Does Preoperative Anterior Genicular Nerve Cryoneurolysis Improve Early Outcomes of Primary Total Knee Arthroplasty? A Systematic Review and Meta-Analysis

BACKGROUND: Preoperative cryoneurolysis (CNL) targeting the anterior genicular nerves has gained attention as a minimally invasive technique to reduce pain in patients undergoing primary total knee arthroplasty (TKA). Our objective was to systematically evaluate CNL in TKA, focusing on pain and opioid consumption, patient-reported outcome measures, length of hospital stay (LOS), and adverse events. METHODS: A systematic literature search was conducted in PubMed, Scopus, Web of Science, and Embase for articles published until 2024, without language restrictions. Comparative studies involving adults undergoing TKA, with or without CNL of the genicular nerves, were included. There were two independent reviewers who screened articles and extracted data. Risk of bias was assessed using the Cochrane RoB-2 tool for randomized trials and the Risk Of Bias In Non-randomized Studies - of Interventions for cohort studies. We evaluated the potential conflict of interest (COI) among studies. The Grading of Recommendations, Assessment, Development and Evaluation approach evaluated the certainty of evidence. Meta-analyses employed random-effects models. There were six comparative studies (n = 676 TKAs) that met the inclusion criteria, including two randomized controlled trials. RESULTS: The meta-analysis showed that preoperative CNL substantially reduced acute postoperative pain (Hedge's g = -0.33; 95% confidence interval [CI] -0.49 to -0.17) and opioid consumption (Hedge's g = -0.26; 95% CI -0.46 to -0.07). The LOS was also shorter in the CNL group (mean difference = 0.63; 95% CI 0.20 to 1.05). Functional outcomes at 3 months were similar between groups (Hedge's g = 0.15; 95% CI -0.05 to 0.35). Adverse events were minimal; no difference in complications between groups. Four studies reported COI with CNL manufacturers. CONCLUSIONS: Preoperative CNL offers short-term benefits for TKA patients: reducing pain, opioid use, and LOS without increasing adverse events. However, substantial financial COI in studies raises bias concerns, limiting its routine recommendation. LEVEL OF EVIDENCE: III.