New Surgical Technique Combines Fat Tissue With Collagen Membrane for Knee Cartilage Repair

Cartilage Damage Can Lead to Early Arthritis if Untreated

Focal cartilage defects in the knee cause pain, reduced function, and lower quality of life. These injuries have limited ability to heal on their own. Without treatment, they can lead to premature osteoarthritis. Many surgical approaches have been tried over the years. However, most show disappointing results over the long term.

Researchers Describe a New Approach Using Your Own Fat

A team of orthopedic surgeons from Brazil has developed a new surgical technique. It combines two promising treatments: micro-fragmented adipose tissue (specially processed fat from your own body) and a collagen membrane. This combination aims to repair focal cartilage defects in the knee without some drawbacks of older methods.

The technique uses the Lipogems® system to process fat tissue. This creates a product rich in mesenchymal stem cells (regenerative cells that can develop into cartilage). Unlike bone marrow procedures, harvesting fat tissue is minimally invasive and readily available.

The Procedure Avoids Damaging the Bone Beneath Cartilage

One key advantage of this technique is what it does not do. Older methods like microfracture deliberately create small holes in the bone. This releases bone marrow cells to help healing. However, studies show this approach often leads to problems. Up to 60 percent of patients develop bone overgrowth within the repaired area after two years.

The new technique carefully prepares the cartilage defect without penetrating the underlying bone. This may reduce the risk of bone-related complications while still providing regenerative cells through the fat tissue graft.

How the Surgery Works: A Step-by-Step Overview

The procedure involves several coordinated steps:

• Fat collection: About 20 milliliters of fat tissue is harvested from the inner thigh. A special solution provides local anesthesia and helps with collection.

• Fat processing: The Lipogems® device processes the fat in about 10 to 15 minutes. It uses gentle mechanical forces—no enzymes or chemicals. The process removes inflammatory substances and blood cells while preserving the helpful regenerative cells.

• Cartilage preparation: The surgeon cleans and shapes the cartilage defect. The edges are made smooth and vertical. Importantly, the bone beneath is left intact.

• Membrane placement: A collagen membrane is cut to match the exact shape of the defect. The processed fat tissue is applied to the membrane's rough surface. The membrane is then secured over the defect with fine stitches.

• Final filling: More processed fat tissue is injected beneath the membrane. Fibrin glue seals the edges. The surgeon tests knee movement to confirm everything is stable.

Fat Tissue Offers Practical Advantages as a Cell Source

Mesenchymal stem cells can come from several sources in the body. Bone marrow and blood are common options. However, fat tissue offers unique benefits:

• It is widely available in most patients

• Collection is minimally invasive

• Processing can happen during the same surgery

• Fat contains abundant regenerative cells called pericytes (helper cells that support healing)

The Lipogems® processing keeps the tissue's natural structure intact. This may help the cells survive and function better after placement.

What This Means for Patients Considering Treatment

This publication describes a surgical technique rather than reporting patient outcomes. The authors present this as an "alternative option" for treating focal knee cartilage defects. They base their approach on growing scientific evidence about the regenerative potential of adipose-derived cells.

If you have a focal cartilage defect in your knee, this technique represents one possible treatment path. It combines established surgical principles with newer regenerative medicine concepts. The approach aims to provide regenerative cells while avoiding bone damage that can cause problems later.

Patients interested in this type of treatment should discuss several factors with their surgeon. These include the size and location of their cartilage defect, previous treatments, and overall joint health. As with any newer technique, individual results may vary. Longer-term studies will help clarify how well this approach works over time.

Source: Leal et al., Arthroscopy Techniques, 2024.