You learn fast in fell running, it has a tendancy to highlight biomechanical imperfections in you and bring them to the forefront. I was a strong trail runner, hiker and cyclist when i made the transition to fells but almost immediately found out i had Illiotibial Band Syndrome laying dormant in me. I'm 9 months into Physio and it's not showing any signs of shifting, my prognosis is now a matter of years not months. If i had recognised the symptoms it might have been easier to combat, but my best advice to you from experience would be to watch out for potentially chronic injury finding you and be prepared to pay for the help/opinions of professionals.
Anyway that's my weekly whine out of the way so welcome along and don't take any chances with your knee recovery.
Can't climb for toffee...