Hello, it’s not that uncommon to have a bony avulsion fragment from the fibula, like in your ankle. It’s still controversial what’s the best thing to do with the fragment, and this can vary from removal to leaving it alone and just focusing on repairing the ligament. When there’s not enough good quality tissue to work with, yes an augmentation is useful. This can be in the form of a tendon, or a synthetic internal brace device has also become quite popular. How “common” it is to have inadequate tissues can be quite subjective depending on the judgement of the surgeon but usually it is better to augment the repair when in doubt.