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NCT Number: NCT07446517

Low-Level Laser Therapy for Osgood-Schlatter or Sever Pain in Youth Athletes

The goal of this clinical trial is to learn if low-level laser therapy (also called photobiomodulation) works to treat knee or heel pain in physically active children and adolescents with Osgood-Schlatter disease or Sever disease. It will also learn about the safety of this treatment. The main questions it aims to answer are:

1. Does low-level laser therapy lower pain more than a sham (placebo) laser treatment? 2. Does low-level laser therapy improve daily and sport-related function more than a sham laser treatment? 3. What medical problems, if any, do participants have during the study?

Researchers will compare active low-level laser therapy to a sham (placebo) laser treatment. The sham treatment looks and feels the same but does not deliver therapeutic light. This comparison will show whether the laser therapy works better than placebo.

Participants will:

* Complete screening and a baseline visit * Be randomly assigned to active laser therapy or sham laser therapy * Receive a series of treatment sessions over [2 weeks] * Answer short questionnaires about pain and function at baseline and follow-up visits * Have ultrasound imaging and/or provide blood or urine samples for research measurements

Both participants and the study team who assess outcomes will not know which treatment group each participant is in until the study ends.

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Key information

Conditions

Osgood-Schlatter Disease Bone Diseases Musculoskeletal Diseases Osteochondrosis Sever's Disease

Age range

10 year–17 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Department of Immunobiology and Environment Microbiology, Debinki 7

Gdansk, Pomeranian, 80-210, Poland

Location status: Recruiting

Location contact

Bartosz Wilczyński, PhD

CONTACT

[email protected]

58 349 17 66 ext. +48

About this study

This pilot randomized, placebo-controlled, double-masked clinical trial evaluates the feasibility and preliminary clinical signal of laser photobiomodulation (low-level laser therapy; LLLT) in youth athletes (10-17 years) with symptomatic lower-extremity apophyseal pathology, primarily consistent with Osgood-Schlatter disease and/or calcaneal apophysitis (Sever disease) confirmed clinically and by ultrasound.

Participants will be randomized 1:1 to active LLLT or sham LLLT. The intervention consists of 10 sessions over 2 weeks (5 sessions/week) delivered with a class 3B GaAlAs (Gallium-Aluminum-Arsenide) laser device using standardized parameters (near-infrared wavelength range; continuous mode; preset energy density; contact application over the symptomatic apophyseal region). Sham procedures are identical in appearance, session duration, and device operation but deliver 0 mW output.

The primary objective is feasibility (recruitment, retention, adherence, data completeness, safety). Secondary objectives are estimate-only between-group differences in pain and function at post-intervention and follow-up. Mechanistic measures (biomarkers and ultrasound features) are exploratory and used to inform the design of a future full-scale trial.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Aged 10 to 17 years
  • Participates in organized sport with at least 12 months of training history
  • Has knee pain at the tibial tubercle (Osgood-Schlatter-type pain) and/or heel pain at the back of the heel (Sever-type pain)
  • Pain is worse with activity and reproduced by pressing on the painful area
  • Pain intensity is 3 out of 10 or higher on the Numeric Pain Rating Scale (NPRS) during the clinical visit and in the last week (0 = no pain, 10 = worst pain imaginable)
  • Symptoms have been present for at least 2 weeks
  • For heel pain consistent with Sever disease, the heel squeeze test is positive
  • Ultrasound shows findings consistent with an apophyseal injury at the painful site
  • Has no signs of acute illness or infection on the assessment day and during the previous 14 days (for example, fever or "flu-like" symptoms)
  • A parent/guardian provides written informed consent
  • The participant provides assent (agreement) to take part

Exclusion criteria

  • Current pain episode started after an acute injury (for example, fall, collision, ankle sprain, or similar trauma)
  • Prior surgery on the lower limb
  • Known diagnosis of patellofemoral pain syndrome (pain around/behind the kneecap)
  • Known patellar instability (recurrent kneecap dislocations or giving way)
  • Known complex regional pain syndrome
  • History of lower-limb fracture
  • Ultrasound shows clinically important abnormalities in the assessed area that are not consistent with the target condition (for example, calcifications or other significant findings)
  • Known chronic or systemic disease that may affect the musculoskeletal system (for example, inflammatory joint disease or other clinically significant chronic conditions)
  • Received any of the following in the last 3 months: steroid injection, hydrodilatation, or laser therapy
  • Used non-steroidal anti-inflammatory drugs (NSAIDs) (for example, ibuprofen, naproxen) within the last 14 days, or currently uses them
  • Clinically important abnormal blood test results (complete blood count) that may affect safety or data validity
  • Parent/guardian or participant does not agree to participate, or withdraws consent/assent

Treatment and study plan

Photobiomodulation (Low-Level Laser Therapy)

Device

Active photobiomodulation (low-level laser therapy) delivered using a laser device applied to the symptomatic apophyseal region (tibial tubercle for Osgood-Schlatter-type pain and/or calcaneal region for Sever-type pain). Sessions will be provided according to a standardized schedule and preset device parameters (wavelength/output/dose and application time) specified in the protocol.

