Science Fact: Osteoarthritis, the most common form of arthritis, is also the leading cause of disability in the United States, followed closely by back or spine problems. More than one in five U.S. adults suffer from disability, a number that leaps to over 50% for adults 65 and older.
Cartilage is a flexible connective tissue found throughout our bodies, most prominently in the nose and ears. Today our interest in cartilage arises from its use in the body to separate bones, specifically in joints and in the spine.
Joints: Cartilage separates the bones in joints such as knees and hips; it not only cushions the separation, but produces a lubricating protein, appropriately called lubricin, that reduces friction. When the cartilage wears out, bone contacts bone and the likely result is debilitating pain leading to knee or hip replacement.
Spine: Cartilage also makes up the discs that separate the vertebrae of our spines; degeneration of these discs is a major cause of back pain, particularly in older people. Although artificial replacements for spinal discs can be surgically implanted, the procedure has attracted controversy and the procedure is still considered experimental in the U.S.
Given the importance of cartilage and its propensity to wear out, it’s not surprising that there’s considerable research into producing an artificial cartilage that can replace or even improve on the natural substance. The principal driver of this research is osteoarthritis, perhaps because joint cartilage has a simpler structure, is easier to access, and poses less risk of nerve damage than working with spinal discs. Moreover, there’s strong hope that by replacing cartilage when it begins to wear out, the more drastic step of replacing the entire joint can be avoided.
Three different paths are converging today, with the promise of genuine help for osteoarthritis in the foreseeable future:
– Lubrication: Teflon was tried as a lubricant but it turned out to leave debris in the joints that led to inflammation and bone wear. More recent work uses nanotechnology, specifically engineered polymers described as “molecular brushes”.
– Supporting Lattice: Combinations of polymers can be woven three-dimensionally into structures that could retain their shape under the high stresses experienced in knee and hip joints. Most recently, researchers have been using 3-D printers to weave together polymers and cartilage cells.
– Flexible Strength: Hydrogels are polymers containing a high percentage of water, somewhat resembling Jell-O. They are being used in artificial cartilage research to provide flexibility and toughness.
The media have reported some promising new work from Duke University. The researchers are infusing a woven structure with specially designed hydrogels and have produced physical properties close to or better than natural cartilage. The durability of these new structures needs to be proven, but they may well form the basis for an osteoarthritis treatment that can postpone joint replacement or even make it unnecessary.
Science Speculation: Once again, the word of the day is interdisciplinary. Our bodies are so miraculously constructed that our best efforts to repair and replace its parts will seem hopelessly backward just a few years from now. The work at Duke involved five researchers associated with the Departments of Mechanical Engineering & Materials Science and the Department of Orthopaedic Surgery in Biomedical Engineering. When the sufferings of osteoarthritis and disc degeneration are alleviated – and today it looks more like “when” rather than “if” – it’s likely to come from sophisticated and creative teamwork between biomedicine, engineered materials, nanotechnology and composite materials. Moreover, before a complete solution is in sight, molecular biology and stem cell research may also participate.
Has modern technology helped you or someone you know who has osteoarthritis?
Drawing Credit: adapted from evilestmark & Viscious-Speed, on openclipart.org
Comment submitted 3/13/17 by Simon Sargent: I’m 50 now. I’ve been suffering from osteoarthritis since I was 18. Many doctors over the years have said I had knees of a 80 year old. I’ve been waiting so long for technology to catch up and now it finally seems to be happening. It actually brought tears to my eyes when I was watching the news and the story being told of a new break through for people like me. I have not worked since I was 42. The physical pain is constant and unbearable, the depression caused by my osteoarthritis has been a nightmare. I would certainly be the ginny-pig for this new solution. Finally I feel like there is hope to reclaim my life…..Sign me up! Sincerely Simon
Simon, I sincerely hope that the advances in synthetic cartilage come quickly for you and others who are suffering so. I join the other readers in wishing you health and healing – Art Chester
Very good Art. I was going to have a new stainless steel knee joint last October, but in the pre-med inspection I saw the size of the metal joint in a display cabinet and it is huge so that a very large lump of leg bone above and below the knee is removed.
I had not realised previously how large apiece of steel would be spliced in and since I can still walk a mile or two without too much difficulty (although cycling is not so easy)and since there were others in the ward who could hardly walk, I though I would leave things a while and have it done next year, and hope the technology improves a little meanwhile.
I take comfort from the “when and not if” surmise but anticipate the when will be a decade or two away yet, miserabile narru subjectively.