Management of Focal Cartilage Lesions of the Knee: The Benefits of an Autograft Procedure (CART-MCI Knee)

June 9, 2026 updated by: Louis Pasteur Santé Lorraine

Cartilage is a tissue whose primary function is to transmit and distribute loads when joints are under stress. It acts as a buffer between bones at the joints. Over time, or due to diseases and/or trauma, this surface can disappear, leading to pain and limited movement. Cartilage lesions are particularly difficult to treat because cartilage has a limited capacity for regeneration.

When cartilage lesions are characterized by a localized defect, several surgical techniques are available to restore cartilage tissue to the affected area.

The most frequently used surgical technique is bone marrow stimulation, also known as microfracture. The cartilage lesion is debrided, the subchondral bone exposed, and then a punch is used to perforate the subchondral bone, allowing a clot to form within the defect. This clot will proliferate and differentiate into scar tissue. However, this cellular differentiation results in fibrocartilaginous tissue rather than hyaline cartilage, sometimes with disappointing clinical outcomes.

Other techniques for cartilage restoration exist and are used routinely, including more biological techniques such as Minced Cartilage Implantation (MCI). Autologous cartilage is first harvested from around the defect, chopped into very small fragments, and then reimplanted. Cartilage fragmentation activates cell proliferation and migration, followed by the synthesis of an extracellular, cartilaginous matrix. The effectiveness of this fragmentation is increased with fine fragments (<0.3 mm). Cell proliferation and activity appear to be stimulated by the systematic addition of PRP (Platelet-Rich Plasma) during the MCI procedure.

The expected benefit of an MCI approach lies in clinical improvement and better cartilage regeneration (observed on imaging) compared to microfracture.

The objective is to conduct a controlled, randomized, blinded study (blinded to both the patient and the MRI assessor of the bone graft) to determine the benefit of an MCI approach versus microfracture.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Objective : Primary objective: To demonstrate the benefit of the MCI approach in terms of lesion filling at 24 months post-surgery.

Secondary objectives:

  • To demonstrate the clinical benefit (based on functional scores and the need for re-intervention) of the MCI approach at different follow-up visits.
  • To describe all post-operative complications.
  • To demonstrate the benefit of the MCI approach in terms of lesion filling at 24 months post-surgery in patients with lesions larger than 2 cm².

Outcome Measures :

Primary endpoint: Bone grafting will be measured by magnetic resonance imaging at 24 months using the MOCART score (Magnetic Resonance Observation of Cartilage Repair Tissue 2.0 Knee Score), which assesses the rate and quality of grafting. The evaluator will be blinded to the randomization arm.

Secondary endpoints:

  • Functional scores at baseline, at 3, 9, and 24 months:
  • Visual Analog Scale (VAS)
  • Self Knee Value (SKV)
  • Knee Injury and Osteoarthritis Outcome Score (KOOS score)
  • and Tegner-Lysholm activity score
  • Postoperative complications from all causes at each visit
  • Need for reoperation at 3, 9, and 24 months post-surgery.

Single-center, controlled, randomized, blinded (patient and MRI assessor blinded), two parallel arms with a 1:1 ratio:

  • Arm 1: Microfractures
  • Arm 2: Minced Cartilage Implantation (MCI)

Randomization will be stratified by:

  • Age (< 30 years vs ≥ 30 years)
  • Lesion size (< 2 cm² vs ≥ 2 cm²)

Inclusion criteria:

  • Male or female, aged over 18 years.
  • Patient who has signed an informed consent form.
  • Patient with focal cartilage lesions of the knee, classified as grade 4 on MRI according to the International Cartilage Repair Society classification (exposure of subchondral bone), regardless of their size, and for which surgery is indicated.
  • Be affiliated with a social security scheme or a beneficiary of such a scheme

Exclusion criteria:

  • Revision knee surgery
  • Body Mass Index (BMI) > 27 kg/m2
  • Joint space narrowing on standard radiographic examination
  • Refusal of consent
  • Patient unable to read, write, or understand French
  • Vulnerable patient according to Article L1121-6 of the French Public Health Code (CSP)
  • Adult patient under guardianship, curatorship, or legal protection
  • Patient unable to personally give consent according to Article L.1121-8 of the French Public Health Code (CSP) or an adult protected by law
  • Pregnant or breastfeeding woman according to Article L1121-5 of the French Public Health Code (CSP)
  • Patient who has already participated in a study within the last 12 months
  • Patient already enrolled in another ongoing clinical trial

For patients randomized to the Microfracture arm, the procedure will be as follows: under arthroscopy, the lesion is prepared by debriding it.

