Total joint replacement was my medical specialty. There have been several acute diseases that have been "cured" through the use of Vaccines, and Antibiotics. An interesting anecdote that I heard once. It was not until World War II that you had a better than 50/50 chance of medical improvement by seeking medical advice. It was penicillin that made that happen. Disease disappearance has prompted people to back off of some vaccinations, and we are seeing re-appearance of measles. I truly hope that we got rid of smallpox and polio though. Even "the plague" and syphilis, another couple of early scourges of civilization are very amenable to treatment with antibiotics.
From my specialty, the mechanical and biological changes of the bones, cartilages, and ligaments during the arthritic process is very severe by the time one submits to getting a joint replacement. There are no stem cells to inject that can instruct the bone to restructure to normal shape and consistency. Cartilage can be regrown slowly, and we can do "spot" repairs of articular cartilage after injuries, as we can replace the meniscus after acute injury, where the rest of the knee is still normal. They are even 3-D printing the collagen scaffolding of a meniscus and putting the patient's own stem cells into this scaffolding before implantation. (still mostly in research I think) This research continues apace.
Current science still offers artificial total joint replacement for end stage arthritis, that has improved greatly since the '60s, when it started. And, over time, the costs did fall. My reimbursement (purchasing value received) for a total hip replacement fell 75% over the first 25 years of my practice. If fell low enough to drive total joint patients to specialists, and the casual joint surgeon found more lucrative things to do. I know of several of my patients whose artificial joints lasted 30 years. Many more than the 10 years or so that was the common number back then to tell a patient. We also started putting total joints in younger patients. My anecdote was the 50 year old man with knee arthritis from an injury in his early life. With severe arthritis, he might have been told to wait until he was 65 to get surgery. However, that 50 year old was in the prime of his life and career, and was being asked to give that up. We started doing the surgery at age 50, get them through life. The patient had to understand that they would need a revision sometime down the line. I can't count the number of times I heard "Thanks Doc, you gave me my life back." Of course many times that came from a retired individual that was able to get back to golf with friends.
On the other hand, I had my ACL replaced in 1992, and my knee survived 4 marathons, and several small triathlons. Sure, I have some mild arthritis now, and don't run anymore, but that is because I lost my medial meniscus in 1990, back when they did not have the ability to repair or replace a meniscus. So there has been a lot of improvement over my lifetime.
Now the chronic disease epidemic, currently not cured, is another cesspool that I will not address. That is a much too political a topic for me to want to address. But I know at least some of the successes of modern medicine.
