Shear-Wave Elastography of Regenerated Hamstring Tendons After ACL Reconstruction (SWE-ACL) (SWE-ACL)

May 23, 2026 updated by: Olcay Yavuz, Fatih Sultan Mehmet Training and Research Hospital

Quantitative Assessment of Regenerated Hamstring Tendon Elasticity Using Shear-Wave Elastography and Its Relationship With Isokinetic Muscle Strength and Clinical Outcomes After Anterior Cruciate Ligament Reconstruction

Anterior cruciate ligament (ACL) reconstruction using autologous hamstring tendon grafts is a commonly performed procedure. Although the semitendinosus and gracilis tendons demonstrate regeneration at the donor site, the structural and biomechanical properties of the regenerated tissue may differ from native tendon, potentially affecting muscle function.

This study aims to quantitatively assess the elasticity of regenerated hamstring tendons using shear-wave elastography (SWE) and to compare these measurements with the contralateral intact side. Additionally, the relationship between tendon elasticity and isokinetic hamstring muscle strength will be evaluated. Secondary objectives include investigating the association between elastography findings and functional clinical outcomes, as well as the effect of postoperative time and patient-related factors such as age and body mass index.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Anterior cruciate ligament reconstruction with autologous hamstring tendon grafts, typically using the semitendinosus and gracilis tendons, is widely used in orthopedic practice. Following graft harvesting, these tendons may regenerate over time; however, the regenerated tissue often demonstrates altered histological and biomechanical characteristics, including disorganized collagen structure and reduced type I collagen content. These changes may lead to decreased tendon elasticity and impaired force transmission, potentially contributing to deficits in muscle strength and functional performance.

Shear-wave elastography (SWE) is a non-invasive imaging modality that enables quantitative assessment of tissue stiffness by measuring elastic modulus or shear-wave velocity. This technique has increasingly been used to evaluate musculoskeletal tissues and may provide objective insight into tendon regeneration quality. Isokinetic dynamometry, on the other hand, allows precise measurement of muscle strength at different angular velocities and is widely used in functional assessment after ACL reconstruction.

The primary objective of this study is to evaluate the elasticity of regenerated semitendinosus and gracilis tendons using SWE in patients who have undergone ACL reconstruction with hamstring autografts. Elastography measurements will be compared with those obtained from the contralateral intact side. Furthermore, the association between tendon elasticity and isokinetic hamstring muscle strength will be analyzed.

Secondary objectives include examining the relationship between elastography findings and functional clinical scores, including the International Knee Documentation Committee (IKDC), Lysholm, and Tegner scores, as well as functional performance tests. The effect of postoperative duration will also be assessed by comparing early (6-12 months) and late (>12 months) postoperative periods. In addition, the influence of demographic factors such as age and body mass index on tendon elasticity and muscle strength will be evaluated.

This study is designed as a prospective cross-sectional observational study. Patients who have undergone ACL reconstruction with autologous hamstring grafts and have completed at least 6 months of postoperative follow-up will be included. Participants will undergo shear-wave elastography assessment of the hamstring tendons. Previously obtained magnetic resonance imaging (MRI) and isokinetic muscle strength (Cybex) data will be collected from institutional records. MRI will be evaluated for graft signal characteristics, tunnel position, and graft thickness, while isokinetic testing will provide quantitative measurements of hamstring strength at different angular velocities.

All data will be analyzed to determine correlations between tendon elasticity, muscle strength, imaging findings, and clinical outcomes. The findings of this study are expected to improve understanding of tendon regeneration following ACL reconstruction and may contribute to more individualized rehabilitation strategies and postoperative assessment using non-invasive biomarkers such as SWE.

Study Type

Observational

Enrollment (Actual)

29

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Turkey (Türkiye)
    • Istanbul
      • Ataşehir, Istanbul, Turkey (Türkiye), 34752
        • Fatih Sultan Mehmet Training and Research Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

N/A

Sampling Method

Non-Probability Sample

Study Population

The study population will consist of adult patients who have undergone anterior cruciate ligament (ACL) reconstruction using autologous hamstring tendon grafts (semitendinosus and gracilis) and have completed at least 6 months of postoperative follow-up. Participants will be selected from a single tertiary referral center and will have available postoperative magnetic resonance imaging (MRI) and isokinetic muscle strength (Cybex) data. All eligible patients will undergo shear-wave elastography (SWE) assessment of the regenerated hamstring tendons at the time of study enrollment.

