Genicular nerve chemical neurolysis (GChN) may reduce chronic knee pain in patients with complicating factors associated with poor pain relief outcomes, according to findings from a retrospective, observational cohort study published in Pain Medicine.
Researchers used electronic medical records to identify 85 patients who underwent GChN for chronic, refractory knee pain between 2014 and 2020 and had at least 3 months elapsed since their procedure. The patients had a mean age of 70.1 (SD, 10.5) years; a mean BMI of 31.8 ± 9.0 kg/m2; 74.2% were women; 56.0% had a history of pain lasting more than 3 years; 64.7% had a history of genicular nerve radiofrequency ablation (GRFA) failure; and 21.2% a history of total knee arthroplasty (TKA).
The patients were contacted by telephone and interviewed about opioid analgesic use, pain outcomes using the Numeric Rating Scale (NRS), and overall pain improvement using the Patient Global Impression of Change (PGIC) assessment.
At follow up, an average of 9.9±6.1 months after GChN, 43.5% of patients reported a 50% or greater sustained reduction in pain (95% CI, 33.5-54.1). In addition, 45.9% reported on the PGIC assessment that they were “very much improved” or “much improved” (95% CI, 35.5-56.7).
At baseline, 47.1% of patients reported taking opioids and at follow-up, the percentage decreased to 35.3%. Moreover, patients who did not use opioids at baseline were less likely to use opioids at follow-up (odds ratio [OR], 0.09; 95% CI, 0.01-0.63; P =.004).
No significant group effects were observed for pain reduction or PGIC outcomes, indicating that patients who were refractory to GRFA or TKA had similar positive effects from GChN as patients who were not refractory to treatments.
In the logistic regression analyses, the only significant predictor for outcomes was that opioid use at baseline predicted opioid use at follow-up (OR, 231.38; 95% CI, 16.55-3235.13; P <.001).
Limitations of the study included a lack of data on functional improvements in patients and relying on patient report, which may be subject to recall bias.
“The present data indicate that GChN may provide a robust and durable treatment effect, as measured by pain reduction, patient global impression of change, and opioid analgesic cessation in a subset of individuals, even when including patients with complicating factors traditionally associated with poor treatment outcomes such as high BMI and pain refractory to GRFA and/or following TKA,” the authors noted. “No specific demographic or clinical factors that we evaluated suggest that GChN should be withheld due to a lesser likelihood of treatment effect in any subgroup. A prospective, controlled trial is warranted,” they concluded.
Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.
Shaikh W, Miller S, McCormick ZL, Patel PM, Termoto M, Walega DR. Chemical neurolysis of the genicular nerves for chronic refractory knee pain: an observational cohort study. Pain Med. Published online February 21, 2023. doi:10.1093/pm/pnad022