I usually refer people to the website of Dr.Mark Johnson ... He has good explanations ... http://www.prolotherapynashville.com. I found a paper he wrote and it can be found at ...
https://journalofprolotherapy.com/prolotherapy-connective-tissue-damage-syndrome-why-am-i-hurting-and-no-one-seems-to-know-what-is-wrong/#:~:text=The%20results%20of%20Prolotherapy%20treatment%20in%20patients%20with,underlying%20cause%20%28ligament%20damage%29%2C%20and%20secondary%20degenerative%20effects.
The idea is that the ligaments that are stretched and not able to do their job. The treatment provokes them into healing themselves by being poked with a needle filled with a solution ... like sugar water. The poking is done with a machine view of the ligament. My treatments poked the length of the ligament, and my fix took 10 days. I awoke in the middle of the night to feel the ligament actually snap back like a rubber band. My Dr. did say that was an unusual experience. Others have had their 'fix' without the 'snap back' experience.

Do check it out. I do not understand why the process is still considered 'alternative', except that ligaments have gotten lost with the increased ability of surgeries and replacements .... as Dr. Johnson's article says.