Hypothetical questions have problems because they’re not specific enough to the situation. So, a few things I’d need to know would be: how many children, what kind of abuse (since that would vary how much treatment and therapy the children would need), the ages of the children, who is abusing them, why are they being abused (mental illness in the abuser? abuser was abused?), etc.
The younger the children are, and the longer the abuse has been doing on, the more likely the children will have lasting psychological damage. This would create a difficult situation for whoever takes on the task of raising the children. If the children are abused by their parents, that will add more damage. If the children are abused sexually by a family member, that would create the most damage.
Considering all of that, I don’t think I could adopt them. I am not in a place in my life where I could raise children (and I am not entirely sure I will ever be there). This is especially true if the children have extra issues, and need extra care. I would rather let someone more capable to adopt them so they can get the care they need.
If the question is exclusively I adopt them or they continue being abused, well, I have a hard time imagining that since that situation would be extremely unlikely to occur. If it did magically occur, it’s something I would have to decide when the time comes.