The planet Uranus is another solar system anomaly, where according to the NASA profile has an axial tilt of 97.8 degrees, also considered to be retrograde. This NASA summary "Uranus" suggests the current theory of a large planet-sized impact earlier in its history.
Does the planet-impact theory still hold true or have new accepted theories come to light?
Most of all, are there any results from any simulations available?
A note, this is posted as a separate question to my other question "What is the current accepted theory as to why Venus has a slow retrograde rotation?" as the axial tilt is significantly different.