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 evaluates whether Functional Magnetic Stimulation (FMS) can provide additional benefits when combined with a structured physiotherapy rehabilitation program in athletes with MRI-confirmed tibial bone stress injury and associated bone marrow edema. A total of 40 athletes with Fredericson grade 2 or 3 lesions are allocated to either a combined intervention group receiving FMS plus rehabilitation or a control group receiving rehabilitation alone. The intervention period lasts four weeks. Participants in both groups follow the same load-based rehabilitation program, while those in the FMS group also receive eight 30-minute FMS sessions. Assessments are performed at baseline, after the four-week intervention, and at 16 weeks. The evaluated outcomes include activity-related tibial pain, lower-limb functional ability, MRI-measured bone marrow edema extent, and Fredericson MRI grade. The purpose of the study is to examine whether adding FMS to standardized rehabilitation leads to greater clinical, functional, and MRI-derived improvement compared with rehabilitation alone.

Study Overview

• Status: Completed
• Conditions: Bone Marrow Edema
• Intervention / Treatment: Other: Standardized physiotherapy rehabilitation with FMS; Other: Standardized Physiotherapy without FMS

Detailed Description

Background: Tibial bone stress injury is a clinically relevant overuse condition in athletes and is commonly associated with bone marrow edema on magnetic resonance imaging. It typically presents with localized tibial pain during weight-bearing or sport-related loading and may interfere with training participation and return to activity. MRI is used to confirm the diagnosis, determine injury severity, and monitor structural recovery. Fredericson grades 2 and 3 represent tibial bone stress injuries with bone marrow edema but without a visible fracture line, and are usually treated conservatively through activity modification, graded loading, therapeutic exercise, and progressive rehabilitation. Functional Magnetic Stimulation (FMS) is a non-invasive electromagnetic intervention that can induce deep neuromuscular activation and may contribute to pain modulation, improved load tolerance, and local tissue responses. However, its role as an adjunctive intervention in athletes with MRI-confirmed tibial bone stress injury remains insufficiently investigated.

Aim: The aim of this randomized controlled clinical trial is to evaluate whether adding Functional Magnetic Stimulation to a standardized physiotherapy rehabilitation program provides additional benefits in athletes with MRI-confirmed tibial bone stress injury associated with bone marrow edema. The study examines whether the combined intervention leads to greater improvement in activity-related pain, lower-limb functional ability, and MRI-derived indicators of recovery compared with standardized rehabilitation alone.

Method: Forty athletes with MRI-confirmed tibial bone stress injury classified as Fredericson grade 2 or 3 are randomly allocated to two groups. The intervention group receives Functional Magnetic Stimulation in addition to a structured four-week physiotherapy rehabilitation program, while the control group receives the same rehabilitation program without FMS. The rehabilitation program is based on symptom-guided activity modification, progressive lower-limb loading, strengthening, mobility exercises, neuromuscular control, and gradual return to impact-based activity. FMS is applied twice weekly for four weeks, for a total of eight 30-minute sessions, over the symptomatic tibial region. Assessments are performed at baseline, at the end of the four-week intervention period, and at 16-week follow-up. Outcomes include activity-related tibial pain assessed with the Numerical Pain Rating Scale, lower-limb functional ability assessed with the Greek version of the Lower Extremity Functional Scale, MRI-derived bone marrow edema extent, and Fredericson MRI grade. Continuous outcomes are analyzed using repeated-measures mixed analysis of variance, while Fredericson grade is analyzed as an ordinal repeated-measures outcome.

Expected Results: It is expected that athletes receiving Functional Magnetic Stimulation in addition to standardized physiotherapy rehabilitation will demonstrate greater reductions in activity-related tibial pain, greater improvements in lower-limb functional ability, and more favorable MRI-derived recovery compared with athletes receiving rehabilitation alone. The findings are expected to clarify whether FMS may serve as a useful adjunctive modality within a structured rehabilitation approach for athletes with tibial bone stress injury.

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

Contacts and Locations

Study Locations

• Greece
  • Sindos
    • Thessaloniki, Sindos, Greece, 57400
      • Department of Physiotherapy, Faculty of Health Sciences International Hellenic University

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Age between 18 and 45 years.
• Regular participation in sports training at least three times per week during the previous six months.
• MRI-confirmed tibial bone stress injury classified as Fredericson grade 2 or grade 3.
• Localized tibial pain provoked by loading activity.
• Activity-related pain intensity of at least 3/10 on the Numeric Pain Rating Scale.
• Written informed consent provided before participation.

