Differences in Outcomes and Failure Rates Between Allografts and Autografts in Revision Anterior Cruciate Ligament Reconstruction (ACLREV_GRAFT)

August 3, 2026 updated by: Stefano Zaffagnini

Anterior cruciate ligament (ACL) rupture is one of the most common knee injuries, particularly in young and physically active individuals. Despite advances in reconstruction techniques, graft failure and rerupture remain clinically relevant. Revision ACL surgery is more complex than primary reconstruction and is associated with inferior outcomes, with rerupture rates of approximately 13%, reaching up to 25% when both subjective and objective failure criteria are considered.

The main goal of ACL reconstruction is to restore anteroposterior and rotational knee stability, prevent secondary meniscal and cartilage damage, and enable return to sport. Surgical outcomes depend on several intraoperative factors, including graft choice and tunnel geometry, which are particularly relevant in revision settings.

Diagnosis of ACL rerupture is primarily clinical, based on instability tests (Lachman, anterior drawer, pivot shift), and supported by instrumental assessment such as the KT-1000 arthrometer, which provides an objective measure of joint laxity.

Revision ACL reconstruction can be performed using different surgical techniques (single-bundle, double-bundle, or combined extra-articular procedures) and graft types (autograft or allograft). Surgical strategy depends on multiple factors such as meniscal and cartilage status, previous surgery characteristics, tunnel positioning/enlargement, and fixation devices. However, no consensus exists regarding the optimal approach in terms of mid- to long-term outcomes.

A major long-term complication is the development of osteoarthritis, particularly in this typically young and active patient population. Identification of modifiable factors, such as surgical technique and graft type, may help reduce failure risk and joint degeneration.

This study aims to evaluate clinical and radiographic outcomes over a follow-up period exceeding two years in patients undergoing revision ACL reconstruction with different surgical techniques and graft types. The study also integrates objective knee laxity assessment using KT-1000 and markerless motion analysis based on artificial intelligence. Functional movements are recorded via video and analyzed using Sports2D software, enabling 2D kinematic analysis without markers or sensors, providing quantitative functional data to complement clinical and radiographic evaluation.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
150

Contacts and Locations

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

Study Contact

Study Contact

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Study Locations

  • Italy
    • Bologna
      • Bologna, Bologna, Italy, 40136
        • Recruiting
        • IRCCS Rizzoli Orthopedic Institute
        • Contact:

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

No

Sampling Method

Probability Sample

Study Population

Patients will be recruited among all subjects who underwent revision anterior cruciate ligament reconstruction at the SC Orthopaedic and Trauma Clinic II of the Istituto Ortopedico Rizzoli, with at least 2 years between the surgical procedure and the clinical-radiological reassessment proposed in this study, from 01/01/2016 to 31/12/2024 at the Istituto Ortopedico Rizzoli. Such reassessment is part of routine clinical practice.

Description

Inclusion Criteria:

  • Age 18-50 years at the time of surgery
  • Male and female patients
  • Patients undergoing revision anterior cruciate ligament (ACL) reconstruction with possible associated procedures, with at least 2 years of follow-up
  • Written informed consent to participate in the study

Exclusion criteria:

  • Patients lost to follow-up
  • Refusal to provide informed consent
  • Advanced knee osteoarthritis (Outerbridge grade III-IV) at the time of surgery
  • Severe obesity (BMI > 35)
  • Lower limb conditions preventing full weight-bearing standing during evaluation
  • Active infection, hematologic disease, or rheumatologic disease at the time of 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

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Survival rate
Time Frame: At least 24 months after surgery
Failures will be recorded and documented in the case report form (CRF), during telephone questionnaires, and through the patient's clinical records (Electronic Health Record, SIR 2020, and hospital databases). The survival rate at follow-up will then be estimated using a Kaplan-Meier survival curve
At least 24 months after surgery

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Lysholm Knee Score
Time Frame: At least 24 months after surgery

It is a validated measurement scale that assesses knee function through 8 items, allowing evaluation of knee condition in relation to the functional demands of activities of daily living. This assessment form is used to evaluate surgical outcomes in patients undergoing surgery for ligamentous or meniscal knee injuries.

