I can’t do squats or deadlifts at all yet. Both motions produce quite a bit of pain in my femurs. I’m hoping that it’s due to the nails still being inside. My leg muscles are back to the pre-surgery thickness so I imagine it’s not a strength issue.
I was in the same boat after femur lengthening for over 1 year after the surgery.
Everything was fine, x-ray, flexibility, but there was still pain around the knee muscles when I bent them for something like split suqats, where you move forward while doing squats. When it got better I overdid it by doing something extreme like running without warm up, and then it got worse again due to light injury.
What ultimately helped and made it so that it feels almost like pre-surgery is
going down stairs (1 stair) and going back up (2 stairs) for several minutes. First with no weights, then 2.5kg in each hand, then 5kg each hand.
Your muscles gradually heat up, and it becomes easier like every 2-3 minutes, and after 10-15 minutes you have done a great deal of training for the weak muscles around the knee that usually hurt. 15 min of that is intense cardio workout, and it is aimed at where you need it the most.
After that you can do any exercise without pain, or you stop at that point. Your muscles will be ready for any exercise that previously hurt. You can do some squats that previously hurt or stretch way better than before. The more you do the better.
You need to do this every day for a few weeks until you don't need warm up for any exercise that hurt right now.