Exclusion Criteria:

• Fredericson grade 4 injury or visible fracture line on MRI.
• Bone marrow edema related to infection, tumor, systemic inflammatory disease, or another non-mechanical cause.
• History of fracture, surgery, or intra-articular/peri-osseous injection in the affected lower limb within the previous 12 weeks.
• Previous Functional Magnetic Stimulation or Extracorporeal Shockwave Therapy within the previous 8 weeks.
• Contraindications to magnetic stimulation, including pacemaker, implanted neurostimulator, cochlear implant, or significant metallic implant in or near the treatment area.
• Pregnancy or breastfeeding.
• Any neurological, metabolic, cardiovascular, or systemic condition that could affect safe participation or interpretation of study outcomes.

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: Functional Magnetic Stimulation plus standardized physiotherapy rehabilitation; Arm Description: Participants receive 12 physiotherapy rehabilitation sessions over four weeks plus eight 30-minute FMS sessions applied over the symptomatic tibial region.	Other: Standardized physiotherapy rehabilitation with FMS; Participants in this arm complete a supervised four-week rehabilitation program delivered three times per week, for a total of 12 sessions of approximately 45 minutes each. The program focuses on symptom-guided activity modification, progressive lower-limb loading, strengthening, mobility exercises, neuromuscular control, home-based exercise guidance, and gradual return to impact-related activity. In addition, participants receive Functional Magnetic Stimulation twice per week for four weeks, resulting in eight sessions in total. Each FMS session lasts 30 minutes and is applied over the symptomatic tibial region. Stimulation is delivered at 40 Hz, with repeated cycles of 3 seconds of stimulation followed by 6 seconds of rest. Intensity is increased gradually according to participant tolerance, while avoiding pain, excessive discomfort, or overly strong muscle contractions.
Active Comparator: Physiotherapy rehabilitation alone; Participants in this group complete 12 supervised physiotherapy rehabilitation sessions over a four-week period and do not receive Functional Magnetic Stimulation.	Other: Standardized Physiotherapy without FMS; Participants in this group will follow the same standardized 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
Change in tibial pain during a standardized walking task	Description: Pain related to loading of the affected tibia is measured with the Numeric Pain Rating Scale, an 11-point scale ranging from 0 to 10. A score of 0 indicates absence of pain, while a score of 10 indicates the highest possible pain intensity. At each assessment, participants complete a standardized treadmill walking task and report the greatest tibial pain experienced during the test. The walking speed selected at the initial assessment is kept the same for each participant at follow-up measurements, allowing pain to be evaluated under comparable loading conditions. Higher scores reflect greater symptom severity.	baseline, week 4, week 16

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in lower-limb functional ability with the Greek Version of the Lower Extremity Functional Scale (LEFS-GR)	Description: Lower-limb function is evaluated using the Greek version of the Lower Extremity Functional Scale. This patient-reported measure includes 20 items related to daily and sport-related activities involving the lower limb. Each item is scored from 0 to 4, and the total score ranges from 0 to 80. Lower scores indicate greater functional limitation, whereas higher scores reflect better lower-limb functional ability.	baseline, week 4, week 16
Change in MRI-derived bone marrow edema extent	Bone marrow edema is assessed using magnetic resonance imaging of the affected tibia. The extent of edema is measured on fluid-sensitive MRI sequences as the maximum visible longitudinal length of intramedullary edema. The measurement is recorded in centimeters, with lower values indicating a smaller extent of bone marrow edema.	baseline, week 4, week 16
Change in Fredericson MRI grade	Tibial bone stress injury severity is evaluated using the Fredericson MRI grading system. This classification ranges from grade 0 to grade 4, with lower grades indicating less severe MRI findings and grade 4 indicating the presence of a fracture line. Changes in Fredericson grade are assessed over time to monitor MRI-defined recovery.	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 (Actual): December 1, 2025
• Primary Completion (Actual): June 29, 2026
• Study Completion (Actual): June 29, 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): July 1, 2026
• Last Update Submitted That Met QC Criteria: June 29, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Keywords: Rehabilitation; Physiotherapy; Functional Magnetic Stimulation; Tibial 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