Anyone ever have a knee injury and have their quad basically atrophy to non existence?

11 months post op Micro fracture and my left leg is WEEeeeeAK, even after tons of PT. (I still may have something wrong, MRI next month)

I just got this device and gonna give it a try. Wondering if anyone has worked with Stim for muscle growth/training?

http://www.shop-orthopedics.com/kneehab_xp_electrotherapy_unit_p/0412-50...

Any tips/help is appreciated.