405: Genicular Peripheral Nerve Stimulation for Chronic Post-Surgical Knee Pain: A Case Series

Topic: Clinical Science
Subtopic: Pain category (ICD-11), Chronic primary musculoskeletal pain, Neuromodulation (e.g. TMS, TDCS, FUS, SCS, MCS, DBS, vagus nerve stimulation), Treatment/management

Background and Aims: Roughly 1 in 4 individuals in the United States experience chronic knee pain resulting in 4 million medical visits annually. The high prevalence manifests in enormous healthcare burden. Peripheral Nerve Stimulation (PNS) delivers electrical impulses to peripheral nerves to reduce pain by modulating central pathways. It is a treatment option in chronic pain patients who are not surgical candidates or who have undergone total knee arthroplasty (TKA) without success. It is a minimally invasive, surgically implanted, and reversible option associated with sustained pain relief (1). Here we present a retrospective case series of genicular nerve PNS for chronic knee pain.

Methods: Two 78- and 75-year-old females with multi-year chronic knee pain (baseline pain 8/10) despite TKA underwent implantation of a temporary (SPRINT, SPR Therapeutics) or permanent (Nalu, Nalu Medical) PNS system, respectively, between 2024-2025 at the University of California, Davis under fluoroscopic guidance with placement of two leads at the superior medial and lateral genicular nerves. For the Nalu system, leads were tunneled to the implanted pulse generator at the lateral upper thigh. The primary outcome was changes in self-reported percent pain relief at 1 week and 60 days for the temporary system and at 3 months for the permanent system.

Results: The first patient experienced approximately 10% pain relief at 1 week following SPRINT PNS placement. The device was reprogrammed at week 6 to optimize analgesia; however, at day 60, pain relief had increased only modestly to 15%. The second patient reported 90% relief of medial knee pain and 70% relief of lateral knee pain for five months following implantation of permanent Nalu PNS system after a successful trial. Unfortunately, the permanent system required explantation at month five due to infection at the implanted pulse generator site and was not reimplanted.

Conclusions: Post-TKA pain is a common condition with relatively sparse treatment options. PNS for chronic knee pain following TKA has its first documented use in 2010 (2). PNS targeting the genicular nerves represents a minimally invasive, cutting-edge treatment modality with the potential for durable, non-opioid analgesia in chronic pain (3). Unfortunately, techniques for PNS for post TKA pain are not standardized, and there is currently no consensus regarding optimal imaging guidance or nerve targets(4). While this case series reports encouraging findings, additional studies are needed to further elucidate long-term outcomes.

References: 1. Consensus Guidelines for the Use of PNS in the Treatment of Chronic Pain and Neurological Diseases: A Neuron Project from ASPN
2. Goree JH et al. Randomized Placebo-Controlled Trial of 60-Day Percutaneous PNS Treatment Indicates Relief of Persistent Postoperative Pain, and Improved Function After Knee Replacement. Neuromodulation. 2024;27:847-861. doi:10.1016/ j.neurom.2024.03.001
3. Kaye AD et al. PNS: A Review of Techniques and Clinical Efficacy. Pain Ther. 2021;10:961-972. doi:10.1007/ s40122-021-00298-1.
4. Früh A et al. Peripheral nerve stimulation for the treatment of chronic knee pain. Sci Rep. 2023;13. doi:10.1038/ s41598-023-42608-x.

Presenting Author: Naileshni Singh
Submitting Author: Naileshni Singh

Senior Author: Jason Petusevsky

IASP 2026 Global Year theme of Neuropathic Pain: Yes

• Jason Petusevsky: DO - University of California, Davis
• Chinar Sanghvi: MD - University of California, Davis
• Scott Pritzlaff: MD - University of California, Davis