I learned a little about this topic recently after a bad knee injury from running [torn meniscus] --
Blood supply does have a lot to do with healing-or-not -- taking the meniscus as an example, about 30% of the meniscus has a blood supply, the rest does not, so that if the injured part is of that 30%, it can actually heal, whereas if not, they can only clean it up and stitch it together like a rag doll ---
[for the curious : I got lucky and my injury healed tolerably well on its own sans surgery]
Blood supply does have a lot to do with healing-or-not -- taking the meniscus as an example, about 30% of the meniscus has a blood supply, the rest does not, so that if the injured part is of that 30%, it can actually heal, whereas if not, they can only clean it up and stitch it together like a rag doll ---
[for the curious : I got lucky and my injury healed tolerably well on its own sans surgery]