My gecko has stiff rear limbs

Question
QUESTION: My leopard gecko is about 10 years old and was recently given to me by a friend. He has always been well taken care of, fed properly and given calcium powder. When I first got him here with me his previous owner told me he had a bit of a swollen rear leg. I'm not sure if the swelling went away, but I started to notice that my gecko never really straightens out, as if he's always bent around, and he drags his hind legs a lot. I examined him to see if he has any movement in his hind legs, and he does seem to individually, but when he walks around he just drags his hind legs and tail behind him. The fact that he's a bit crooked doesn't help him much either. He doesn't seem in pain, he sheds and eats regularly and is very friendly and curious. Any ideas what could be wrong with him? He's not impacted as there is always fresh poop in the cage, and there's nowhere for him to climb up in the cage and fall down and hurt himself.

ANSWER: Hello Angel,

Wow, that is great, 10 years old.  
It sounds like he might have a touch of metabolic bone disease possibly.  Has he ever had any UVB exposure at all in his lifetime?  
How often has he had calcium supplementation?  
Do you have any pictures of him?
Do you keep him on sand, or paper towels?
What foods do you feed him currently?

Tracie

---------- FOLLOW-UP ----------

QUESTION: Thanks for getting back to me! I'm not sure about the UVB exposure, he has a light in his cage that gets turned on, the bulb is one for reptiles from a pet store I think. He gets the calcium every feeding, it's in powder form, and I'm sure he has been getting it most of his life. I'm feeding him meal worms, that's what he has been getting for a while now, and I'm pretty sure his bedding is crushed walnut. He is not impacted, I checked him thoroughly as I just lost a gecko to impaction and mbd a few months back. My gecko poops on a regular basis and has a good appetite. He also has a little sauna in his cage that he likes to spend time in. I noticed his joint in his rear leg is still swollen, and the movement in his hind legs is very stiff and limited. I do not have a picture right now of him, but I could get one if that would help?  

Answer
Hello Angel,

Well, if you are positive that he is not impacted, then, it will most likely be calcium related perhaps.  Unless he is having some other type of issue such as kidney or liver.
Some pictures would be great, if you can get them.  Thanks.
Do you feed him in a small feeding dish or on his walnut bedding?  
Could he have injured himself possibly?
It is possible that it could be calcium related.  There is not a lot of research unfortunately, with reference to UVB use for geckos.  However, I do think that even reptiles who require low levels of UVB still should be exposed to UVB lighting for optimal health.  They can only sustain their calcium levels for so long until the levels begin to fall.  
The UVB exposure allows for D3 synthesis & without this, over time, their calcium levels will fall.  They cannot properly absorb their calcium without "some" UVB exposure.
Try getting the Zoomed Reptisun 10 fluorescent tube bulb.  Here is a link to where you can purchase it from for a great price.  They are having a sale on them right now, too.  
http://www.petmountain.com/product/reptile-fluorescent-bulbs/11442-504983/zoo-me

Let me know how he is doing.

Tracie