The Success of Treatment for Osteoarthritis with a Genicular Nerve Block is Associated with Patients’ Body Mass Index

Background: While the mainstay of treatment for severe osteoarthritis of the knee has been total knee arthroplasty, a prognostic genicular nerve block (GNB) followed by cooled radiofrequency ablation (CRFA) has been shown to provide long term relief of osteoarthritic knee pain and its disability. The goal of this study is to determine if there is a difference in the demographic makeup of those who had a successful prognostic genicular nerve block compared to those who did not. Methods: A retrospective chart review of 224 genicular nerve blocks was completed. The nerve block was considered successful if the patient reported a 50% or greater pain reduction for a week or more at follow up. Demographic cohorts that were compared include sex, age, race, and BMI. Results: Those who were categorized as non-obese, 36 out of 69 (52.2%) had unsuccessful blocks while 33 out of 69 (47.8%) in this BMI category had successful blocks. Of those who were categorized as obese, 25 out of 75 (33.3%) had unsuccessful blocks while 50 out of 75 (66.7%) in this BMI category had successful blocks. Of those who were deemed morbidly obese, 22 out of 75 (29.3%) had unsuccessful blocks while 53 out of 75 (70.7%) in this BMI category had successful blocks. These results were found to be statistically significant with a p-value of .011. Furthermore, GNB success was not found to be significantly impacted by patient age, race, or gender. Conclusions: These findings demonstrate the utility of prognostic genicular nerve blocks in all patients with osteoarthritis of the knee, but, in particular, the obese patient, who experiences a greater chance of pain relief on average.