervation to the anterior capsule. The proposed technique includes variations for conventional bipolar radiofrequency ablation, cooled radiofrequency ablation, dual-tined bipolar radiofrequency ablation, and monopolar radiofrequency ablation using a long axis approach. The described technique is based on updated anatomic studies and takes into account safety concerns such as thermal risk to the skin and/or pes anserine tendons and breaching of the synovial cavity. Future clinical research should be performed to confirm the safety and effectiveness of this specific approach.

Genicular Nerve Radiofrequency Ablation for the Treatment of Painful Knee Osteoarthritis: Current Evidence and Future Directions.

Genicular nerve radiofrequency ablation (RFA) is increasingly being performed to treat chronic pain due to knee osteoarthritis (KOA). This narrative review provides a concise summary of the relevant neuroanatomy, randomized controlled trials, appropriate patient selection, and safety relating to genicular RFA. Cadaveric studies demonstrate significant variability in the location of the genicular nerves, which has stimulated debate about the ideal target locations for genicular RFA. Despite this, favorable outcomes have been observed in studies targeting only the superior medial genicular nerve, inferior medial genicular nerve, and superior lateral genicular nerve. Several randomized controlled trials demonstrate superiority of genicular RFA compared with intra-articular steroid, viscosupplementation, and oral analgesics. Genicular RFA of the superior medial genicular nerve, inferior medial genicular nerve, and superior lateral genicular nerve appears to be an effective treatment for painful KOA, but targeting additional sensory nerves may further improve treatment success. Although genicular RFA appears relatively safe on the basis of the available data, additional large-scale studies are needed to provide greater confidence.

Is preoperative genicular radiofrequency ablation effective for reducing pain following total knee arthroplasty? A pilot randomized clinical trial

Background and objectiveAlthough total knee arthroplasty (TKA) is an effective treatment for severe knee osteoarthritis (OA), a subset of patients experience significant postoperative pain and dissatisfaction. Several clinical trials support...

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

IntroductionUltrasound (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...

A Randomized Controlled Trial to Compare Analgesia and Functional Improvement After Continuous Neuroablative and Pulsed Neuromodulative Radiofrequency Treatment of the Genicular Nerves in Patients with Knee Osteoarthritis up to One Year After the Intervention.

To compare the analgesic and functional outcomes of continuous neuroablative radiofrequency (CNARF) and pulsed neuromodulative radiofrequency (PNMRF) treatment of genicular nerves up to 1 year after the intervention and to identify predictors associated with a successful outcome (defined as an at least 50% reduction in the pre-interventional visual analog scale [VAS] rating) after genicular radiofrequency treatment. A prospective randomized controlled trial. The Pain Department of the Jerez de la Frontera University Hospital, Cadíz, Spain, from January 2018 until May 2019. Patients with grade 3-4 gonarthritis suffering from knee pain, with a VAS score ≥5 for >6 months. Eligible participants were randomly assigned to receive either CNARF or PNMRF of the superior medial, superior lateral, and inferior medial genicular nerves. The VAS and Western Ontario and McMaster Universities Osteoarthritis (WOMAC) scores were assessed before and at 1, 6, and 12 months after treatment. Medication use was quantified before and at 6 months after the intervention. Potential characteristics associated with the efficacy of radiofrequency intervention were explored by using multivariable statistical models. A total of 188 participants were included. The magnitude and duration of beneficial effect and reduction in analgesic use were significantly greater in the CNARF group. Success at 6 months after radiofrequency treatment decreased with grade 4 gonarthritis; higher pre-interventional VAS score; and concomitant depression, anxiety disorder, and diabetes mellitus. Therapeutic efficacy and reduction in analgesic consumption were superior after CNARF. Treatment success at 6 months after radiofrequency intervention decreased with more severe gonarthritis; higher pre-interventional pain intensity; and concomitant depression, anxiety disorder, and diabetes mellitus.

Accuracy of fluoroscopic-guided genicular nerve blockade: a need for revisiting anatomical landmarks

Background and objectivesGenicular nerve blockade (GNB) and radiofrequency ablation (RFA) have recently emerged as treatment options for patients with chronic knee pain. However, an increasing number of anatomical studies and...

Genicular Nerve Radiofrequency Ablation for Painful Knee Arthritis: The Why and the How.

