At 3 to 4 feet tall and over 75 lbs, they can certainly do damage above the ankle, and a little dog is no match.
I've seen the scars on a human (a former boss of mine) from a javelina attack. It was just below his knee.
It was a serious injury.
I cannot imagine that you are talking about the javelinas as we have here...they are not anywhere near that big. They are not a foot tall. Sounds like you are talking about wild hogs. They can...and do..kill people. They are huge. Javelinas are tiny.