doughmint...
I also cycle quite a bit and look forward to getting back to it quickly. I have not stopped riding but flipping my bike two weeks ago almost did me in! My date is in 2 weeks. Just curious as to how much you can cycle after 4 weeks? Are you on a trainer, on the street...? As far as the knee, are you still seeing a physical therapist? I periodically have pain in my knee related to my hip. Pat may be right about this being related to the surgery. Further, if you are like me, I externally rotate my entire leg to compensate [by as much as @ 15 degrees or so]. After surgery, the change to a more normal alignment [and gait] may be a contributing factor.
We should get all the resurfacing cyclists to meet and do a ridculous ride - like a Mount Washington in NH! Soounds like you are doing great... best wishes for a speedy recovery.