Description

Inclusion Criteria:

  • Patients who have undergone anterior cruciate ligament (ACL) reconstruction using autologous hamstring tendon grafts (semitendinosus and gracilis)
  • At least 6 months of postoperative follow-up
  • Availability of postoperative magnetic resonance imaging (MRI) and isokinetic muscle strength (Cybex) measurements
  • Willingness to participate and provide informed consent

Exclusion Criteria:

  • History of previous surgery on the same lower extremity (other than the index ACL reconstruction)
  • Presence of neuromuscular disorders affecting lower extremity function
  • Incomplete clinical, imaging, or functional data
  • Inability to undergo elastography assessment

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
ACL Reconstruction With Hamstring Autograft
Patients who have undergone anterior cruciate ligament (ACL) reconstruction using autologous hamstring tendon grafts (semitendinosus and gracilis) and have completed at least 6 months of postoperative follow-up will be included. Participants will undergo shear-wave elastography (SWE) assessment of regenerated hamstring tendons. Previously obtained magnetic resonance imaging (MRI) and isokinetic muscle strength (Cybex) measurements will be collected from institutional records. Elastography measurements will be compared with the contralateral intact side, and associations with muscle strength, imaging findings, and functional clinical outcomes will be analyzed.
Other: Shear-Wave Elastography Assessment
Shear-Wave elastography (SWE) will be used to quantitatively assess the elasticity of regenerated hamstring tendons. Measurement will be obtained in kilopascal (kPa) or meters per second (m/s) and compared with the contralateral intact side. These values will be analyzed in relation to isokinetic muscle strength and clinical outcomes.
Other Names:
  • SWE, Elastography

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Elasticity of Regenerated Hamstring Tendons Measured by Shear-Wave Elastography
Time Frame: At a single postoperative assessment (≥6 months after surgery)
Quantitative assessment of the elasticity of regenerated semitendinosus and gracilis tendons using shear-wave elastography (SWE). Elasticity will be measured as Young's modulus (kilopascals, kPa) or shear-wave velocity (meters per second, m/s). Measurements will be obtained from the operated limb and compared with the contralateral intact side.
At a single postoperative assessment (≥6 months after surgery)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Isokinetic Hamstring Muscle Strength
Time Frame: At a single postoperative assessment (≥6 months after surgery)
Assessment of hamstring muscle strength using an isokinetic dynamometer (Cybex). Peak torque (Nm/kg) will be measured at angular velocities of 60°/s and 180°/s during concentric and eccentric contractions.
At a single postoperative assessment (≥6 months after surgery)
International Knee Documentation Committee (IKDC) Score
Time Frame: At a single postoperative assessment (≥6 months after surgery)
Patient-reported knee function assessed using the IKDC subjective knee evaluation form. Scores range from 0 to 100, with higher scores indicating better function.
At a single postoperative assessment (≥6 months after surgery)
Lysholm Knee Score
Time Frame: At a single postoperative assessment (≥6 months after surgery)
Functional knee status assessed using the Lysholm scoring system. Scores range from 0 to 100, with higher scores indicating better function.
At a single postoperative assessment (≥6 months after surgery)
Tegner Activity Scale
Time Frame: At a single postoperative assessment (≥6 months after surgery)
Activity level assessed using the Tegner scale, ranging from 0 (sick leave or disability) to 10 (competitive sports at elite level).
At a single postoperative assessment (≥6 months after surgery)
Graft Characteristics on MRI
Time Frame: MRI obtained during postoperative follow-up (≥6 months)
Evaluation of graft characteristics on MRI, including signal intensity using a grading-based evaluation method.
MRI obtained during postoperative follow-up (≥6 months)
Femoral and Tibial Tunnel Position on MRI
Time Frame: MRI obtained during postoperative follow-up (≥6 months after surgery)
Postoperative femoral and tibial tunnel position assessed on MRI using descriptive anatomic localization and position measurements.
MRI obtained during postoperative follow-up (≥6 months after surgery)
ACL Graft Thickness on MRI
Time Frame: MRI obtained during postoperative follow-up (≥6 months after surgery)
Postoperative ACL graft thickness measured on MRI in millimeters.
MRI obtained during postoperative follow-up (≥6 months after surgery)
Postoperative Duration Group Comparison
Time Frame: At a single postoperative assessment (6 and 12 months after surgery)
Comparison of tendon elasticity and muscle strength between early (6-12 months) and late (>12 months) postoperative groups.
At a single postoperative assessment (6 and 12 months after surgery)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Fatih Sultan Mehmet Training and Research Hospital

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

March 30, 2025

Primary Completion (Actual)

March 30, 2026

Study Completion (Actual)

April 30, 2026

Study Registration Dates

First Submitted

April 21, 2026

First Submitted That Met QC Criteria

April 21, 2026

First Posted (Actual)

April 29, 2026

Study Record Updates

Last Update Posted (Actual)

May 27, 2026

Last Update Submitted That Met QC Criteria

May 23, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • SWE-ACL-2026

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data (IPD) will not be shared.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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