A Comparison of ACL Repair With BEAR Device vs. Autograft Patellar Tendon ACL Reconstruction (BEAR-MOON)

August 27, 2026 updated by: Kurt Spindler, MD, The Cleveland Clinic

BEAR - MOON: A Two Arm Non-Inferiority Randomized Clinical Trial Comparing ACL Repair With BEAR Device vs. Autograft Patellar Tendon ACL Reconstruction

This study is designed to evaluate bridge-enhanced ACL restoration (BEAR), a new surgical technique for repairing knees injured by a tear of the anterior cruciate ligament (ACL) that promotes reattachment and healing of the ACL using a blood-enriched implant. BEAR will be compared to bone to patellar tendon to bone autograft (BPTB) reconstruction, a standard ACL surgical reconstruction technique that replaces a torn portion of the ACL with transplanted patellar tendon tissue, and thus requires additional invasive patellar tendon removal and reuse as a portion of the ACL surgery, in a two group randomized clinical trial (RCT) in which participants will have equal chance of receiving BEAR or BPTB reconstruction. The BEAR technique is FDA approved and involves surgically placing a sponge (the BEAR implant) between the torn ends of the ACL, providing an absorbable implant for the ligament ends to grow into. The investigators hypothesize that the ACL repair with BEAR technology will achieve results not appreciably worse than BPTB reconstruction, with a reduced burden of invasive surgery, when assessed over the first two post-operative years. Animal studies suggest BEAR may also ameliorate longer-term premature osteoarthritis of the knee, a common consequence of ACL reconstruction surgery. However, no human data yet support that, and this trial will conclude before such a benefit can be observed. All patients 18-55 years of age who are candidates for ACL surgery within 50 days of the ACL injury and who present to surgeons participating in the study will be offered participation in the trial. Patients will be randomized and will undergo specified rehabilitation protocols post-operatively with primary assessments of knee laxity and patient reported measures at 6 months, 1 year, and 2 years.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Active, not 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.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

The study population will include active and otherwise healthy patients of both genders, all races, and between 18-55 years old at any of six locations, who elect to undergo primary surgery for a torn ACL within 50 days of injury. Approximately 100 patients will receive each of the experimental BEAR surgery and the comparative control BPTB reconstruction surgery, with each group distributed similarly across the six medical centers where the trial is being conducted: Cleveland Clinic, Vanderbilt University, Ohio State University, Rhode Island Hospital/University Orthopedics, and University of Colorado . The study intervention uses a BEAR implant, which is placed between the torn ends of the ruptured ACL. The BEAR implant is resorbed over 4 to 8 weeks, during which period it promotes repair of the ACL tissue in the gap between the torn ends. The device provides a stable provisional sponge to facilitate intra-articular repair of the torn ACL ligament, where without the implant device, healing does not occur. The results of this BEAR procedure will be compared against ACL reconstruction using a BPTB autograft. This technique consists of removing the torn ACL tissue, harvesting patellar tendon, and grafting that tendon within tunnels in the bone to reconstruct or replace the torn ACL. The study duration is five years. Surgery will occur at most 50 days after the patient's ACL is torn, with two year follow-up and a three month window for the final follow-up examination, for a maximum enrollment period for each patient of approximately 2 years and five months (29 months). Randomization will occur during the surgery, and patients will be informed of their treatments at conclusion of their participation. The two research time points are 1 and 2 years, when assessments will be conducted by an independent examiner masked to the type of surgery the patient received. With the exception of the RCT consenting process, use of the BEAR implant, and the blinded assessment process, clinical care will be standard practice following surgical treatment for a torn ACL.

