Self admitted, I really don't know all the intricacies on AAS. From what I have read is that there is new collagen being laid down in response to things like winstrol or anavar, but it is potentially more brittle than normal collagen.
There appears to be more research on increasing collagen production with consumption of collagen peptides and Vitamin c (and to a lesser extent Vitamin D). I think the amount on collagen is 30gm a day and Vitamin C is like 2 - 3000mg per day. That was the recommendation from the surgeon when I had my rotator repair in 2017.
Overall, the best bet is still going to be active therapy. Simply doing leg extensions or light leg press isn't the way to go. It should be from BOTH sides of the quad. Its a hip flexor as well as a lower leg extender. So, thinking globally, if you have issues with your "hip" that could have put the other side of the muscle at risk