Effectiveness of non-invasive ultrasound-guided electrical stimulation of genicular nerves for chronic knee pain: A case report.

RATIONALE

Chronic knee pain is a common health issue that requires effective and noninvasive treatment. We devised a novel noninvasive approach using ultrasound-guided electrical nerve reactivation (ENR) in which ultrasound is used to identify the genicular nerve (GN). Then, transcutaneous low-frequency stimulation is applied for 10 seconds. The aim of this study was to clarify the pain-relieving effects of ENR on the GN innervating the knee joint.

PATIENT CONCERNS

Patients had visited our hospital with the complaint of knee joint pain.

DIAGNOSES

This study included 21 osteoarthritic knees from 16 patients with a mean age of 78.3 ± 8.5 years.

INTERVENTIONS

Baseline measurements included the range of motion of the knee joint, Visual Analogue Scale (VAS) scores for pain, and maximum knee flexion angle during squatting. A therapist conducted an interview to locate the painful area of the knee and then performed ultrasound-guided ENR by targeting the GN.

OUTCOMES

The preintervention VAS score was 49.3 (95% confidence interval: 41.0, 57.5). Postintervention VAS scores showed significant reductions: 27.0 (19.0, 35.1) immediately after the intervention (P < .0001), 27.7 (22.6, 32.8) at 1-day postintervention (P = .002), and 29.0 (22.9, 35.1) at 1-week postintervention (P = .001). The knee flexion angle during squatting significantly improved from 108.1° (101.6, 114.5) preintervention to 121.9° (115.1, 128.7) postintervention (P < .001). There was a significant increase in flexion angle preintervention and postintervention (P = .02); however, no significant change was observed in the extension angle. In addition, no adverse events were reported.

LESSONS

This study is the first to demonstrate the effects of ultrasound-guided low-frequency stimulation of the GN for knee osteoarthritis. Although the exact mechanism of pain relief is unclear, we hypothesize that alterations in neurotransmission, with or without endorphin release, may play a role. Moreover, ENR may improve nerve entrapment by causing contraction of surrounding muscles.This study demonstrated that ultrasound-guided ENR targets the GN and effectively reduces pain without complications. This treatment addresses the limitations of invasive methods, such as hydrorelease and radiofrequency ablation. Furthermore, ultrasound-guided ENR has diverse applications in diagnostics, physical therapy, and pre-exercise pain management and will greatly benefit patients and healthcare professionals.