What is meant by radial distortion?
Look at these pictures of the BA777 crash at LHR.
www.flightglobal.com
As you can see from the first picture the first stage turbine blades are sheared off at around half of the length of their radius. This was because they were rotating at some speed when the impact occurred. The engine nacelle was forced onto the rotating blades causing almost identical damage to all the blades as they turned and they have all fractured at a similar radial length. The engine therefore must have been rotating and producing at least some thrust on impact.
Look now at the second image of the other engine and you will see that the turbine blades are all intact even though the nacelle has hit the ground quite hard and scooped in a lot of dirt in the process. This engine was not rotating at impact and therefore could not have been producing any thrust.
As is also witnessed by the BA incident, a total loss of thrust below 1000' can be brought so a safe outcome given favourable terrain.