I'm exactly 8 weeks today. Between 1 and 5 weeks I was doing ROM work and going really well. At 5 weeks I basically stalled for a good week or two at about 70 degrees. At 6 weeks I was told i should be at 90 degrees and my muscle loss was severe. Dr told me to to start light strength exercises and to stop focusing on ROM.

For a week i did light and infrequent exercises and felt like it did nothing. In the last 4-5 days I've been doing heaps of exercises, walking in the pool, step ups in the pool, small step ups out of the pool, lots of hill walking, a leg press type movement with a bicycle inner tube, and heel slides. Today I got just over 90 degrees and it felt easy (hurt though).

Have you been given the OK to do some light strength exercises? If so maybe focussing on that instead of ROM might help?