There is actually a post in this section about a broken leg on a leopard geck that you may want to read.
However I actually had a gecko that I rescued from Petco with a broken leg and it does just that it just kind of collapses and flips over, really horrific looking. Definately get ontop of hte whole calcium thing. I actually had to give my leo liquid calcium 2 x a day so if you do make it to the vet you may want to ask for that.
ALso the way that he treated the leg was just a make shift cast with a piece of cloth medical tape. I did have to keep an eye on it and make sure that it stayed in the correct position but she did recover. In fact she is doing quite well, she does still have some problems with that leg I do notice but I don't think there is much more that could be done for it. Here is a picture of my little gigi with her splint, sorry it is so blurry but you can also see how pale she was from the lake of calcium, she not only had the broken leg, she had some broken ribs and the rest of her bones were translucent so she was too. Good luck and keep us posted.
Christina

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1.1 Russian Tortoise (Willy & Mikey)
0.1 Ornate Box Turtle (Lily)
1.0 Red Eared Slider (Chester)
0.0.2 White's Tree Frog (Kermit & Phil)
0.0.1 Red eyed Tree Frog (Justin)
0.0.2 Big Eyed Tree Frog
0.0.2 Bubbling Frog
0.0.2 Tiger Leg Tree Frogs (Akari & Shiro)
0.0.3 Amazonian Milky Tree Frogs
0.0.1 Dwarf Megophrys
0.0.2 Rainbow Burrowing Frog/Ornate Hopper
0.0.3 Asian Blue Webbed Gliding Tree Frogs
0.1 Praire Dog (Timmy)
0.2 Chinchillas (Layla & Snickers)
0.4 mice (Gabby and friends)
0.1 dog (Holly)
2.0 Cats (Champ & Bear)
Oh and a husband 