The final score is obtained by summing the scores of the individual items and ranges from 0 to 100. Scores are categorized into subgroups as follows: Excellent (95-100); Good (84-94); Fair (65-83); Poor (<64)
At least 24 months after surgery
International Knee Documentation Committee - Objective Knee Evaluation Form
Time Frame: At least 24 months after surgery

The objective IKDC is a clinical assessment form completed by the investigator, which allows standardized classification of knee status through objective parameters. The evaluation is based on four main domains: joint effusion, range of motion, ligament stability (in particular Lachman test, pivot-shift test, and anterior/posterior drawer tests), and joint compartments (meniscal and ligament examination).

The final outcome is not expressed as a continuous numerical score, but rather as a classification into four categories:

A (Normal) B (Nearly normal) C (Abnormal) D (Severely abnormal)

The final classification corresponds to the worst score obtained among the evaluated domains.
At least 24 months after surgery
Anterior drawer test
Time Frame: At least 24 months after surgery
It allows assessment of anterior tibial translation relative to the femur with the knee flexed at 90 degrees. An increased translation suggests a lesion of the reconstructed ACL (neo-ACL). It is graded on a scale from 0 to 3
At least 24 months after surgery
Lachman test
Time Frame: At least 24 months after surgery
It allows assessment of anterior tibial translation relative to the femur with the knee flexed at 30 degrees. Increased translation suggests a lesion of the reconstructed ACL (neo-ACL). It is graded on a scale from 0 to 3
At least 24 months after surgery
Pivot shift test
Time Frame: At least 24 months after surgery
This is a clinical examination maneuver used to assess rotational instability of the knee. The test is performed by applying a valgus and internal rotation stress during knee flexion; the occurrence of a tibial "shift" or "clunk" suggests a lesion of the reconstructed ACL (neo-ACL) associated with rotational instability. It is graded on a scale from 0 to 3.
At least 24 months after surgery
Tegner Activity Scale
Time Frame: At least 24 months after surgery

The Tegner Score is a physical activity rating scale that measures the level of participation in occupational and sports activities. The score ranges from 0 to 10, where:

0 indicates inability to work or severe disability due to knee problems;

10 indicates participation in competitive sports at national or international level (e.g., professional football).

Intermediate levels describe progressively more demanding physical activities, distinguishing between activities of daily living, light or heavy work, and recreational or competitive sports.

The Tegner Score is frequently used in combination with other instruments (such as the IKDC or Lysholm scores) to define the patient's functional level before injury and after treatment. In the context of this study, the score is collected through a direct patient interview conducted by the investigator.
At least 24 months after surgery
WOMAC
Time Frame: At least 24 months after surgery

The WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) is a self-administered questionnaire specifically developed to assess patients with hip and knee osteoarthritis. The instrument evaluates the impact of the disease on pain, stiffness, and physical function.

The questionnaire consists of 24 items divided into three main domains:

  • Pain (5 items)
  • Joint stiffness (2 items)
  • Physical function (17 items)

The total score is normalized on a 0-100 scale.
At least 24 months after surgery
KT-1000
Time Frame: At least 24 months after surgery
The KT-1000 is an objective assessment device that measures anterior tibial translation relative to the femur by applying a predefined force to translate the tibia anteriorly. Its use is part of routine clinical practice in the outpatient setting of the Second Orthopaedic and Trauma Clinic of the IOR and aims to quantitatively assess static anteroposterior knee laxity following anterior cruciate ligament reconstruction. The unit of measurement is millimetres
At least 24 months after surgery
Post-operative movement analysis
Time Frame: At least 24 months after surgery

Knee function will be assessed during functional tasks (walking, lunges, squat) using a markerless AI-based video analysis system (Sports2D). The software estimates 2D joint kinematics (hip, knee, ankle, trunk) from videos recorded in frontal and sagittal planes without the use of sensors or markers. The system is non-invasive, already used in clinical practice, and installed locally to ensure data protection.

Videos are processed through an internal MATLAB script that extracts kinematic outputs (.mot and .trc files) using automated AI-based analysis. Data are anonymized via alphanumeric IDs, and videos are deleted after processing to minimize data retention.
At least 24 months after surgery

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Stefano Zaffagnini

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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
July 8, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
May 1, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
May 1, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
June 22, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 22, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
June 26, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
August 4, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 3, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
August 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • ACLREV_GRAFT

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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