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

Targeting the Infrapatellar Branch of the Saphenous Nerve for Pain Relief in Patients With Acute or Chronic Knee Pain: A Systematic Review of Randomized Controlled Trials and Cohort Studies

Blocking the infrapatellar branch of the saphenous nerve (IPBSN) can provide analgesic benefits for patients with postoperative acute pain or chronic pain, with minimal adverse effects. To evaluate the analgesic efficacy and potential adverse events associated with IPBSN block in patients suffering from acute or chronic knee pain. We conducted a systematic review across PubMed, Cochrane, Web of Science, and Embase to identify all relevant randomized controlled trials (RCTs) and cohort studies according to predefined selection criteria. The study quality of the RCTs was evaluated using the Cochrane risk of bias assessment tool, while cohort studies were assessed using the ROBINS-I risk of bias tool. The primary outcomes measured were pain intensity and opioid consumption following the nerve block. A total of eight studies were included in this systematic review, encompassing 613 subjects with 276 participants in the control group and 337 participants in the IPBSN block group. The level of evidence was rated high for the RCTs and moderate for the cohort studies. The nerve block was administrated either through the injection of local anesthetic or percutaneous cryoneurolysis targeting the IPBSN. The results indicated that the IPBSN block significantly improved pain relief and reduced opioid consumption in patients with acute postoperative or chronic pain, with no significant difference in the rate of adverse events relating to the procedures or device. The IPBSN block holds promise for improving pain relief and reducing opioid consumption. However, further well-designed randomized controlled trials are needed to confirm these results.

Advanced three-dimensional anatomical mapping of saphenous and inferior medial genicular nerve branching: enhancing precision in knee joint denervation

BACKGROUND

Radiofrequency ablation is a common non-opioid treatment to manage chronic knee pain. The inferior medial genicular nerve is conventionally targeted. It has been suggested that the infrapatellar branch (saphenous nerve) should also be targeted. There is controversy regarding the contribution of the infrapatellar branch to the innervation of the knee joint capsule.

OBJECTIVE

(1) Identify the frequency of the branching pattern(s) of the infrapatellar branch in three-dimensional (3D); (2) Assess spatial relationships of branches of infrapatellar branch to the inferior medial genicular nerve; (3) Determine if capturing infrapatellar branch could result in additional benefit to the existing protocol.

DESIGN

Anatomical study.

METHODS

The infrapatellar branch and inferior medial genicular nerve were serially dissected, digitized, and modelled in 3D in 7 specimens (mean age 91.3 ± 6.5; 2F/5M) and their relationship documented. The spatial relationship of the nerves was used to assess the anatomical efficacy of including the infrapatellar branch in the protocol.

RESULTS

The infrapatellar branch is most frequently a cutaneous nerve. This nerve was variable and found to be unbranched or have 2-3 branches and in all specimens was located superficial to the branches of inferior medial genicular nerve. When the infrapatellar branch (1) coursed more distally, the strip lesion would not capture the infrapatellar branch but would capture inferior medial genicular nerve consistently; (2) overlapped with the inferior medial genicular nerve, the strip lesion would capture both nerves.

CONCLUSIONS

Proposed protocol targeting the infrapatellar branch is likely to capture the inferior medial genicular consistently regardless of the anatomical variation of the infrapatellar branch.

Genicular nerve radiofrequency ablation practice patterns: A survey study of the International Pain and Spine Interventional Society

Introduction

Chronic knee pain often results from degenerative conditions such as knee osteoarthritis (OA) and can worsen after surgical interventions like total knee arthroplasty (TKA). Knee OA affects approximately 86 million individuals globally, leading to decreased function, mobility limitations, and disability. While TKA is a common surgical treatment for refractory knee OA, though up to 20 % of patients experience chronic post-operative knee pain worse than their pre-operative pain. Genicular nerve radiofrequency ablation (GnRFA) has emerged as a promising intervention for knee OA pain unresponsive to conservative management and for chronic post-TKA pain. GnRFA is an evidence-based technique supported by multiple prospective cohort studies and randomized controlled trials (RCTs). However, practice patterns and GnRFA techniques vary, and no peer-reviewed publication has yet quantified these variations in real-world clinical practice.

Objective

This study aims to understand the practice patterns of interventional pain physicians regarding patient selection, use of prognostic blocks, imaging, nerve targets, GnRFA types, and GnRFA techniques in treating knee pain secondary to OA or persistent post-TKA pain.

Methods

An anonymous 29-question survey was distributed via electronic mail to members of the International Pain and Spine Intervention Society (IPSIS) from January 16, 2024, to February 29, 2024. The survey assessed practice patterns related to patient selection, prognostic block use, and GnRFA techniques. Data were collected and stored using REDCap software, with descriptive statistics calculated.

Results

A total of 150 completed surveys were analyzed, representing a completion rate of 2.0 % of surveys sent, 3.5 % of emails opened, and 56.8 % of those who clicked on the survey link. Respondents generally use common selection protocols regarding OA grade (Kelgren-Lawrence 3 and 4), duration of failed conservative care (3-6 months), a single anesthetic block paradigm, and use of fluoroscopic guidance for the GnRFA procedure. More variability was reported between respondents regarding the volume of anesthetic used during prognostic blocks, the threshold to consider a prognostic block "positive," the technology used, and nerves targeted during the GnRFA procedure.

