can physical therapy be harmful

I am going to p.t. for my back.  The therapist seems not to hear me when I say I am unable and even unwilling to do exercise which I know will cause FURTHER DAMAGE TO A BAD KNEE I have.  I would like to get stronger, better, in my back, but the process seems downright dangerous.  The p.t. is thick as a brick and I cannot seem to get her to understand not to push me into certain exercises; and to understgand that a bad knee I have can be made worse quickly by stressful exercieses.  What do we do?  I am afraid to go back to the session for fear of injury which would make it necessary to have a knee replaced quite soon.  I just had a hip replaced, 2/09, and don't want to go thru another surgery-hospitalization-recovery for a couple of years.
She is terribly insistent and does not remember my requests from one session into the next ones.

Is this common.  What avenues might I take to get the message acress so that I can continue?

[Dr Vinod]

Hi!

This is not at all common. Ignore the Physiotherapist and you have the choice to choose the best.

Ask your Orthopaedician or the surgeon who operated you for advice and for recommending you a good Physiotherapist.

As your Orthopaedician knows about your condition he can co-ordinate a session for you and see if everything is perfect and for you not damaging your knee further.
Do not do any PT in doubt and without knowing the pros and cons.

This should be highly motivating sessions and you should be convinced about them.

Take care!