Internal scar tissue, as in lesions (fibrous, stringy cords of scar tissue between muscle and deeper layers of skin and/or other structurals) from healing from inside, can interfere with range of motion depending on how extensive they are and how involved the surrounding tissues might be. This might present in stiffness, since the range of motion could be interrupted. Stumbling could also be a result of internal lesions.
Probably wouldn’t hurt to have a chat with your vet?
Sure there's right and wrong but mostly there's just a whole lotta different.