If I get some free time today, I’d like to research leg extension surgery. As I understand it, the tibia (but not the fibula?) is broken, and some sort of splint is applied. I believe the splint anchors to bone on both sides of the break, and there’s a screw-like mechanism that is adjusted, I believe daily, to advance the distance between the two broken segments of the tibia.
This is a good example of how connective tissue (here, bone) can be grown. Since this is a medical procedure conducted and approved by MDs, one would think the process has been well studied and documented, and that it is designed to achieve “healthy” healing.
In some ways, this process may be analogous to PE (especially hanging). Establishing microtears is like fracturing the bone. Repeating a PE workout may be like advancing the “screw.”
Of course, bone is not the same as ligaments and fascia, so the analogy will only go so far.