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.
Interventional

Enrollment (Actual)

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

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

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

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.
  • Name: Carrie B Melgaard, MS
  • Phone Number: (216)318-9094
  • Email: melgaac@ccf.org

Study Locations

  • United States
    • Colorado
      • Boulder, Colorado, United States, 80309
        • University of Colorado
    • Minnesota
      • Bloomington, Minnesota, United States, 55431
        • TRIA Orthopaedics Center/ University of Minnesota
    • Ohio
      • Cleveland, Ohio, United States, 44195
        • Cleveland Clinic
      • Columbus, Ohio, United States, 43202
        • Ohio State University
    • Rhode Island
      • Providence, Rhode Island, United States, 02906
        • University Orthopedics Institute/ Rhode Island Hospital
    • Tennessee
      • Nashville, Tennessee, United States, 37232
        • Vanderbilt University

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

18 years to 55 years (Adult)

Accepts Healthy Volunteers

No

Description

INCLUSION CRITERIA

In order to be eligible to participate in this study, an individual must meet all of the following criteria:

  1. 18-55 years of age
  2. Complete ACL tear as confirmed by MRI
  3. Selected surgical treatment of ACL injury
  4. Believed to be a surgical candidate for ACL reconstruction by treating physician
  5. Time from injury to surgery is ≤50 days
  6. Stated willingness to comply with all study procedures for the duration of the study, including lifestyle, activity, and sports restrictions
  7. Provision of signed and dated informed consent form

EXCLUSION CRITERIA AT PRE-OPERATIVE EXAM

An individual who meets any of the following criteria, either during a pre-operative exam or during intraoperative arthroscopic evaluation, will be excluded from participation in this study:

  1. Any prior ACL surgery on affected knee (except simple arthroscopy for plica, debris removal, or diagnosis)
  2. Any prior ACL surgery on unaffected knee (except simple arthroscopy for plica, debris removal, diagnosis or partial meniscectomy)
  3. Confirmed or suspected contralateral ACL tear
  4. ACL tear found to be only partial and the treating physician feels it does not require surgery because it is "stable"
  5. Diagnosis of posterolateral corner injury (complete lateral collateral ligament tear, biceps femoris tendon avulsion, arcuate ligament tear, popliteus ligament tear) that requires concurrent or staged surgical treatment
  6. Diagnosis of Grade III medial collateral injury that requires concurrent or staged surgery
  7. Insufficient ACL tissue on MRI
  8. Diagnosis of complete patellar dislocation
  9. Diagnosis of complete patellar tendon or quadriceps tear
  10. Obesity with a BMI ≥45
  11. Does not speak or understand English
  12. Daily smoking (occasional or social use is accepted if smoking ≤ 3 days/ week and ≤ 5 cigarettes/day)
  13. Documented history of illicit drug or alcohol abuse (except for recreational use of marijuana)
  14. Inability to take oral medications
  15. Use of intra-articular corticosteroids in the affected knee within last 6 months
  16. Chronic use of corticosteroids for treatment of an autoimmune disorder such as lupus, rheumatoid arthritis, etc. (maintenance or rescue inhaler for asthma is allowed)
  17. History of prior infection in knee
  18. History of chemotherapy treatment
  19. History of sickle cell disease
  20. History of anaphylaxis, requiring a documented medical intervention
  21. Any condition that, in the opinion of the investigator, could affect healing (e.g., diabetes, inflammatory arthritis, etc.)
  22. Pregnancy or lactation
  23. Known allergic reactions to meat products or collagen
  24. Known allergy to bovine collagen, bovine gelatin, or other bovine products
  25. Known adverse reaction to any bovine product
  26. Febrile illness within 7 days
  27. Treatment with another investigational drug or other intervention, either concurrently or previously, that would interfere with surgical healing
  28. Not considered by treating physician to be a good research candidate

EXCLUSION CRITERIA AT INTRAOPERATIVE ARTHROSCOPIC EVALUATION

  1. Time from injury to surgery has exceeded 50 days
  2. No ACL tear found upon arthroscopic inspection
  3. ACL tear found to be only partial, with normal pivot shift and endpoint, and does not require surgery
  4. Displaced bucket handle meniscal injury requiring repair
  5. Diagnosis of full-thickness chondral injury of Grade 3 or 4, or that requires more than microfracture (i.e., osteochondral autograft transplant), on either condyle
  6. Unrecognized lateral or medial sided Grade 3 ligamentous injury that requires concurrent or staged surgery
  7. Tibial stump length is < 1cm
  8. Tibial footprint attachment is < 50% intact
  9. Any other reason the ACL stump should be deemed irreparable (e.g., tissue quality too poor to hold suture)

