Let’s talk about something that isn’t actually a bone or a joint but is vital to them staying in good working order. That’s your cartilage, a type of connective tissue found throughout the body, often at the ends of or between bones, where it helps protect them from harm.
Some fish have entire skeletons made of cartilage. It is softer than bone but harder than muscle. There are no nerves or blood vessels. It’s pretty hard to damage cartilage, which is pretty resilient, but when it does need repair, it’s a slow and inefficient process. It can’t regenerate like other parts of the body, in part because of the lack of blood flow, so when tissue is lost, it’s hard to replace.
Its lack of nerves means that you can injure your cartilage without even noticing it. You won’t feel any pain. The x-rays that pick up broken bones won’t show your cartilage, damaged or otherwise. That makes cartilage problems hard to diagnose before we even start thinking about treatment.
Doctors and scientists have tried to figure out ways to fix cartilage when it is damaged, from complicated surgical procedures to attempts by biological engineers to grow new cartilage in a lab. These techniques are starting to show promise, but we’re still a long way from being able to restore it to its full glory.
This means you could see a degeneration in cartilage’s many important roles. As a resilient but somewhat elastic surface, cartilage can act as a shock absorber. When it’s found around joints like your knees, it prevents too much harm to them from any hard impacts. It does this while still being relatively frictionless, meaning the joint and your movement can still flow freely.
When cartilage wears away and bones are forced to rub up against each other, that painful experience can be a symptom of osteoarthritis. Then there’s damage from trauma, something that tends to hit your hard-working but vulnerable knees the worst. There’s a type of cartilage called fibrocartilage between your vertebrae in your spine, known as your spinal discs. Knocks, strains and tears there can cause back pain, which then contributes to significant discomfort and mobility issues through the rest of your body.
So when you’re thinking about your bones, spare a thought for the cartilage between them, and hope we find a better way to repair it.