Have you had an x-ray to determine the position of your kneecap? I have a condition called patella baja where scar tissue has pulled my kneecap down and out of place. So it's striking the tibial plateau, and puts a lot of pressure on the damaged spot when my leg is in full extension. I actually can't put weight on it when I'm in full extension--it hurts so much the knee buckles.
Other possibilities include the hardware--did you have the screws removed? If not, there could be a stress fracture, or even just irritated bursae in the area that the hardware is stressing.
Anyway, it's always a good idea to go back to the doctor when you have a new problem--especially since you have had PFS issues in the past.
Heather
