Functional Magnetic Stimulation (FMS) for Bone Marrow Edema in Athletes

The Effectiveness of Functional Magnetic Stimulation in the Physiotherapeutic Rehabilitation of Athletes With Bone Marrow Edema: A Randomized Controlled Trial

This randomized controlled trial investigates the effectiveness of Functional Magnetic Stimulation (FMS) as an adjunct to physiotherapy in athletes with MRI-confirmed bone marrow edema of the lower limb. Forty athletes with Fredericson grade 2-3 edema will be randomly assigned to receive either physiotherapy plus FMS or physiotherapy alone for four weeks. Clinical, functional, and imaging assessments will be conducted up to 16 weeks. Primary outcomes include pain intensity, lower-limb function, return-to-sport readiness, and MRI indicators of bone marrow edema. The study aims to determine whether adjunctive FMS enhances recovery and accelerates the resolution of bone marrow edema compared with standard physiotherapy.

Study Overview

• Status: Recruiting
• Conditions: Bone Marrow Edema
• Intervention / Treatment: Other: Conventional Physiotherapy with FMS; Other: Conventional Physiotherapy without FMS

Detailed Description

Background: Bone marrow edema is a reversible stress-related bone injury in athletes, causing localized pain during loading and confirmed by MRI, the gold standard for diagnosis and monitoring. Grades 2 and 3 of the Fredericson classification represent clinically significant edema without a fracture line and are managed conservatively through physiotherapy including exercise, manual techniques, and gradual reloading. Functional Magnetic Stimulation (FMS) is a non-invasive method that induces deep neuromuscular activation and improves circulation. Although increasingly used in musculoskeletal rehabilitation, its effect on recovery from bone marrow edema has not yet been tested in a controlled clinical setting.

Aim: The aim of the present randomized controlled clinical trial is to evaluate the effectiveness of adding Functional Magnetic Stimulation to a structured physiotherapy rehabilitation program in athletes with MRI-confirmed bone marrow edema of the lower limb. The primary objective is to determine whether the combined approach results in greater clinical improvement, superior functional recovery, and faster radiological resolution of edema compared with physiotherapy alone.

Method: Forty athletes with lower-limb bone marrow edema graded as Fredericson 2 or 3 on MRI will be randomly assigned to two groups. The intervention group will follow a four-week physiotherapy program combining therapeutic exercise, manual therapy, and unloading techniques with Functional Magnetic Stimulation applied twice weekly. The control group will receive the same physiotherapy without FMS. Assessments will occur at baseline, two, four, and sixteen weeks, including pain (NRS 0-10), functional ability (LEFS-GR), and readiness for return to sport (Tegner scale). MRI at baseline, week 4, and week 16 will evaluate Fredericson grade, edema intensity, and edema extent. All parameters are predefined as primary outcomes. Data will be analyzed with mixed-model ANOVA for repeated measures with the significance level set at p < .05.

Expected Results: It is anticipated that athletes receiving Functional Magnetic Stimulation in addition to physiotherapy will show greater pain reduction, improved lower-limb function, faster MRI-documented resolution of bone marrow edema, and earlier readiness to return to sport compared with physiotherapy alone.

• Study Type: Interventional
• Enrollment (Estimated): 40
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Dimitrios Lytras, PhD; Phone Number: 0030 2310013802; Email: lytrasde@gmail.com
• Study Contact Backup: Name: Paris Iakovidis, PhD; Phone Number: 0030 2310013802; Email: paris_physio@yahoo.com

Study Locations

• Greece
  • Sindos
    • Thessaloniki, Sindos, Greece, 57400
      • Recruiting
      • Department of Physiotherapy, Faculty of Health Sciences International Hellenic University
      • Contact: Dimitrios Lytras, PhD; Phone Number: 0030 6945713359; Email: lytrasde@gmail.com
      • Contact: Paris Iakovidis, PhD; Phone Number: 0033 2310013802; Email: paris_physio@yahoo.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Athletes aged 18-45 years participating in regular sports training ≥3 sessions per week for the past 6 months.
• MRI-confirmed bone marrow edema (BME) of the lower limb graded as Fredericson 2 or 3.
• Onset of pain or symptoms within the previous 6 weeks.
• Pain intensity ≥4/10 on the Numeric Rating Scale during loading activity.
• Ability to comply with the 4-week intervention and 16-week follow-up assessments.
• Written informed consent provided prior to participation.

Exclusion Criteria:

• Fredericson grade 4 or evidence of a fracture line on MRI. Bone marrow edema secondary to infection, tumor, or systemic inflammatory disease.
• History of recent fracture, surgery, or intra-articular injection in the affected limb within 12 weeks.
• Prior exposure to Functional Magnetic Stimulation or Extracorporeal Shockwave Therapy within 8 weeks before enrollment.
• Presence of metallic implants, pacemaker, or other contraindications to magnetic stimulation.

