Infrapatellar Branch of the Saphenous Nerve: Therapeutic Approaches to Chronic Knee Pain.

PURPOSE OF REVIEW: The infrapatellar branch of the saphenous nerve (IPS) is an under-investigated nerve that can be a source of chronic knee pain. This literature review aims to deliver an up-to-date review of chronic pain transmitted via the IPS along with therapeutic approaches available for pain refractory to conservative measures. RECENT FINDINGS: Knee pain transmitted via the IPS can arise from several etiologies. Damage to the IPS is often iatrogenic and develops following total knee arthroplasty, anterior cruciate ligament reconstruction, and other knee surgical procedures. Other causes of IPS-derived pain include entrapment of the nerve, neuromas, Schwannomas, and pain from knee osteoarthritis transmitted through the IPS.This article investigated therapeutic approaches to pain derived from the IPS. Common approaches included radiofrequency ablation, neuroma excisions, Schwannoma excision, nerve blocks, surgical exploration, surgical release of an entrapped nerve, cryoablation, and peripheral nerve stimulation. Pain scores, duration of pain relief, adverse events, and secondary outcomes were all included in this review. A subset of the patient population experiences chronic pain deriving from the IPS that is refractory to conservative treatment measures. This review aims to evaluate the etiologies and therapeutic approaches for chronic pain arising from the IPS refractory to conservative treatments.

Efficacy of Cooled-Radiofrequency Ablation of the Genicular Nerve as Treatment for Chronic Knee Pain: A Retrospective Study.

INTRODUCTION: Chronic pain is one of the leading causes of reduced quality of life in the USA, with knee pain commonly reported. Multiple therapeutic modalities are traditionally utilized for pain management; however, some patients may have pain refractory to these techniques. Cooled radiofrequency ablation (c-RFA) of the geniculate nerve is a growing and promising therapy offering a potentially long-term solution to chronic knee pain. METHODS: This study assessed the efficacy, average duration of relief, and potential adverse events using a retrospective chart review of 406 procedures. A two-tailed paired t test was used to assess the statistical significance between pre-RFA vs. post-RFA visual analog scale (VAS) pain scores self-reported by patients. An analysis of variance (ANOVA) test was used to evaluate for statistical differences in pre-RFA pain scores and post-RFA pain scores among the categories of age, sex, body mass index (BMI), and diagnosis group. RESULTS: The mean percent in pain improvement calculated was 65.5% with an average duration of relief of 7.20 months. The average pre-RFA pain score on the VAS was 6.26 out of 10 and 2.59 out of 10 post-RFA. The ANOVA post-RFA pain scores demonstrated statistically significant differences among the categories of age and sex. A total of 54 adverse events were reported, including worsening pain, numbness, paresthesia, and knee swelling. CONCLUSION: The study demonstrated that c-RFA can potentially be utilized as an alternative safe therapy for chronic knee pain, providing pain relief with a relatively prolonged duration. Inherent challenges of retrospective studies remain a part of the limitations of this study.