Genicular nerve radiofrequency ablation (GNRFA), including conventional, cooled, and pulsed techniques, has been used in the management of symptomatic knee osteoarthritis (OA). This new and innovative treatment option has the capacity to decrease pain and improve function and quality of life in certain patients. GNRFA is reserved for patients with symptomatic knee OA who have had failure of conservative treatment and have had failure of or are poor candidates for surgery. GNRFA has been shown to consistently provide short-term (3 to 6-month), and sometimes longer, pain relief in patients. GNRFA has been demonstrated to be safe to administer repeatedly in patients who respond well to this minimally invasive procedure. GNRFA is a 2-step procedure. First, patients are given a diagnostic block under fluoroscopy or ultrasound guidance. Specifically, 1 mL of lidocaine is injected using a 20-gauge, 3.5-in (8.9-cm) spinal needle around the superior lateral, superior medial, and inferior medial genicular nerve branches. The diagnostic block is extra-articular. If the patient reports a ≥50% reduction in baseline pain for a minimum of 24 hours following the injection, then the patient is a candidate for genicular ablation. The osseous landmarks for the diagnostic block are exactly the same as for the ablation procedure. Both procedures are well tolerated in the office setting under local skin anesthesia or can be done in the operating room under conscious sedation using a low-dose sedative such as midazolam for anxious patients. General anesthesia is not required for GNRFA. This procedure is most commonly performed by interventional pain specialists but may also be performed by any physician with appropriate training. In some jurisdictions, physician assistants and nurse practitioners may perform this procedure subject to their supervision requirements. Conservative treatment for symptomatic knee OA includes weight loss management, physical and aquatic therapy, bracing, lateral wedge insoles, transcutaneous nerve stimulation, nonsteroidal anti-inflammatory drugs in combination with a proton pump inhibitor, autologous blood-based therapies, and cortisone and hyaluronic acid injections1,2. Surgical treatment for symptomatic knee OA includes knee arthroscopy, high tibial osteotomy, total knee replacement, and unicompartmental knee replacement in patients without lateral compartment disease2. It should be noted that there is some evidence suggesting that steroid injection, viscosupplements, and arthroscopy are not effective for the management of knee OA. Thermal GNRFA differs from all other treatment alternatives because this procedure causes denaturing of the 3 sensory nerves primarily responsible for transmitting knee pain from an arthritic joint to the central nervous system. In this procedure, heating occurs from an intense alternating electrical field at the tip of the cannula, which produces sufficient heat to denature the proteins in the target tissue. The accepted heating parameters for this procedure are 70° to 80°C for 60 or 90 seconds. A commonly raised question is whether this procedure precipitates a Charcot-type joint. The Charcot joint involves much more than reduced innervation; it occurs in the context of chronically compromised vascularity and altered soft-tissue characteristics as well as peripheral neuropathy. Moreover, a Charcot-type joint does not develop because the deafferentation of the weight-bearing joint is partial3. To our knowledge, no Charcot-type joints have been reported after this procedure. Conversely, data from an animal study have shown that selective joint denervation may lead to the progression of knee OA4. The ablation procedure is done outside the knee joint, unlike alternatives such as intra-articular therapies and surgery. The effectiveness of nonsurgical knee OA interventions in alleviating pain and improving joint function is generally inadequate1. However, GNRFA appears to be an emerging alternative for patients who have had failure of conservative and surgical treatments. It is not uncommon in our clinical practice for patients to achieve adequate pain control following ablation for up to 1 year. GNRFA provides temporary relief from symptomatic knee OA because it does not eliminate the potential for peripheral nerve regrowth and regeneration, and thus pain, to return.

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.

BackgroundPulsed 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/MethodsThe 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.ResultsPulsed 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.ConclusionsOur 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.

03:18 PM Abstract No. 298 Safety and efficacy of image-guided radiofrequency ablation of the genicular nerve for pain management in patients with moderate to severe osteoarthritis of the knee: an initial single-institution experience

To analyze the safety and efficacy of image-guided genicular nerve radiofrequency ablation (RFA) for the treatment of pain in non-surgical candidates with moderate to severe knee osteoarthritis (OA). In an IRB-approved prospective study, consecutive patients with pain from moderate to severe knee OA refractory to anti-inflammatory analgesia and multiple intraarticular lidocaine-steroid injections who underwent radiofrequency ablation of genicular nerves were included. All patients initially underwent anesthetic blocks of the superior medial and lateral and inferior medial genicular nerve branches and experienced great short-term pain relief of >6 points out a 10 scale. Radiofrequency ablation of the same nerve branches were performed 1-2 weeks after nerve block. Follow up at 1 month after the procedure was done to asses for any procedure related complications such as bleeding or infection. Efficacy of the treatment was evaluated using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) to assess overall symptoms, stiffness, pain, and functional daily living pre block/ablation and at 3 months post treatment. A total of ten knees were treated in 8 patients. The average age of the patients was 70.9 years. Mean follow-up time was 3.5 months. No procedure related complication was identified. The mean total WOMAC score (out of 100) improved significantly from baseline score of 47 to 65.9 at 3 months post treatment (p=0.019). Subanalysis of the overall symptoms component of the WOMAC questionnaire demonstrated significant decrease in mean overall symptoms score from 11.4 to 7.3 (p=0.046). Mean stiffness score decreased from 6.2 to 3.5 (p=0.003) and mean pain score decreased from 22.5 to 13.3 (p=0.026). There was also significant improvement in the functional daily living limitations with mean baseline score of 30.2 and 3 month post therapy score of 20.3 (p=0.037). Imaged-guided radiofrequency ablation of genicular nerves is a safe treatment option with good short-term outcome in patients that do not qualify for TKA because of comorbidities with moderate to severe OA of the knee refractory to conservation treatments.

Anatomical Study of the Innervation of Anterior Knee Joint Capsule: Implication for Image-Guided Intervention.