Conclusion

The study provides valuable insights into the current practice patterns of GnRFA among interventional pain physicians. While there is consensus on some aspects of patient selection and procedural techniques, significant variability exists in prognostic block protocols and nerve targets for GnRFA. These findings highlight the need for further research to explore the long-term efficacy and safety of GnRFA and to standardize techniques and protocols across different practice settings, ultimately improving patient outcomes and quality of life. The low response rate may limit generalizability, and the survey did not include data on active tip sizes used for ablation or whether other procedures should be exhausted before resorting to GnRFA. Additionally, a survey to IPSIS membership only may not fully represent a diverse cohort of pain management specialists, potentially introducing sampling bias. Future studies should include members from a broader range of professional organizations to enhance representativeness.

Genicular nerve radiofrequency ablation for the treatment of chronic knee joint pain: a real-world cohort study with evaluation of prognostic factors

BACKGROUND

Genicular nerve radiofrequency ablation (GNRFA) is an effective treatment for chronic knee pain. However, there has been minimal investigation of real-world, long-term outcomes and factors that predict treatment success after GNRFA.

OBJECTIVES

To evaluate the effectiveness of GNRFA for chronic knee pain in a real-world population and identify predictive factors.

METHODS

Consecutive patients who underwent GNRFA at a tertiary academic center were identified. Demographic, clinical, and procedural characteristics were collected from the medical record. Outcome data were numeric rating scale (NRS) pain reduction and Patient Global Impression of Change (PGIC). Data were collected by standardized telephone survey. Predictors of success were evaluated with logistic and Poisson regression analyses.

RESULTS

Of the 226 total patients identified, 134 (65.6 ± 12.7; 59.7% female) were successfully contacted and analyzed, with a mean follow-up time of 23.3 ± 11.0 months. Of those, 47.8% (n = 64; 95% CI: 39.5%-56.2%) and 61.2% (n = 82; 95% CI: 52.7%-69.0%) reported ≥50% NRS score reduction and ≥2-point NRS score reduction, respectively, and 59.0% (n = 79; 95% CI: 50.5%-66.9%) reported "much improved" on the PGIC questionnaire. Factors associated with a greater likelihood of treatment success (P < .05) were higher Kellgren-Lawrence osteoarthritis grade (2-4 vs 0-1); no baseline opioid, antidepressant, or anxiolytic medication use; and >3 nerves targeted.

CONCLUSION

In this real-world cohort, approximately half of the participants experienced clinically meaningful improvements in knee pain after GNRFA at an average follow-up time of nearly 2 years. Factors associated with higher likelihood of treatment success were more advanced osteoarthritis (Kellgren-Lawrence Grade 2-4); no opioid, antidepressant, or anxiolytic medication use; and >3 nerves targeted.

Anterior knee pain and sit-up tests predicts patients' satisfaction and improvement in quality of life after anterior stabilized total knee replacement without patellar resurfacing

PURPOSE

The purpose of this study was to assess patient satisfaction and identify risk factors for dissatisfaction after anterior stabilised conventional total knee arthroplasty (TKA) without patellar resurfacing, using the Goodman score.

METHODS

We conducted a cross-sectional study using data from our institutional database from 1 January 2018 to 1 March 2021. Patients who underwent TKA with the Vanguard® Cruciate Retaining Anterior Stabilized Knee System (Zimmer Biomet, Warsaw, Indiana, USA) without patellar replacement were included. Patients with other bearing surfaces (posterior stabilised or medial congruent) or diagnosed with infection or instability were excluded. Patients' reported outcomes, body mass index (BMI), passive range of motion, the timed up-and-go test, sit-up test, and algometry were assessed. Patients were also asked if they had anterior knee pain. Satisfaction was assessed using the Goodman scale, and logistic multivariate regression was used to identify variables associated with dissatisfaction and perceived improvement in quality of life.

RESULTS

A total of 131 TKA patients were included in the study. The median satisfaction score was 100 (interquartile range [IQR], 87.5 to 100), with the 75-point threshold at the 90th percentile according to Section A of Goodman. Section B of Goodman showed that 113 TKA patients (86.26%) reported "great improvement" or "more than I ever dreamed." Multivariate logistic regression revealed that anterior knee pain (OR 5.16, 95% CI 1.24 to 21.39), the sit-up test (OR 0.63, 95% CI 0.49 to 0.81), and BMI (OR 0.84, 95% CI 0.70 to 0.99) were significantly associated with patient dissatisfaction and a worse perceived improvement in quality of life. The receiver operating characteristics curve for the models had areas under the curve of 0.83 (95% CI 0.69 to 0.97) and 0.82 (95% CI 0.70 to 0.94), respectively.

CONCLUSION

Anterior stabilised TKA without patellar resurfacing can achieve 90% satisfaction and 86% improvement in quality of life. To improve these results, it is essential to prevent and treat anterior knee pain and enhance quadriceps strength.

LEVEL OF EVIDENCE

Level III (retrospective cohort study).