Cat limping. Help!

I have two 3-year old cats. Both have had no previous health issues, both are female, declawed and under 9 pounds. One of them has been limping a favoring a front leg for about six months now. Both of my cats have always made a funny sound when they jump up and down from things so I cannot tell if she is in pain when she lands.
   
I have felt around to see if she has any painful reactions to me squeezing from her paw to her shoulder and she does not react. I took her to the vet about two months ago and he thought she had strained something and gave her a shot of a steroid. She did not react well to the steroids (sick, lethargic, depressed, etc.) although her limp improved slightly. After the shot wore off, about a month later, I took her back in. She has popping in her right wrist area which I can heard every time she curls her front paws under to lay down. My vet was concerned she had arthritis.
   
After taking x-rays he said he was puzzled because he could not see any signs of anything unusual. He gave me Cosequin powder for cats which I have not tried yet. This is all driving me crazy because her limp is getting worse although she does not appear to be in any pain. Where do I go from here?
   
What exactly is Cosequin? Is it just a supplement? Any side-effects? Could the limp be a result of the declaw three years ago? An underlying disease? Help!

Declawing doesn't usually cause a side-effect 3 years later.
   
The cat may have early arthritis or other joint problems; it's not uncommon. The steroids made her feel better because steroids improve the muscles & joints as long as they last, but you can't use steroids long-term.
   
Cosequin is Glucosamine & Chondroitin for pets, the same thing humans take for joint support & aches, & arthritis. Follow this link: http://www.entirelypets.com/cosregstren1.html. This is the bottle to buy; online, it's cheaper. This size dose is perfect for cats: one capsule opened up & worked into the cat's food per day is the right dose. I used it for my old cat with arthritis.
   
There are no side effects that could hurt your cat.
   
Cosequin takes a couple of weeks to have a full effect, so don't worry if it doesn't improve her quickly. If it works, then just keep her on it for the rest of her life.
   

Thank you! I started the cosequin this week - hopefully I will see some improvement. Would these joint/arthritis issues have shown up on the x-rays my vet took? He said everything looked normal which is why I was so concerned.