Intraarticular STP Radiofrequency for Painful Osteoarthritis in the Knee: A Retrospective Single Center Analysis

Abstract

Objective: Osteoarthritis (OA) is the most common cause of chronic knee pain, often a debilitating condition that can cause a significant reduction in functional capacity. Radiofrequency is a form of neuromodulation that modulates pain signal transmission and has become progressively more common as a treatment for knee pain. This retrospective study aims to evaluate the efficacy of intraarticular radiofrequency in patients with chronic knee OA pain.

Materials and methods: In this retrospective study, we included 129 patients undergoing intraarticular pulsed radiofrequency using the Poisson curve for energy distribution (Sluijter-Teixeira Poisson radiofrequency) (STP) from March 2018 to November 2019. Knee osteoarthritis severity was assessed prior to the procedure using the Lequesne Index, classifying patients into six groups based on level of severity. Pain intensity was assessed through a 10-cm visual analog scale (VAS), and level of patient satisfaction was assessed through a questionnaire.

Results: In the sample, pain reduction as measured by VAS compared to baseline prior to the procedure was statistically significant immediately following the procedure, at 30 days and at 90 days (p<0.001); this difference was less significant at 180 days (p<0.005). Efficacy in patients with moderate to severe disability was considerably greater than in patients with very severe to extremely severe disability. 57.36% reported that they were very satisfied, 29.46% satisfied, 9.3% neither satisfied nor dissatisfied, 2.33% dissatisfied, and 1.55% very dissatisfied.

Conclusion: Our results suggest that STP radiofrequency may be a safe and effective procedure for knee OA, able to significantly reduce VAS scores at 1 month and 3 months compared to baseline. Based on our results, a key factor to consider when treating knee OA with STP radiofrequency is that it is more effective among patients with a lower level of disability. Due to the retrospective observational study design, prospective longitudinal investigation is required to further support the recommendation of STP radiofrequency for knee OA.

Keywords: chronic pain; knee; knee joint; osteoarthritis; pulsed radiofrequency treatment.

Figure 1

Patient distribution based on the Lequesne Index of severity for osteoarthritis.

Figure 2

Box plot of median, first and third quartile of VAS values at different observation points.

Figure 3

Pain relief related to the various disabled classes obtained using Lequesne classification.

Figure 4

VAS values compared between patients treated under fluoroscopic guidance vs sonographic guidance.

Figure 5

Patients satisfaction recorded 180 days after procedure.