Is Cartilage Regeneration an Option for Osteoarthritis?

Research on the Best Techniques for Cartilage Regeneration

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Man experiencing joint pain while on the beach. Jeannot Olivet/ E+/Getty Images

Cartilage regeneration attempts to restore damaged articular (joint) cartilage. Several techniques have been used for cartilage regeneration. While some of these are being used today, researchers continue to look into new ways to regrow cartilage in an attempt to give people relief from the pain of osteoarthritis.

What Is Articular Cartilage?

The matrix of cartilage is comprised of collagens, proteoglycans, and non-collagenous proteins.

While cartilage is a highly-organized structure, about 85 percent of cartilage is water. This decreases to about 70 percent in older people. Chondrocytes are the only cells found in cartilage and these produce and maintain the cartilage matrix.

Articular cartilage serves as the cushion and shock absorber within the joint. It does so because it lines the ends of the two bones that form the joint. Cartilage damage can be caused by several conditions including:

Joints affected by cartilage damage become painful, stiff, and have a limited range of motion.

The problem is that cartilage is unable to heal itself. Consequently, articular cartilage has become the focus of many researchers and tissue engineers who strive to be able to grow new cartilage and transplant it in place of damaged or worn cartilage.

Progress With Cartilage Regeneration

Several techniques have been developed that show progress in cartilage regeneration.

  • Debridement or Abrasion - A surgeon arthroscopically removes loose cartilage which causes bleeding at the bone surface and growth of fibrocartilage (fibrous cartilage or scar tissue). In some cases, the fibrocartilage may not be strong enough to effectively protect the joint.
  • Microfracture - A surgeon arthroscopically clears the affected area and makes several perforations in the bone. This is designed to stimulate bleeding and growth of fibrocartilage as well.
  • Mosaicplasty or Osteochondral Autograft Transplantation Surgery - A surgeon removes a plug of bone with cartilage covering from a healthy area of the joint and transplants it to the damaged area.
  • Periosteal Flap - A surgeon removes a portion of the periosteum (the connective tissue covering all bones) from the shin and transplants it to the area of cartilage damage.
  • Autologous Chondrocyte Implantation (ACI) - A surgeon arthroscopically removes a small portion of cartilage from the knee. The tissue is then sent to a lab to be cultured. A second surgery is required so the lab-grown cells can be implanted at the site of the damaged cartilage.
  • Osteochondral Allografts - A donor's bone is used to repair the damaged cartilage.
  • Matrix Associated Chondrocyte Implantation (MACI) - The FDA approved this procedure in 2017 in use for people under 55 with "focal chondral defects" — lesions that can lead to osteoarthritis of the knee. It is similar to ACI but requires less invasive surgery and the chondrocytes are shipped back to the surgeon on a patch that acts as a scaffold over the damaged area.

All of the procedures yield mixed results. There are still many questions that plague attempts at cartilage regeneration.

More clinical trials are needed to find definitive answers and to develop procedures that relieve arthritis symptoms and produce a durable replacement for damaged cartilage.

The Research Continues

The challenge of coming up with a better solution for cartilage regeneration is on the minds of many researchers. Throughout the world, new research and techniques continue to look into this matter and the early results look promising.

For instance, in 2008, bioengineers at Rice University discovered that intense pressure (comparable to that found over half a mile below the surface of the ocean) stimulates cartilage cells to grow new tissue.

This new tissue possesses nearly all of the properties of natural cartilage.

The researchers believe this development holds promise for arthritis treatment. The lead researcher forewarned that it will be several years before the process would be ready for clinical testing in humans.

Stem cells are also being used to grow new cartilage for arthritic hips in a technique being developed at Washington University School of Medicine as of 2017. In partnership with Cytex Therapeutics, the hope of these researchers is that this will become an alternative to hip replacement surgery.

This technique shows the most promise for those under 50. It uses "3-D, biodegradable synthetic scaffold" and essentially resurfaces the hip joint to ease the pain. For arthritic patients, it may delay, if not eliminate, the need for a new hip.

Sources:

Axtell B. FDA OKs First in a New Generation of Knee Cartilage Repair. Arthritis Foundation. 2017.

Boyd J. Cartilage regeneration '20,000 Leagues Under the Sea'. Rice University. 2008.

Dryden J. Stem Cells Engineered to Grow Cartilage, Fight Inflammation. Washington University School of Medicine. 2016.

Hospital for Special Surgery. Procedures to Repair Damaged Knee Cartilage Show Promise in Treating Patients Over 40. 2016.

Rai V, Dilissio MF, Dietz NE, Agrawal DK. Recent Strategies in Cartilage Repair: A Systematic Review of the Scaffold Development and Tissue Engineering. Journal of Biomedical Materials Research Part A. 2017. doi:10.1002/jbm.a.36087.

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