programdude, really sorry about your situation and having to deal with this LL complication so far after your original surgery and months after nail removal. completely agree that it's not his fault since he was following his doctor's recommendations completely. my guess is that the femur may have already been fractured from some activity based on the pain he had prior to the stretch that completely broke it. a similar thing happened to the guy that did quadrilateral lengthening with paley in the old forum. he had a stress fracture in his tibia months after the nail removal.
his exact words "Again, the femurs hardened really fast, and I was walking again in January, 2015, but when I started running (March), the femurs where fine, but I had a stress fracture of the left tibia. Admittedly, I was running really hard on the trail, rough terrain, but still, I was surprised they weren't completely solid by then. It probably has something to do with the bones needing to be loaded, stressed, in order to fully consolidate, and with the rods in place in the tibias, even though I was lifting and running, the rods were protecting the tibial from the stress, and I had to stress them with the rods out (and pushed it a touch too far) for them to fully consolidate."
anyways what's done is done. wishing you the best programdude- I know you'll make it through this man. please do let us know though if you ever figure out the cause and maybe how it could have been prevented.