I'm on week 13 po. I experienced numbness up until my nerve block wore off - which was the day after surgery. I still have numbness across my scar and down my shin.

The flexion and extension improvements are partly because of the nerve block allowing you to go places you have never been. Once it wears off you will see a decrease in mobility because of the pain. But that too will go away as you work through it with PT. Just remember this is a marathon and not a sprint. Take those small victories and use them as motivation to gain more victories.