Researchers at Scripps Health have secured $12.7 million in funding to develop a groundbreaking treatment that could repair severe knee cartilage damage without relying on donor tissue or multiple surgeries. The California Institute for Regenerative Medicine (CIRM) grant will support a five-year study on scaffold-free tissue engineering, a technique that grows cartilage and bone in the laboratory using stem cells, then implants the engineered tissue directly into damaged knees .

What Makes This Approach Different From Current Treatments?

Today, patients with large cartilage and bone injuries in the knee face limited options, each with significant drawbacks. The most common surgical approach is an osteochondral allograft transplant, which involves removing damaged cartilage and bone and replacing it with healthy tissue from a deceased donor. The problem: there simply aren't enough donor tissues available, and preserving them is difficult .

Another option uses the patient's own cartilage cells, but this requires two separate surgeries and relies on cells that grow slowly and don't regenerate cartilage effectively. The new stem cell approach being studied at Scripps targets larger injuries, specifically those affecting areas larger than 2 square centimeters, which affect around 900,000 people annually in the United States and result in more than 200,000 surgical procedures each year .

The research builds on earlier work by senior staff scientist Shawn Grogan, who developed a method to generate scaffold-free cartilage and bone tissue in the laboratory. Instead of embedding stem cells into a fiber scaffold (the conventional approach), Grogan's technique creates three-dimensional clusters of cells called spheroids from mesenchymal stem cells, which fuse together to form tissue. When implanted into damaged tissue samples, the lab-grown tissue effectively repaired defects and structurally integrated with the injured areas .

"A biological implant that can successfully treat cartilage and bone defects of the knee would resolve the limited availability of donor graft tissue and has the potential to delay and eventually eliminate the need for joint replacement," said Dr. Darryl D'Lima, director of orthopedic research at Scripps Health and the study's lead investigator.

Dr. Darryl D'Lima, Director of Orthopedic Research at Scripps Health

Why Does Scaffold-Free Technology Matter?

The scaffold-free approach offers a significant advantage over traditional methods. Conventional tissue engineering embeds transformed stem cells into a fiber scaffold, but these scaffolds often don't integrate well with the surrounding tissue and can cause compatibility issues. Scaffold-free tissue more closely mimics cells in developing native tissue, which means it has a much higher potential for healing and seamless integration with the injured area .

How Will Researchers Test This Technology?

The five-year grant will fund laboratory-based tissue engineering and cartilage and bone injury repair surgeries in animal models. Researchers at the Shiley Center for Orthopaedic Research and Education (SCORE) at Scripps Clinic aim to demonstrate that surgically implanting the engineered, scaffold-free tissue is both safe and effective. At the end of the grant period, the team plans to submit a new drug or biological product application to the Food and Drug Administration (FDA). If approved, this could lead to clinical trials in humans, potentially bringing the treatment to patients within the next several years .

• Current Timeline: The five-year grant period will focus on animal studies and safety validation before human trials can begin.
• Regulatory Path: Researchers will submit an FDA application for approval as a new biological product, a process that typically takes several years.
• Patient Impact: If successful, the treatment could delay or eliminate the need for knee replacement surgery in thousands of patients annually.
• Broader Applications: While the current funding targets knee injuries, the same technique could eventually be used to treat cartilage and bone damage in other joints, including the ankle, elbow, shoulder, and hip.

The significance of this research extends beyond the knee. Cartilage injuries in these joints can be precursors to osteoarthritis, a widespread joint disease that affects millions of people. By developing a way to repair cartilage damage early, researchers may be able to prevent or slow the progression of osteoarthritis before it becomes a chronic condition requiring joint replacement .

For patients currently dealing with severe knee injuries, this development offers genuine hope. Rather than facing a choice between limited donor tissue availability, multiple surgeries, or eventual joint replacement, they may soon have access to a treatment that uses their own biology to repair damage more effectively. The next five years of research will be critical in determining whether this laboratory success can translate into a safe and effective treatment for patients.