I too did not have joint issues until old age. I now continue to recommend prolotherapy along with physical therapy later. My terrible back issues got underway after a fall on the ice required a hip fix that left one leg shorter than the other. The SI Joint accommodated that by hyperextending continually and prolotherapy fixed the "lax ligament" that the hyperextension had caused. I did develop a mild scoliosis.
Unfortunately the 3 years it took me to find a fix pushed the other hip out of place and another operation from a DR. who didn't believe the problem and didn't tell me, left me in bad shape with a hip that continually moved around! UGH! The result is the entire spine is now "wiggley".
Another prolotherapy treatment from my regenerative medicine doctor tightened the ligaments of my cervical joints and I am relatively much better.... just out of shape and that is difficult for us oldsters to rebuild. Do check some of this out... National Spine and Pain Centers do this work, among others. It is not yet covered by insurance but worth every penny!