Clinical Trials Study
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Orthop. Oct 18, 2021; 12(10): 781-790
Published online Oct 18, 2021. doi: 10.5312/wjo.v12.i10.781
Short-term effectiveness of high- and low-intensity percutaneous electrolysis in patients with patellofemoral pain syndrome: A pilot study
Juan Antonio Valera-Calero, Alberto Sánchez-Mayoral-Martín, Umut Varol
Juan Antonio Valera-Calero, Alberto Sánchez-Mayoral-Martín, Department of Physiotherapy, Camilo Jose Cela University, Madrid 28692, Spain
Umut Varol, Business Analytics and Big Data, IE School of Human Sciences and Technology, Madrid 28006, Spain
Author contributions: Valera-Calero JA conceived and designed the study; Valera-Calero JA, Varol U, and Sánchez-Mayoral-Martín A contributed to data acquisition; Valera-Calero JA analyzed and interpreted the data; Valera-Calero JA drafted and critically revised the manuscript; Valera-Calero JA contributed to the statistical analysis and supervised the study.
Institutional review board statement: This manuscript was revised and approved by the Institutional Ethics Committee of Clinical Research of Alfonso X el Sabio University (UAX 26-02-2020).
Clinical trial registration statement: The study protocol is prospectively registered and available at (NCT04390438).
Informed consent statement: All participants read and signed a written consent prior to their participation in the study.
Conflict-of-interest statement: The authors declared no potential conflicts of interest.
Data sharing statement: The data that support the findings of this study are available from the corresponding author (JA Valera-Calero), upon reasonable request.
CONSORT 2010 statement: This clinical trial followed the CONSORT for pragmatic clinical trials.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Corresponding author: Juan Antonio Valera-Calero, MSc, PhD, Physiotherapist, Professor, Physiotherapy, Camilo Jose Cela University, Calle castillo de Alarcón 49, Madrid 28692, Spain.
Received: February 26, 2021
Peer-review started: February 26, 2021
First decision: May 3, 2021
Revised: May 3, 2021
Accepted: August 4, 2021
Article in press: August 4, 2021
Published online: October 18, 2021

Unilateral patellofemoral pain syndrome (PFPS) is the most frequently diagnosed knee condition in populations aged < 50 years old. Although the treatment of myofascial trigger points (MTrPs) is a common and effective tool for reducing pain, previous studies showed no additional benefits compared with placebo in populations with PFPS. Percutaneous electrolysis is a minimally invasive approach frequently used in musculotendinous pathologies which consists of the application of a galvanic current through dry needling (DN).


To evaluate changes in sensitivity, knee pain perception and perceived pain during the application of these three invasive techniques.


A triple-blinded, pilot randomized controlled trial was conducted on fifteen patients with unilateral PFPS who were randomized to the high-intensity percutaneous electrolysis (HIPE) experimental group, low-intensity percutaneous electrolysis (LIPE) experimental group or DN active control group. All interventions were conducted in the most active MTrP, in the rectus femoris muscle. The HIPE group received a 660 mA galvanic current for 10 s, the LIPE group 220 mA × 30 s and the DN group received no galvanic current. The MTrP and patellar tendon pain pressure thresholds (PPTs) and subjective anterior knee pain perception (SAKPP) were assessed before, after and 7 d after the single intervention. In addition, perceived pain during the intervention was also assessed.


Both groups were comparable at baseline as no significant differences were found for age, height, weight, body mass index, PPTs or SAKPP. No adverse events were reported during or after the interventions. A significant decrease in SAKPP (both HIPE and LIPE, P < 0.01) and increased patellar tendon PPT (all, P < 0.001) were found, with no differences between the groups (VAS: F = 0.30; η2 = 0.05; P > 0.05; tendon PPT immediate effects: F = 0.15; η2 = 0.02; P > 0.05 and tendon PPT 7-d effects: F = 0.67; η2 = 0.10; P > 0.05). A significant PPT increase in rectus femoris MTrP was found at follow-up in both the HIPE and LIPE groups (both, P < 0.001) with no differences between the groups (immediate effects: F= 1.55; η2 = 0.20; P > 0.05 and 7-d effects: F = 0.71; η2 = 0.10; P > 0.05). Both HIPE and LIPE interventions were considered less painful compared with DN (F = 8.52; η2 = 0.587; P < 0.01).


HIPE and LIPE induce PPT changes in MTrPs and patellar tendon and improvements in SAKPP, and seem to produce less pain during the intervention compared with DN.

Keywords: Patellofemoral pain syndrome, Electrolysis, Myofascial pain syndromes, Dry needling, Clinical trial

Core Tip: Percutaneous electrolysis is a minimally invasive approach frequently used in lower limb musculotendinous pathologies which consists of the application of a galvanic current through a dry needling (DN) or acupuncture needle which acts as a negative electrode, increasing the pH and cellular necrosis by a local electrochemical reaction. However, the current evidence regarding its application in myofascial trigger points (MTrPs) is limited. Therefore, the aim of this study was to assess the efficacy of percutaneous electrolysis compared with DN in patients with unilateral patellofemoral pain syndrome to improve rectus femoris MTrP and patellar tendon pain pressure thresholds, subjective anterior knee pain perception and induced pain during interventions.