Iguanas and Stunted Growth?

[Samba]

I was just wondering if anyone here has ever heard of an iguana's growth being stunted (temporarily or permenantly) due to lack of space. About a year ago I rescued a green iguana approx. 2 and a half yrs. in age and around two feet long, (s2t). His former owner (who also named him 'Iggy", ew), kept this poor thing in a 20 gallon long tank the entire time he had him, never took him outdoors, and only took him out of the tank to clean the cage. (Which, by the way, didn't even have substrate in it). He only fed him pelleted food, which caused MBD (not severe, but it does effect his ability to climb, and walk, since his limbs are deformed). Since I've had Iggy, I've corrected his diet, provided him with near daily outdoor excursions to the park, given him a spacious room to roam and yet, I've noticed very little growth. I fear his growth may be permenantly stunted due to, or in part to being kept in such a confined place for so long. I've also considered that his MBD may also have had an effect. Does anyone have any suggestions or thoughts? It's a shame that such a beautiful animal may remain so tiny for his age, although I'm still holding out hope that he may achieve the weight and length that is normal for an adult iguana. While I'm on the subject, I was watching Animal Planet a few weeks ago and saw the show 'PetsBurg' which featured a 6 year old iguana about the same length/weight as mine. (This was what got me thinking). Anyways, Iggy makes a wonderful educational animal and is very personable, which is why I've decided to keep him, rather than adopt him out so no matter what I'll always do what is best for him. If anyone has information or comments about iguanas being stunted, please let me know.

P.S. His vet said he should've started growing by now... but I just wanted the imput of other keepers...