I have a very similar problem because I sprained my ankle badly and elected not to go to PT. Of course, at the time I didn't know I was supposed to stretch it out pretty much right away to regain mobility especially before calcification occurred in the joint. So my left ankle is like minus 10 degrees plantar flexion and dorsiflexion. Very tough to get my knees over my toes very far without the bone on bone grinding like you said Marcus.
Would be interested to hear some ideas for this.