The knee joint is the most common site of osteoarthritis. While joint replacement is considered an ultimate solution, radiofrequency denervation may be contemplated in some cases. Radiofrequency ablation requires precise localization of the articular branches innervating the joint capsule. The objective of this cadaveric study was to determine the source, course, relationships, and frequency of articular branches innervating the anterior knee joint capsule. Fifteen knees were meticulously dissected. The number and origin of the articular branches were recorded, and their distribution defined by quadrants. Their relationships to anatomical landmarks were identified. The articular branches terminated in 1 of the 4 quadrants with minimal overlap. In all specimens, the superolateral quadrant was innervated by the nerve to vastus lateralis, nerve to vastus intermedius, superior lateral genicular and common fibular nerves; inferolateral by the inferior lateral genicular and recurrent fibular nerves; superomedial by the nerve to vastus medialis, nerve to vastus intermedius and superior medial genicular nerve; and inferomedial by the inferior medial genicular nerve. In 3 specimens, the inferomedial quadrant also received innervation from the infrapatellar branch of saphenous nerve. All articular branches except the nerves to vastus lateralis and medialis course at the periosteal level. The frequency map of the articular branches provides an anatomical basis for the development of new clinical protocols for knee radiofrequency denervation and perioperative pain management.

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.

Radiofrequency ablation of genicular nerves has proved to be successful in relieving pain and incapacity caused by osteoarthritis of the knee. However, long-term efficacy of such a treatment remains to be assessed. The current study aimed to reproduce radiofrequency neurotomy of genicular nerves to manage gonarthrosis pain and disability and establish therapeutic response until 1 year after intervention. This single-center, prospective, observational, noncontrolled, longitudinal study included patients with grade 3 to 4 gonarthrosis suffering from intractable knee pain, scoring 5 or more on the visual analog scale (VAS) during >6 months. Therapy was based on ultrasound guided radiofrequency neurotomy of the superior medial, superior lateral and inferior medial genicular nerves. Visual analog scale and Western Ontario and McMaster Universities Osteoarthritis scores were assessed before therapy and at 1, 6, and 12 months following treatment. Radiofrequency neurotomy of genicular nerves significantly reduced perceived pain (VAS) and disability (Western Ontario and McMaster Universities Osteoarthritis) in the majority of participants, without untoward events. The proportion of participants with improvement of 50% or greater in pretreatment VAS scores at 1, 6, and 12 months following intervention were 22/25 (88%), 16/25 (64%) and 8/25 (32%), respectively. Ultrasound-guided radiofrequency neurotomy of genicular nerves alleviates intractable pain and disability in the majority of patients with advanced osteoarthritis of the knee. Such a treatment is safe and minimally invasive and can be performed in an outpatient setting. The beneficial effect of treatment started to decline after 6 months, but even 1 year after the intervention, 32% of patients reported 50% improvement or greater in pretreatment VAS scores.

Accuracy of Ultrasound-Guided Genicular Nerve Block: A Cadaveric Study

Background: Genicular nerve block has recently emerged as a novel alternative treatment in chronic knee pain. The needle placement for genicular nerve injection is made under fluoroscopic guidance with reference to bony landmarks. Objective: To investigate the anatomic landmarks for medial genicular nerve branches and to determine the accuracy of ultrasound-guided genicular nerve block in a cadaveric model. Study Design: Cadaveric accuracy study. Setting: University hospital anatomy laboratory. Methods: Ten cadaveric knee specimens without surgery or major procedures were used in the study. The anatomic location of the superior medial genicular nerve (SMGN) and the inferior medial genicular nerve (IMGN) was examined using 4 knee dissections. The determined anatomical sites of the genicular nerves in the remaining 6 knee specimens were injected with 0.5 mL red ink under ultrasound guidance. The knee specimens were subsequently dissected to assess for accuracy. If the nerve was dyed with red ink, it was considered accurate placement. All other locations were considered inaccurate. Results: The course of the SMGN is that it curves around the femur shaft and passes between the adductor magnus tendon and the femoral medial epicondyle, then descends approximately one cm anterior to the adductor tubercle. The IMGN is situated horizontally around the tibial medial epicondyle and passes beneath the medial collateral ligament at the midpoint between the tibial medial epicondyle and the tibial insertion of the medial collateral ligament. The adductor tubercle for the SMGN and the medial collateral ligament for the IMGN were determined as anatomic landmarks for ultrasound. The bony cortex one cm anterior to the peak of the adductor tubercle and the bony cortex at the midpoint between the peak of the tibial medial epicondyle and the initial fibers inserting on the tibia of the medial collateral ligament were the target points for the injections of SMGN and IMGN, respectively. In the cadaver dissections both genicular nerves were seen to be dyed with red ink in all the injections of the 6 knees. Limitations: The small number of cadavers might have led to some anatomic variations of genicular nerves being overlooked. Conclusions: The result of this cadaveric study suggests that ultrasound-guided medial genicular nerve branch block can be performed accurately using the above-stated anatomic landmarks. Key words: Knee pain, genicular nerve, nerve block, osteoarthritis, ultrasonography, cadaver study, injection, accuracy