Other names: Low-Level Laser Therapy, Laser Photobiomodulation

Sham Photobiomodulation (Sham Laser Treatment)

Device

Sham (placebo) photobiomodulation delivered with an identical device appearance and treatment routine (positioning, contact, and session duration) but without delivery of therapeutic light. The sham procedure is intended to maintain participant blinding and matches the active intervention schedule.

Other names: Placebo Laser Treatment, Inactive Laser Treatment

Primary outcomes

  1. Recruitment feasibility: proportion of eligible participants enrolled

    Time frame: From first screening contact through completion of enrollment.

    Proportion enrolled among eligible candidates; threshold ≥80% within the recruitment window.

  2. Retention feasibility: proportion completing post-intervention and follow-up assessments

    Time frame: Baseline to post-intervention (≈2 weeks) and baseline to follow-up (≈3 months).

    Proportion with complete assessments at baseline and post-intervention; threshold ≤20% attrition.

  3. Adherence feasibility: proportion of intervention sessions completed

    Time frame: During the 2-week intervention period.

    Percentage of planned sessions completed (10 total); threshold ≥8/10 sessions and ≥80% adherence.

  4. Data completeness feasibility: proportion of complete datasets for key clinical outcomes

    Time frame: Baseline to follow-up (≈3 months).

    Proportion of participants with complete NPRS/PGIC/PODCI; threshold ≥90% complete.

  5. Safety and tolerability: number and type of adverse events related to the intervention

    Time frame: During the 2-week intervention period.

    Count and classification of adverse events temporally associated with treatment sessions.

Secondary outcomes

  1. Proportion of Participants Rated as Responders on the Patient Global Impression of Change (PGIC) at 2 Weeks

    Time frame: 2 weeks

    PGIC is a 7-point global change scale from "very much improved" to "very much worse." A responder is defined as "much improved" or "very much improved".

  2. Proportion of Participants Rated as Responders on the Patient Global Impression of Change (PGIC) at 3 Months

    Time frame: 3 months

    PGIC is a 7-point global change scale from "very much improved" to "very much worse." A responder is defined as "much improved" or "very much improved."

  3. Change From Baseline in Pain Intensity as Measured by the Numeric Pain Rating Scale (NPRS) at 2 Weeks

    Time frame: Baseline and 2 weeks

    NPRS ranges from 0 to 10, where 0 = no pain and 10 = worst pain imaginable. Pain intensity refers to worst pain in the last 7 days. The metric is change from baseline to 2 weeks.

  4. Change From Baseline in Pain Intensity as Measured by the Numeric Pain Rating Scale (NPRS) at 3 Months

    Time frame: Baseline and 3 months

    NPRS ranges from 0 to 10, where 0 = no pain and 10 = worst pain imaginable. Pain intensity refers to worst pain in the last 7 days. The metric is change from baseline to 3 months.

  5. Change From Baseline in Pediatric Function as Measured by the Pediatric Outcomes Data Collection Instrument (PODCI) at 2 Weeks

    Time frame: Baseline and 2 weeks

    PODCI domain scores are standardized from 0 to 100, where higher scores indicate better function/well-being. The metric is change from baseline to 2 weeks

  6. Change From Baseline in Pediatric Function as Measured by the Pediatric Outcomes Data Collection Instrument (PODCI) at 3 Months

    Time frame: Baseline and 3 months

    PODCI domain scores are standardized from 0 to 100, where higher scores indicate better function/well-being. The metric is change from baseline to 3 months.

  7. Change From Baseline in Knee Function as Measured by the KOOS-Child at 2 Weeks (Osgood-Schlatter Subgroup)

    Time frame: Baseline and 2 weeks

    KOOS-Child subscale scores are transformed to a 0 to 100 scale, where higher scores indicate better knee status (fewer symptoms/better function). The metric is change from baseline to 2 weeks, assessed in the Osgood-Schlatter subgroup only.

  8. Change From Baseline in Knee Function as Measured by the KOOS-Child at 3 Months (Osgood-Schlatter Subgroup)

    Time frame: Baseline and 3 months

    KOOS-Child subscale scores are transformed to a 0 to 100 scale, where higher scores indicate better knee status. The metric is change from baseline to 3 months, assessed in the Osgood-Schlatter subgroup only.

  9. Change From Baseline in Foot/Ankle Function (OxAFQ-C) at Post-intervention (2 weeks), Sever Subgroup Only

    Time frame: Baseline and 2 weeks

    OxAFQ-C domains 0-100 (higher=better). Metric: change from baseline to ≈2 weeks. Assessed only in Sever participants.