Using a specific punch, perforations are made perpendicular to the exposed bone surface.

The technical principles are as follows:

  • Perforation depth: approximately 3 to 4 mm, allowing access to the bone marrow,
  • Regular spacing between perforations: 3 to 4 mm,
  • Preservation of the integrity of the interfracture bone bridges to avoid excessive weakening of the bone endplate.

For patients randomized to the MCI arm, the procedure will be as follows: during surgery, after visualization and debridement of the lesion, cartilage tissue is harvested from a low-weight, and therefore low-stress, area. This cartilage tissue is then fragmented and mixed with PRP (Platelet-Rich Plasma), collected from the patient's blood. Platelets are unique in that they have a high concentration of universal growth factors, enabling them to heal virtually all organic tissues. Adding PRP to the fragmented cartilage tissue promotes cartilage regeneration and the incorporation of the graft into the lesion. To ensure the graft adheres to the bone tissue, it is secured biologically (with thrombin). Post-operative recovery is typical, with a gradual return to walking and other activities.

The participant participation scheme is as follows:

  • Baseline: clinical examination + MRI + self-administered questionnaires
  • Inclusion and randomization after eligibility verification
  • Day 0: surgical intervention according to randomization (MCI vs. microfractures)
  • Discharge from hospital: clinical examination + complications
  • Post-surgery visit (M3 +/- 1 month): clinical examination + self-administered questionnaires + complications + need for re-surgery
  • Post-surgery visit (M9 +/- 1 month): clinical examination + self-administered questionnaires + complications + need for re-surgery
  • Post-surgery visit (M24 +/- 1 month): clinical examination + MRI with MOCART score calculation + self-administered questionnaires + complications + need for re-surgery

To demonstrate a difference in filling rate of 30 points (90% in the MCI arm versus 60% in the Microfractures arm) with a standard deviation of 40%, a type I error rate of 5%, and a power of 80%, 28 evaluable subjects per arm are required. To account for unanalyzable data and the potential for patients lost to follow-up, we propose including a total of 80 subjects (40 per arm) in this study.

Study Type

Interventional

Enrollment (Estimated)

80

Phase

  • 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 Locations

  • France
    • Grand Est
      • Essey-lès-Nancy, Grand Est, France, 54270
        • Clinique Louis Pasteur - Louis Pasteur Santé Lorraine
        • Contact:
        • Principal Investigator:
          • Frank WEIN

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
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Male or female, aged over 18 years.
  • Patient who has signed an informed consent form.
  • Patient with focal cartilage lesions of the knee, classified as grade 4 on MRI according to the International Cartilage Repair Society classification (exposure of subchondral bone), regardless of size, and for which surgery is indicated.
  • Be affiliated with or a beneficiary of a social security scheme.

Exclusion Criteria:

  • Revision knee surgery
  • Body Mass Index (BMI) > 27 kg/m²
  • Joint space narrowing on standard radiographic examination
  • Refusal of consent
  • Patient unable to read, write, or understand French
  • Vulnerable patient according to Article L1121-6 of the French Public Health Code (CSP)
  • Adult patient under guardianship, curatorship, or legal protection
  • Patient unable to give Personally, their consent according to Article L.1121-8 of the French Public Health Code (CSP) or an adult protected by law
  • Pregnant or breastfeeding woman according to Article L1121-5 of the French Public Health Code (CSP)
  • Patient who has already participated in a study within the last 12 months
  • Patient already enrolled in another ongoing clinical trial

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: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Arm 1: Microfractures

For patients randomized to the Microfracture arm, the procedure will be as follows: under arthroscopy, the lesion is prepared by debriding it.

