Radiofrequency Procedures for the Treatment of Symptomatic Knee Osteoarthritis: A Systematic Review

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.

Cryoneurolysis for non-cancer knee pain: A scoping review

Background and objective

Cryoneurolysis involves percutaneous insertion of a cryoprobe induced to extremely cold temperatures to disrupt peripheral nerve conduction. The primary objective of this scoping review is to summarize and critically appraise the current evidence for the benefits and safety of cryoneurolysis for non-cancer knee pain. The secondary objective is to describe the variations in cryoneurolysis techniques used.

Methods

MEDLINE, EMBASE, PubMed, Cochrane Library, and Web of Science were searched from their inception to February 2023 for any primary literature investigating the use of cryoneurolysis for non-cancer-related knee pain. Data was extracted for study characteristics, intervention characteristics, and clinical outcomes.

Results

Fourteen studies were identified, including three randomized controlled trials, four retrospective cohort studies, and seven case studies/series. Two studies included knee osteoarthritis patients, three studies included non-specific chronic knee pain patients; and nine studies included pre- or post-total knee arthroplasty patients. Ten studies targeted the infrapatellar branch of the saphenous nerve while the remaining four studies did not report the nerve targeted. Studies consistently demonstrated improvements in pain, function, quality of life, and opioid consumption. Most adverse events were mild and self-limiting. Considerable variations in technique parameters were observed.

Conclusions

Cryoneurolysis is a promising intervention to improve outcomes in non-cancer knee pain populations, particularly in mild-to-moderate knee osteoarthritis and pre-total knee arthroplasty populations. However, cryoneurolysis for knee pain remains largely investigational as more high-quality randomized controlled trials are required to further elucidate efficacy as well as optimal nerve selection and technique.

Cooled radiofrequency ablation versus cryoneurolysis of the genicular nerves for the symptomatic pain management in knee osteoarthritis: a study protocol of a prospective, randomized, single-blinded clinical trial

BACKGROUND

Cooled radiofrequency ablation (CRFA) and cryoneurolysis (CRYO) are two novel methods of genicular neurolysis to relief pain in symptomatic knee osteoarthritis (KOA). In this study, the two methods will be compared, giving us the opportunity to investigate their efficacy, safety and complications.

METHODS

In this prospective randomized trial 70 patients with KOA will be recruited using a diagnostic block of four genicular nerves. Two groups will be created through software randomization: a CRFA group (35 patients) and a CRYO group (35 patients). The target of the interventions will be four genicular nerves; the superior medial, superior lateral, inferior medial, as well as the medial (retinacular) genicular branch from vastus intermedius. The primary outcome of this clinical trial will be the efficacy of CRFA or CRYO at 2-, 4-, 12-and 24-weeks post-intervention using the Numerical Rating Pain Scale (NRPS). The secondary outcomes are the safety of the two techniques, as well as the clinical evaluation using the Knee Injury and Osteoarthritis Outcome Score (KOOS), the Oxford Knee Score (OKS), and the 7-point scale of Patient Global Impression of Change (PGIC).

DISCUSSION

These two novel techniques can block pain transmission through genicular nerves in different ways. In contrast to cryoneurolysis, the CRFA method has been well documented in the past. This is the first clinical trial to compare CRFA vs CRYO and draw conclusions about their safety and efficacy.

TRIAL REGISTRATION

ISRCTN87455770 [ https://doi.org/10.1186/ISRCTN87455770 ]. Registered 29/3/2022, first patient recruited 31/8/2022.

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.

Efficacy of Radiofrequency as Therapy and Diagnostic Support in the Management of Musculoskeletal Pain: A Systematic Review and Meta-Analysis

Radiofrequency (RF) is a minimally invasive procedure used to interrupt or alter nociceptive pathways for treating musculoskeletal pain. It seems a useful tool to relieve chronic pain syndromes, even if, to date, solid evidence is still needed about the effectiveness of this therapy. By this systematic review and meta-analysis, we aimed to evaluate the efficacy of RF in treating musculoskeletal pain. PubMed, Medline, Cochrane, and PEDro databases were searched to identify randomized controlled trials (RCTs) presenting the following: patients with chronic musculoskeletal pain as participants; RF as intervention; placebo, anesthetic injection, corticosteroid injection, prolotherapy, conservative treatment, physiotherapy, and transcutaneous electrical nerve stimulation as comparisons; and pain and functioning as outcomes. Continuous random-effect models with standardized mean difference (SMD) were used to compare the clinical outcomes. Overall, 26 RCTs were eligible and included in the systematic review. All of them analyzed the efficacy of RF in four different regions: cervical and lumbar spine, knee, sacroiliac (SI) joint, shoulder. The outcomes measures were pain, disability, and quality of life. A medium and large effect in favor of the RF treatment group (SMD < 0) was found for the shoulder according to the Visual Analogical Scale and for the SI joint according to the Oswestry Disability Index. A small effect in favor of the RF treatment group (SMD > 0) was found for the spine according to the 36-item Short Form Survey. Non-significant SMD was found for the other outcomes. RF represents a promising therapy for the treatment of chronic musculoskeletal pain, especially when other approaches are ineffective or not practicable. Further studies are warranted to better deepen the effectiveness of RF for pain and joint function for each anatomical region of common application.

Domain Heterogeneity in Radiofrequency Therapies for Pain Relief: A Computational Study with Coupled Models

The objective of the current research work is to study the differences between the predicted ablation volume in homogeneous and heterogeneous models of typical radiofrequency (RF) procedures for pain relief. A three-dimensional computational domain comprising of the realistic anatomy of the target tissue was considered in the present study. A comparative analysis was conducted for three different scenarios: (a) a completely homogeneous domain comprising of only muscle tissue, (b) a heterogeneous domain comprising of nerve and muscle tissues, and (c) a heterogeneous domain comprising of bone, nerve and muscle tissues. Finite-element-based simulations were performed to compute the temperature and electrical field distribution during conventional RF procedures for treating pain, and exemplified here for the continuous case. The predicted results reveal that the consideration of heterogeneity within the computational domain results in distorted electric field distribution and leads to a significant reduction in the attained ablation volume during the continuous RF application for pain relief. The findings of this study could provide first-hand quantitative information to clinical practitioners about the impact of such heterogeneities on the efficacy of RF procedures, thereby assisting them in developing standardized optimal protocols for different cases of interest.