The Paley Institute has a nifty "anti-gravity" treadmill (AlterG) that lets you walk even if you can't weight bear. This is useful even for STRYDE patients, who need crutches in the first few weeks, so I thought I'd write about it.
Basically the machine is a treadmill with an air balloon on top. It lifts you by the groin (like a harness) using a sort of skirt which you wear and ends up being the cap the balloon. That takes off X pounds from your weight, so you can walk safely on the treadmill while respecting the weight limits of the nails.
Today I was still recovering from a very stiff left knee that I had been working on for the whole week. I couldn't fully extend the knee, and PT helped, but not completely. After 10 minutes of walking in the machine (which was painful on the left leg), I could fully extend the knee! This was way better than the NuStep machines, or the PTs. Mike, the strongest and one of the best PTs at the Paley Institute, confirmed that my knee was a lot looser after using the AlterG machine (for about 10 minutes) than after the same period of using the NuStep.
Ask your PT to get you on the anti-gravity treadmill. Walking is the best PT.