Pregnancy or breastfeeding. Use of systemic corticosteroids or medications affecting bone metabolism. Any neurological, metabolic, or cardiovascular condition interfering with safe participation.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Physiotherapy plus Functional Magnetic Stimulation (FMS); Participants allocated to this group will receive 12 sessions of a conventional physiotherapy protocol and 8 sessions of FMS.	Other: Conventional Physiotherapy with FMS; Participants will receive a standardized four-week physiotherapy program, three sessions per week (12 sessions in total), each lasting approximately 45 minutes. Treatment will include therapeutic exercise for progressive strengthening and flexibility, manual therapy for pain modulation, and unloading-reloading strategies to restore functional load tolerance. Exercises will be tailored to the recovery stage, and participants will be instructed on home exercises and activity modification. In addition, participants will receive Functional Magnetic Stimulation (FMS) twice weekly for four weeks (eight sessions in total). Each session will last 30 minutes. FMS will be applied directly over the affected region using a fixed frequency of 40 Hz without modulation. The stimulation duty cycle will consist of an active phase of 3 seconds followed by a rest period of 6 seconds. Intensity will be gradually adjusted to patient tolerance avoding scomfort or excessive contraction.
Active Comparator: Physiotherapy without Functional Magnetic Stimulation (FMS); Participants allocated to this group will receive 12 sessions of a conventional physiotherapy protocol without the FMS	Other: Conventional Physiotherapy without FMS; Participants in this group will follow the same conventional physiotherapy protocol as the first group, without the application of FMS

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in pain intensity with Numeric Rating Scale (NPRS)	This tool is an eleven-point pain scale numbered from zero to 10. The left end of the scale corresponds to zero and is marked as "No pain", whereas the right end corresponds to 10 and is marked as "Maximum pain". Consequently, a higher value indicates more intense pain (Childs et al, 2005). The examinee is asked to choose an integer that best reflects the intensity of their pain. Participants will be asked to rate their pain under three conditions: at rest, during standardized loading of the affected limb, and during hypothetical return to sport.The NPRS is widely used to measure pain in both clinical practice and research, showing high test-retest reliability and high conceptual construct validity.	pre-treatment, week 4, Week 16
Changes in lower-limb functional ability with the Greek Version of the Lower Extremity Functional Scale (LEFS-GR)	The LEFS-GR is a self-reported questionnaire consisting of 20 items that assess the degree of difficulty in performing everyday and sport-related lower-limb activities. Each item is rated on a 5-point scale (0 = extreme difficulty or unable to perform; 4 = no difficulty), yielding a total score from 0 to 80, with higher scores indicating better functional ability. The Greek version of the LEFS has demonstrated excellent internal consistency (Cronbach's α = 0.974) and test-retest reliability (ICC = 0.986, p < 0.001) in individuals with lower-limb musculoskeletal disorders (Stasi et al., 2012).	baseline, week 4, week 16
Changes in bone marrow edema characteristics with Magnetic Resonance Imaging (MRI)	Magnetic Resonance Imaging (MRI) will be used to evaluate changes in bone marrow edema (BME) according to the Fredericson classification, which grades stress-related bone injury from 0 (normal) to 4 (cortical fracture). MRI scans will include T1-weighted and fat-suppressed T2/STIR sequences obtained under identical imaging parameters at all time points. Semi-quantitative analysis will be performed to record (a) Fredericson grade, (b) bone marrow edema signal intensity on a 0-3 scale, and (c) edema extent as a percentage of the total bone volume.	baseline, week 4, week 16
Changes in return-to-sport readiness with the Tegner Activity Scale and perceived sport pain	The Tegner Activity Scale (TAS) is an 11-level ordinal scale designed to evaluate physical activity and sports participation following lower-limb injury. It ranges from 0 (inability to work or perform daily activities due to symptoms) to 10 (participation in competitive sports at national or elite level). The validated Greek version (Gr-TAS) demonstrates high internal consistency (Cronbach's α = 0.89) and test-retest reliability (ICC = 0.97) in musculoskeletal populations (Panagopoulos et al., 2020). In this study, the scale will be combined with a perceived sport-related pain score (NRS 0-10), where higher TAS scores and lower pain scores will indicate greater readiness to return to sport.	baseline, week 4, week 16

Collaborators and Investigators

• Sponsor: International Hellenic University
• Investigators: Study Chair: Paris Iakovidis, PhD, International Hellenic University

Study record dates

Study Major Dates

• Study Start (Estimated): November 15, 2025
• Primary Completion (Estimated): September 15, 2026
• Study Completion (Estimated): September 15, 2026

Study Registration Dates

• First Submitted: November 14, 2025
• First Submitted That Met QC Criteria: November 14, 2025
• First Posted (Actual): November 18, 2025

Study Record Updates

• Last Update Posted (Actual): November 18, 2025
• Last Update Submitted That Met QC Criteria: November 14, 2025
• Last Verified: November 1, 2025

More Information

Terms related to this study

• Keywords: Rehabilitation; Physiotherapy; Functional Magnetic Stimulation; Bone Stress Injury
• Other Study ID Numbers: EC-15/2025

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No