  10. Change From Baseline in Foot/Ankle Function (OxAFQ-C) at Follow-up (3 months), Sever Subgroup Only

    Time frame: Baseline and 3 months

    OxAFQ-C domains 0-100 (higher=better). Metric: change from baseline to 3 months.

Other outcomes

  1. Change From Baseline in Ultrasound Features of the Symptomatic Apophysis at 2 Weeks

    Time frame: Baseline and 2 weeks

    Musculoskeletal ultrasound of the index symptomatic apophyseal site using a standardized acquisition protocol (high-frequency linear probe; fixed patient position). Predefined features will be graded on ordinal scales and summed into a prespecified composite "ultrasound severity score" (higher = greater abnormality). Features include: (1) apophyseal fragmentation/irregularity, (2) tendon insertion thickening, (3) hypoechogenicity, (4) bursal fluid/soft-tissue swelling. Metric: change in composite score from baseline to 2 weeks.

  2. Change From Baseline in C-Reactive Protein at 2 Weeks

    Time frame: Baseline and 2 weeks

    Serum concentration of C-reactive protein (CRP), measured using enzyme-linked immunosorbent assay (ELISA) per protocol. Metric: change from baseline to 2 weeks. Unit of measure: per ELISA kit manufacturer instructions (e.g., mg/L); values will be converted to a single standard unit for CRP prior to analysis.

  3. Change From Baseline in Interleukin-6 at 2 Weeks

    Time frame: Baseline and 2 weeks.

    Serum concentration of interleukin-6 (IL-6), measured using enzyme-linked immunosorbent assay (ELISA) per protocol. Metric: change from baseline to 2 weeks. Unit of measure: per ELISA kit manufacturer instructions (e.g., pg/mL); values will be converted to a single standard unit for IL-6 prior to analysis.

  4. Change From Baseline in Tumor Necrosis Factor-Alpha at 2 Weeks

    Time frame: Baseline and 2 weeks.

    Serum concentration of tumor necrosis factor-alpha (TNF-α), measured using enzyme-linked immunosorbent assay (ELISA) per protocol. Metric: change from baseline to 2 weeks. Unit of measure: per ELISA kit manufacturer instructions (e.g., pg/mL); values will be converted to a single standard unit for TNF-α prior to analysis.

  5. Change From Baseline in C-Terminal Cross-Linked Telopeptide of Type II Collagen at 2 Weeks

    Time frame: Baseline and 2 weeks

    Serum concentration of C-terminal cross-linked telopeptide of type II collagen (CTX-II), measured using enzyme-linked immunosorbent assay (ELISA) per protocol. Metric: change from baseline to 2 weeks. Unit of measure: per ELISA kit manufacturer instructions (e.g., pg/mL or ng/mL); values will be converted to a single standard unit for CTX-II prior to analysis.

  6. Change From Baseline in Type II Collagen Cleavage Neoepitope at 2 Weeks

    Time frame: Baseline and 2 weeks.

    Serum concentration of type II collagen cleavage neoepitope (C2C), measured using enzyme-linked immunosorbent assay (ELISA) per protocol. Metric: change from baseline to 2 weeks. Unit of measure: per ELISA kit manufacturer instructions (e.g., pg/mL or ng/mL); values will be converted to a single standard unit for C2C prior to analysis.

  7. Change From Baseline in C-Propeptide of Type II Procollagen at 2 Weeks

    Time frame: Baseline and 2 weeks.

    Serum concentration of C-propeptide of type II procollagen (CPII), measured using enzyme-linked immunosorbent assay (ELISA) per protocol. Metric: change from baseline to 2 weeks. Unit of measure: per ELISA kit manufacturer instructions (e.g., pg/mL or ng/mL); values will be converted to a single standard unit for CPII prior to analysis.

  8. Treatment Expectancy and Credibility (TEC-C / TEC-P) at Baseline (Pre-intervention)

    Time frame: Pre-intervention (baseline), prior to the first treatment session and prior to functional testing.

    Treatment expectancy and credibility will be assessed in the child and parent/caregiver using pediatric versions of the Treatment Expectancy and Credibility measure (TEC-C and TEC-P). The child and caregiver complete the questionnaires independently (without influence on each other's responses). Scores are derived per instrument instructions (higher scores indicate greater expectancy/credibility).

  9. Change From Baseline in Cartilage Oligomeric Matrix Protein at 2 Weeks

    Time frame: Baseline and 2 weeks.

    Serum concentration of cartilage oligomeric matrix protein (COMP), measured using enzyme-linked immunosorbent assay (ELISA) per protocol. Metric: change from baseline to 2 weeks. Unit of measure: per ELISA kit manufacturer instructions (e.g., ng/mL); values will be converted to a single standard unit for COMP prior to analysis.