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

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

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Active Comparator: ACL Reconstruction(BPTB Graft)
Procedure/Surgery ACL Reconstruction (Bone Patellar Tendon Bone Graft): Standard of care surgical procedure Patellar Tendon Autograft ACL reconstruction, in which a bone-patellar tendon-bone graft from the front of the knee is taken to replace the torn ACL.
Procedure: ACL Reconstruction (Bone Patellar Tendon Bone Graft)
Standard of care procedure Patellar Tendon Autograft ACL reconstruction, in which a bone-patellar tendon-bone graft from the front of the knee is taken to replace the torn ACL.
Experimental: Bridge Enhanced ACL Restoration
Procedure/Surgery Bridge Enhanced ACL Restoration (BEAR): The surgical repair of the ACL using the BEAR technique involves surgically placing a sponge (the BEAR implant) between the torn ends of the ACL, providing a sponge for the ligament ends to group into.
Device: Bridge Enhanced ACL Restoration (BEAR)
The BEAR technique involves surgically placing a sponge (the BEAR implant) between the torn ends of the ACL, providing a sponge for the ligament ends to group into.

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
KT-1000
Time Frame: KT-1000 instrumented knee laxity measure 2 years after surgery (difference from contralateral knee)
Co-primary Outcome measure: Knee stability or the antero-posterior (AP) knee laxity will be determined using a KT-1000 arthrometer at the 30lb force setting on both knees of the subject at 6 months, 1 and 2 years after surgery. The primary endpoint will be 2 year KT-1000. Both left and right knees will be covered with a sleeve so the trained examiner cannot tell which the operated knee is or which procedure the patient had. Values for both knees will be recorded. For knee laxity 2.5 mm in the side-to-side difference measurements will be taken as the non-inferiority margin for the 2 year post-operative comparison of patients in the bridge-enhanced repair group and the ACL reconstruction groups.Testing will be performed by experienced, certified athletic trainers, physical therapists or physician assistants trained using standardized equipment according to the MOON protocol.
KT-1000 instrumented knee laxity measure 2 years after surgery (difference from contralateral knee)
IKDC (International Knee Documentation Committee) Score
Time Frame: Validated Patient Reported IKDC Subjective Score Instrument 2 years after surgery (change from baseline)
The IKDC patient-reported outcome measure instrument will be completed by patients pre-operatively, then at 3 and 6 months, 1 year and at the final 2 year visit after surgery. The primary endpoint will be evaluated at 2 years. The IKDC non-inferiority margin for BEAR vs. autograft patellar tendon will be set at <16 points. The IKDC is a patient reported outcome measure which contains sections on knee symptoms (7 items), function (2 items), and sports activities (2 items). Scores range from 0 points (lowest level of function or highest level of symptoms) to 100 points (highest level of function and lowest level of symptoms).
Validated Patient Reported IKDC Subjective Score Instrument 2 years after surgery (change from baseline)

