Hi,
these days, DVTs are rather well treated and any loss of power due to misuse should be temporarily only. Certainly, a year after a DVT, there should not be any weakness as severe, as you have described it.
So, I start wondering whether there could be anything else going on. For example, she could have injured the nerve or suffered from a Cocaine induced stroke.

But to make any further comments, it would be helpful if you give us the findings of your neurological testing on this patient. E.g.
- history (was the weakness spontaneous and has not changed since onset, has it progressively got worse, has it improved at all),
- reflexes,
- muscle power in more detail (i.e. does the pattern indicate a central or peripheral origin = does the weakness follow any nerve distribution; how's the foot, how about abdominals, etc.),
- any medical testing (e.g. biopsies, conduction studies, etc.),
- muscle tone,
- sensation,
- medication.

Hope this helps a little,
regards,
Fyzzio