My 13 yo dd has Ankylosing Spond. In other words, chronic arthr. in her lower spine and many other joints. A rare and terrible thing for a young girl to have to deal with, truly.
At first, we thought it was growing pains, this type of arthritis is often missed because people assume it is gp. Her intermitent pains would come and go for about six months to year. Her main complaint were her hips, ankles and wrists. The pains became worse and we noticed that
nothing helped ease her pain, not Ibuprfn or Acetmfn. Warm baths helped the most.
The day we knew something was seriously wrong was when she couldn't walk or bend her back without extreme pain. Her hips, knees, ankles and each joint in her foot was seriously inflamed. She had to have help that morning getting off the school bus, I got a call immediately. Very frightening stuff. By that evening she could walk but barely, but she couldn't move her fingers much, eventually her jaw joints were so stiff she could hardly move them. We saw her ped. that same day and she said, "connective tissues for sure, either arthr. or lupus.", all blood work was clear! Her ped. did everything she could to help us but it still took a month to get her to Houston's med. center for a specialist. By that first visit, she was walking and functioning, but it wasn't easy for her. She walked stiffly, (like the gingerbread man on Shrek). We got diagnosed that first visit to the rheumatologist, also very rare! What confused me was that she didn't complain about her back much, other areas seemed to be in much worse shape.
Here is another big clue that it was something other than growing pains ...
she hadn't grown in over a years time. So, it certainly wasn't growing pains. Not uncommon when kids have chronic inflamation/arthritis.
While hips generally are the first place kids and adults with this disease complain about, it is usually not in conjuction to a growth spurt, it's from sitting in a hard chair, bouncy BUS RIDES, long car rides, bleachers and so on. My niece also has arthr.(dif. sub-type). She was 11 when diagnosed, it must run in our family. She hadn't grown in so long that we were wondering if she might be a little person. Tiny, at least a head shorter than class mates, her little hands and feet were minatures! Zoe never complained of aches and pains. An orthodontist found it when they did x-rays! She's had it so long that she doesn't have regular pain responses. She started meds and started growing! In about years time she has grown at least 5 to 6 inches taller than she was. Amazing!
Mom, it does NOT sound like he has arthritis to me! Esp. if he is growing like that! FOUR INCHES! I didn't know it was possible to grow that much in such short amount of time! He sure does sound healthy!

That's a lot of boy to feed, enjoy and celebrate four inches!
Here is the website to the Spondilitis foundation if you still have concerns.
http://spondylitis.org/about/as.aspx
Lainie