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
The Knee Injury and Osteoarthritis Outcome Score (KOOS)
Time Frame: Validated Patient Reported KOOS Subjective Score Instrument 2 years after surgery
The Knee Injury and Osteoarthritis Outcome Score (KOOS) is a patient-reported outcome measurement instrument to assess the patient's opinion about their knee and associated problems. The KOOS evaluates both short and long-term consequences of knee injury and primary osteoarthritis. It is a validated patient-reported outcomes measure to be administered by the research coordinator at the same time points as the IKDC (preoperatively, 3 and 6 months, 1 and 2 years). There are 5 subscales (Pain, Symptoms, Activities of Daily Living (ADL), Sports and Recreation, and Knee related Quality of life). The minimum clinically relevant difference is 8 points on a 100 point scale for each of the five subscales.The last week is taken into consideration when answering the questions. Standardized answer options are given and each question gets a score from 0 to 4. A normalized score (100 indicating no symptoms and 0 indicating extreme symptoms) is calculated for each subscale.
Validated Patient Reported KOOS Subjective Score Instrument 2 years after surgery
MARX Activity (Marx Activity Rating Scale)
Time Frame: MARX Activity 2 years after surgery
The Marx Activity Scale is a validated patient-reported measure to be administered by the research coordinator to the patient preoperatively and at 1 and 2 years post-operatively. MARX focuses on four activity points: running, deceleration, cutting (changing directions while running), and pivoting. Patients are asked to indicate approximately how many times in the past 12 months they performed each of the activities while at their healthiest and most active state. The four knee functions are rated on a 5-point scale of frequency and scores are added up to a maximum of 16 points with a higher score indicating more frequent participation. The MARX rating scale is not based on participation in specific sporting activities. Instead, patients are asked about different components of physical function (e.g., running and pivoting) that are common to different sports.
MARX Activity 2 years after surgery
Anterior Knee Pain Scale (AKPS)
Time Frame: AKPS 2 years after surgery
The AKPS is a validated patient-reported outcomes measure to be administered by the research coordinator to patients at the same time points as the IKDC (preoperatively, 3 and 6 months, 1 and 2 years). This tool is designed to measure patellofemoral pain symptoms. The BEAR-MOON study will utilize the 6-item short version (walking, squatting, jumping, pain, swelling, abnormal kneecap movements). Minimum score is 0 points (most painful) and maximum score is 100 points (no pain).
AKPS 2 years after surgery
Quadriceps Strength Testing
Time Frame: Quadriceps Strength 2 years after surgery
Measurement of quadriceps strength on both knees will be performed at 6 months, and 1 and 2 years after surgery using a hand held dynamometer. Both sides will be covered with a sleeve so the blinded examiner cannot tell which the knee was the operated knee or which procedure was performed. Values for both knees will be recorded.
Quadriceps Strength 2 years after surgery
Hop Test Limb Difference
Time Frame: Hop Test Limb Difference 2 years after surgery
Hop functional testing will be performed by a trained physical therapist or athletic trainer on a strict protocol as performed and published by MOON. This will be performed at 6 month, 1 and 2 years. The measurement of interest is the difference between hop distances using the normal leg and ACL injured leg. Single leg hop tests are a method to determine ability to return to high-level athletics following knee surgery. They are commonly used during the return to function phase in an anterior cruciate ligament (ACL) rehabilitation protocol to assess the functional stability of the knee
Hop Test Limb Difference 2 years after surgery
Active Knee Range of Motion
Time Frame: Active Knee Range of Motion 2 years after surgery
Range of motion will be measured using a goniometer. Both sides will be covered with a sleeve so the licensed examiner cannot tell which the knee was the operated knee or which procedure was performed. Values for both knees will be recorded.
Active Knee Range of Motion 2 years after surgery
Lachman Testing
Time Frame: Lachman Testing 2 years after surgery
The Lachman Test will be measured by a blinded examiner at 6 months, 1 year and at the final 2 year visit after surgery. Both knees will be covered with a sleeve in order to keep the assessor blinded to the operative knee and which procedure was performed. The Lachman test is used to identify the integrity of the ACL.
Lachman Testing 2 years after surgery
Number of Participants with Knee Infection
Time Frame: Knee Infection 2 years after surgery
Infection is defined as a return to the operating room for a washout of the knee; intravenous (IV) antibiotics to treat the infection.
Knee Infection 2 years after surgery
Number of Participants with Treatment Failure
Time Frame: Treatment Failure 2 years after surgery
Treatment failure will include re-injury; knee laxity >6mm without re-injury; MRI confirmation of graft tear; or a physical examination that proves a graft tear.
Treatment Failure 2 years 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.
The Cleveland Clinic

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Miach Orthopaedics

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Kurt P Spindler, MD, The Cleveland Clinic

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)

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.
August 30, 2021

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.
July 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.
December 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).
December 13, 2018

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.
December 13, 2018

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.
December 14, 2018

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 31, 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 27, 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

Keywords

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.
  • G180167
  • R01AR074131-01 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

The public will have access to the published results of the NIH funded research. Scientists will be required to submit final peer-reviewed journal manuscripts that arise from NIH funds to the digital archive PubMed Central upon acceptance for publication.

IPD Sharing Time Frame

Per National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) policy, 2 years after posting of study results.

IPD Sharing Access Criteria

This study will comply with the NIH Data Sharing Policy on the Dissemination of NIH-Funded Clinical Trial Information and the Clinical Trials Registration and Results Information Submission rule.

IPD Sharing Supporting Information Type

  • CSR

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

product manufactured in and exported from the U.S.

No

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