Weakness in back leg

[MrsElm]

I'm looking for advice about our 7 yr old tabby. Over the last few months we have noticed that she seems to have a weakness in one of her back legs. She has a bit of a wobble or wiggle when she runs, and sometimes the leg slides out from under her.
The vet examined her and could find no reason for this, and prescribed anti inflammatory medication, however this has not really helped.
She doesn't seem too distressed, is still going out and eating. She is miaowing more, but isn't crying out in pain when she walks or lands on her back legs.
Has anyone experienced anything similar or knows what might be causing this? The vet mentioned having her back in for an X-ray, but she is so distressed by trips to the vet! So I would only want to put her through that if it is really necessary and would improve her condition.

Would appreciate thoughts and advice.

Her name is Topsy, and here she is enjoying the sunshine!

That's a strange one. I think the only way to know what's going on is to get an x-ray. Not what you want to do, I know. My cats have had limps from time to time, which have worried me. But they've gone within a couple of days and I've put it down to scrapping with other cats. Has she had painkillers? I'm not sure how effective anti inflammatories are for that?

@Want2beme thank you for replying. The vet said that the meds were good for pain relief also.

I think I will call them tomorrow to discuss.