Using a specific punch, perforations are made perpendicular to the exposed bone surface.

The technical principles are as follows:

  • Perforation depth: approximately 3 to 4 mm, allowing access to the bone marrow,
  • Regular spacing between perforations: 3 to 4 mm,
  • Preservation of the integrity of the interfracture bone bridges to avoid excessive weakening of the bone endplate.
Procedure: Management of focal cartilage lesions of the knee: micro-fracture

Patients will be randomized in the study to:

  • Either the Microfracture arm
  • Or the Minced Cartilage Implantation (MCI) arm
Other Names:
  • Management of focal cartilage lesions of the knee: Minced Cartilage Implantation (MCI)
Experimental: Arm 2: Minced Cartilage Implantation (MCI)
For patients randomized to the MCI arm, the procedure will be as follows: during surgery, after visualization and debridement of the lesion, cartilage tissue is harvested from a low-weight, and therefore low-stress, area. This cartilage tissue is then fragmented and mixed with PRP (Platelet-Rich Plasma), collected from the patient's blood. Platelets are unique in their high concentration of universal growth factors, and therefore have the ability to promote the healing of almost all organic tissues. This addition of PRP to the fragmented cartilage tissue will thus promote cartilage regeneration and the incorporation of the graft within the lesion. To ensure the graft adheres to the bone tissue, the entire structure is secured biologically (thrombin). Postoperative recovery is standard, with a gradual resumption of walking and activities.
Procedure: Minced Cartilage Implantation (MCI)

Patients will be randomized in the study to:

  • Either the Microfracture arm
  • Or the Minced Cartilage Implantation (MCI) arm

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Bone grafting
Time Frame: at 24 months after surgery
Bone grafting will be measured by magnetic resonance imaging at 24 months using the MOCART score (Magnetic Resonance Observation of Cartilage Repair Tissue 2.0 Knee Score), which assesses the rate and quality of grafting. The evaluator will be blinded to the randomization arm.
at 24 months after surgery

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Functional scores
Time Frame: Baseline, at 3 months, 9 months, 24 months after surgery

Scores fonctionnels :

- Visual Analogic Scale (VAS)
Baseline, at 3 months, 9 months, 24 months after surgery
Functional scores
Time Frame: Baseline 3 months, 9 months, 24 months after surgery

Scores fonctionnels :

- Self Knee Value (SKV)
Baseline 3 months, 9 months, 24 months after surgery
Functional scores
Time Frame: Baseline 3 months, 9 months, 24 months after surgery
Functional scores : Knee Injury and Osteoarthritis Outcome Score (KOOS score)
Baseline 3 months, 9 months, 24 months after surgery
Functional scores
Time Frame: Baseline 3 months, 9 months and 24 months after surgery
Tegner Lysholm activity score
Baseline 3 months, 9 months and 24 months after surgery
Post-operative complications
Time Frame: Immediately after surgery until max. 96 hours after surgery (corresponding to hospital discharge), 3 months, 9 months, 24 months after surgery
Post-operative complications of all causes
Immediately after surgery until max. 96 hours after surgery (corresponding to hospital discharge), 3 months, 9 months, 24 months after surgery
Re-intervention required
Time Frame: at 3, 9, and 24 months post-surgery
Re-intervention required
at 3, 9, and 24 months post-surgery

Collaborators and Investigators

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

Sponsor

Louis Pasteur Santé Lorraine

Investigators

  • Principal Investigator: Frank WEIN, Louis Pasteur Santé Lorraine

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 (Estimated)

July 1, 2026

Primary Completion (Estimated)

February 1, 2030

Study Completion (Estimated)

February 1, 2030

Study Registration Dates

First Submitted

May 19, 2026

First Submitted That Met QC Criteria

June 9, 2026

First Posted (Actual)

June 11, 2026

Study Record Updates

Last Update Posted (Actual)

June 11, 2026

Last Update Submitted That Met QC Criteria

June 9, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2026-A00152-49

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

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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