Agressive Stretching with mechanical assistance

[Nemesis]

I belong to a very expansive gym (expensive :()  In the gym there are 2 machines.  One allows me to work knee to the chest and rear extention and the other helps me stretch the rear hamstrings while stretching the opposite sides front hip joint.  The machines allow me to get a GREAT stretch as I can lock a position in and push on from the locked position. 

I have been keeping records on my progress and have been improving. 

My question is should I be concerned with a femoral head fracture at 4 weeks with this type of stretching?  I should note that all positions are achieved slowly not balistically.

[Lopsided]

My question is should I be concerned with a femoral head fracture at 4 weeks with this type of stretching?

Possibly. If you are not sure then don't. Stick to your PT that you were given and do lots of walking.