Cartilage is a pretty incredible substance. It’s strong yet flexible enough to allow adults’ bones to move against each other without injury for decades.
But in the process of protecting the bones, the cartilage itself can take a beating and become damaged. Worse, once we’re adults, our articular cartilage cannot regrow or heal because it doesn’t have any blood vessels, which means oxygenated red blood cells can’t reach the damaged tissue.
However, experts have discovered some ways to regenerate or repair damaged cartilage. They can even transplant small portions of it.
Although these methods could apply to almost any joint with articular cartilage, they are most frequently used for the knee joint.
Also keep in mind that efforts to restore or regenerate the cartilage work best for younger patients with minor cartilage injuries that are relatively recent. Repair, regeneration, and transplant treatments are not recommended for anyone with longtime or extensive cartilage damage from osteoarthritis.
If cartilage is torn or frayed, doctors can sometimes use a minimally-invasive technique to shape or sculpt the cartilage with special tools in order to minimize joint friction (chondroplasty), and then clear away any loose bits by flushing out the joint (debridement).
Although articular cartilage is not capable of regrowing or healing itself, the bone tissue underneath it can. By making small cuts and abrasions to the bone underneath the area of damaged cartilage, doctors stimulate new growth. In some cases, the damaged cartilage is cleared away completely to do this procedure.
The knee’s meniscus is also made of cartilage, but it can’t be regenerated like articular cartilage can.
Transplant options for cartilage aim to take small plugs of healthy cartilage and implant them into the damaged area. Depending on the size and location of the damaged cartilage, these plugs can be used individually or in conjunction with a few others. The healthy cartilage may come from a non-weight-bearing section of the patient’s knee or from a cadaver.
There’s also transplant options that involve extracting cartilage, culturing it to grow in a lab, then implanting it into the knee. One study found the cartilage of the nasal septum may be especially useful for this type of transplant. 1 "Nasal chondrocyte-based engineered autologous cartilage tissue for repair of articular cartilage defects: an observational first-in-human trial." Lancet. 2016 Oct 22;388(10055):1985-1994. doi: 10.1016/S0140-6736(16)31658-0.
PRP and stem cell therapy
All of the above methods for cartilage repair not ideal, in that they have a limited list of potential candidates. Even then, results are mixed.
But two options that are showing promise for successful treatment of cartilage injuries are platelet-rich plasma (PRP) and stem cell therapies. These therapies to use the body’s own immune system to prompt cartilage to heal and regrow itself in a way it might not otherwise do.
Both stem cells and platelets are components in our body that trigger regeneration and healing in the body. If these elements can be harnessed, concentrated, and delivered to the damaged tissue, they might cause the cartilage to regrow.
Scientists are still working on the best techniques for using PRP and stem cells—not to mention collecting evidence that proves the therapies are effective—but the potential to develop and perfect these therapies is great.