Background: Osteoarthritis (OA) is a prevalent and disabling joint disorder. This systematic review and meta-analysis assessed the effectiveness and safety of minimally invasive interventions targeting the genicular nerves for knee OA.
Methods: We searched for randomised clinical trials (RCTs) that evaluated the use of minimally invasive interventions targeting the genicular nerves in the main general and clinical trial register databases (MEDLINE, Embase, CENTRAL, ClinicalTrials.Gov and the World Health Organization trials portal), up to May 2023. The primary outcomes were pain, function and serious adverse events. Two reviewers independently selected studies, extracted outcome data, and evaluated the risk of bias using the Cochrane RoB-2 tool. Certainty of the evidence was assessed using the GRADE approach. Data was analysed separately according to the comparator group, with emphasis on sham controlled RCTs. Random effects meta-analyses were used to synthesise the results.
Results: Twenty one trials were included (n=1751 participants), evaluating radiofrequency (RF) interventions, genicular nerve block (GNB) and cryoneurolysis. Sham/placebo was the most common comparator (n=6 trials), followed by intra-articular therapies and physical therapies. All results were based on low to very low certainty of evidence. For pain, the data suggest no difference between radiofrequency and sham at 4 weeks; moderate improvements at 12 weeks (mean difference -1.69, 95% CI -3.14 to -0.24, 5 trials), and no difference at 24 weeks. There was no significant change in function at 4, 12, 24, and 48 weeks compared to sham. Based on data from one trial, the evidence is very uncertain about the effect of GNB compared to placebo on pain intensity and function at 4 weeks, indicating a small effect size for pain (mean difference -1.90, 95% CI -3.33 to -0.47), moderate effect size for function (standardized mean difference -0.60, 95% CI -1.12 to -0.07), and no between-group difference at 12 weeks. The evidence is very uncertain about the effect of cryoneurolysis compared to sham (n=1 trial) on pain intensity and function at 4 weeks, indicating a small effect size, and no between-group difference at 12 weeks. No difference in serious adverse events was found between RF, GNB and cryoneurolysis compared to sham.
Conclusion: Minimally invasive interventions including RF, GNB and cryoneurolysis appear to be safe for the management of knee OA symptoms. Based on low- to very low certainty of evidence, the treatment effects found in this review are uncertain. Further high-quality research is needed to establish their efficacy and long-term safety.