  10. Change From Baseline in Procollagen Type I N-Terminal Propeptide at 2 Weeks

    Time frame: Baseline and 2 weeks

    Serum concentration of procollagen type I N-terminal propeptide (PINP), measured using enzyme-linked immunosorbent assay (ELISA) per protocol. Metric: change from baseline to 2 weeks. Unit of measure: per ELISA kit manufacturer instructions (e.g., ng/mL); values will be converted to a single standard unit for PINP prior to analysis.

  11. Change From Baseline in Beta C-Terminal Telopeptide of Type I Collagen at 2 Weeks

    Time frame: Baseline and 2 weeks.

    Serum concentration of beta C-terminal telopeptide of type I collagen (β-CTX), measured using enzyme-linked immunosorbent assay (ELISA) per protocol. Metric: change from baseline to 2 weeks. Unit of measure: per ELISA kit manufacturer instructions (e.g., pg/mL or ng/mL); values will be converted to a single standard unit for β-CTX prior to analysis.

  12. Change From Baseline in Tartrate-Resistant Acid Phosphatase 5b at 2 Weeks

    Time frame: Baseline and 2 weeks

    Serum concentration or activity of tartrate-resistant acid phosphatase 5b (TRAP-5b), measured using enzyme-linked immunosorbent assay (ELISA) per protocol. Metric: change from baseline to 2 weeks. Unit of measure: per ELISA kit manufacturer instructions (e.g., U/L or ng/mL); values will be converted to a single standard unit for TRAP-5b prior to analysis.

  13. Change From Baseline in Osteocalcin at 2 Weeks

    Time frame: Baseline and 2 weeks.

    Serum concentration of osteocalcin, measured using enzyme-linked immunosorbent assay (ELISA) per protocol. Metric: change from baseline to 2 weeks. Unit of measure: per ELISA kit manufacturer instructions (e.g., ng/mL); values will be converted to a single standard unit for osteocalcin prior to analysis.

  14. Change From Baseline in Bone-Specific Alkaline Phosphatase at 2 Weeks

    Time frame: Baseline and 2 weeks.

    Serum bone-specific alkaline phosphatase (BAP), measured per protocol (assay name per project documentation; if "Ostase/Ostease" is the assay, write it exactly as used by the lab). Metric: change from baseline to 2 weeks.

  15. Change From Baseline in Total Serum Calcium at 2 Weeks

    Time frame: Baseline and 2 weeks.

    Total serum calcium concentration, measured using laboratory assay per protocol. Metric: change from baseline to 2 weeks. Unit of measure: per laboratory assay (e.g., mmol/L or mg/dL); values will be converted to a single standard unit for total serum calcium prior to analysis if required.

  16. Change From Baseline in 25-Hydroxyvitamin D at 2 Weeks

    Time frame: Baseline and 2 weeks.

    Serum 25-hydroxyvitamin D (25(OH)D), measured using laboratory assay per protocol. Metric: change from baseline to 2 weeks. Unit of measure: ng/mL (or nmol/L) per laboratory assay; values will be converted to a single standard unit for 25(OH)D prior to analysis if required.

  17. Change From Baseline in 1,25-Dihydroxyvitamin D at 2 Weeks

    Time frame: Baseline and 2 weeks.

    Serum 1,25-dihydroxyvitamin D (1,25(OH)₂D), measured using laboratory assay per protocol. Metric: change from baseline to 2 weeks. Unit of measure: pg/mL (or pmol/L) per laboratory assay; values will be converted to a single standard unit for 1,25(OH)₂D prior to analysis if required.

  18. Change From Baseline in Bone-Specific Alkaline Phosphatase at 2 Weeks

    Time frame: Baseline and 2 weeks.

    Serum concentration or activity of bone-specific alkaline phosphatase (BAP), measured using enzyme-linked immunosorbent assay (ELISA) per protocol (assay name per project documentation, if applicable). Metric: change from baseline to 2 weeks. Unit of measure: per ELISA kit manufacturer instructions (e.g., U/L or µg/L); values will be converted to a single standard unit for BAP prior to analysis.

Study contacts

Contact information is provided by the study sponsor or research team.

Bartosz Wilczyński, PhD

CONTACT

[email protected]

+48 732 414 195

Sponsors and collaborators

Lead sponsor

Medical University of Gdansk

Other

Registry information

Official study title

Effect of Low-Level Laser Photobiomodulation on Pain, Function, Ultrasound Findings, and Biochemical Markers in Youth Athletes With Osgood-Schlatter Disease or Sever Disease: A Randomized, Double-Blind, Sham-Controlled Trial

Important dates

Study start
2026
Primary completion
2027
Study completion
2029
First posted
Mar 3, 2026
Registry last updated
Mar 17, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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