Be very sure to take the drug Fosamax and not the infusions. The infusions are extremely painful during and afterwards for several days. I took 3 infusions of 90 of Aredia last year and thought I would not survive the first day each time.

Hi Jonsmom! I can only imagine the anguish you are going through with your son. Mine has JRA and it kills me to see him limp or have trouble.
I have a benign bone tumor disease called angiomatosis of the bones that affect several bones throughout. The weight bearing bones are of course the worst.
My doctor at NIH (I go every year there) suggested the infusions of Aredia (a bisphosphate drug similar to Fosamax) to help build the bone back. Although I have had a donor bone graft to one area, this was scheduled for all the bones where I am losing good bone.
I went through 3 infusions (one every 3 months) - was supposed to have them for a year and then be re-scanned. I couldn't handle getting the 4th one since the first three put me on my back for 1-2 days in severe pain. Let me state that ALL my bones hurt - not just the ones with tumors. I'm talking even my fingers and toes hurt. It was actually worse than the day of any of my surgeries. Well also - you get morphine in the hospital and I had only hydrocodone at home too. But I wouldn't put my son through that unless I KNEW the results would be worth it and still it would be a very hard decision. My scan showed no improvement after the infusions which just made it all the worse. To suffer for no improvements. But it was worth a shot - it was attempt that or face total joint replacements. I still haven't faced that yet - thank god!
But it may be different with different tumors (such as UBCs). But I would definately go somewhere that has done the infusions before. I think some of my issues resulted from the infusions going in too fast. You should only have 30mg an hour. I had all 90mg within 1.5 hours the first time. Also - Fosamax comes in a drug form and is something to consider.
Also - you might want to look into NIH, Duke, John Hopkins, Shriners, or one like them. They have wonderful doctors there that sometimes make a HUGE difference in your surgery outcome. Our local doctors (even a close research hospital - UT) had never heard of my diagnosis. You are the best advocate for your son - keep up the great work of checking things out (even online) to find help!
Wishing you all my best!