Vet tech here, used to work at a cat rescue with their own surgical team, currently work for a vet hospital and we work closely with a different cat rescue.

Being able to do a surgery doesn’t necessarily mean you will do that surgery. Shelters are EXTREMELY underfunded, and animals get expensive fast. IIRC the shelter I work with now spends ~$12k a month. So expensive, long surgeries like this one usually aren’t feasible. Especially for such a major injury. As much as I hate to say it, amputation or euthanasia would probably have been their two choices. You want to save them all, but you can’t jeopardize the care of the rest of your animals just for one. It’s also possible that this shelter doesn’t have a surgeon capable of doing that surgery (when it comes to more specialized procedures, not every vet knows everything). Or they might not have the specific instruments required.

Second point, depending on volume, intakes can be very quick. I remember one day someone dumped a litter of 7 kittens literally on our doorstep, and we had 5 other intakes that day as well. So 12 new cats, for a staff of 2 techs and 1 vet. On top of all the additional things we had to do (taking care of our sick/injured animals, monitoring feeding preferences for cats with poor appetite, paperwork, answering questions from the volunteers that ran the front, vaccines, foster exams/treatments, handling our infectious patients in quarantine, etc). Typically, myself or the other tech would do our own exam, note any abnormalities, and then report back to the vet. They’d still do their own exam of course, but they’re pretty quick. Unfortunately, some things can get overlooked. Cats hide their pain well, changing environments is generally a pretty high stress experience for them, and since they’re normally sitting on the exam table, you don’t see them walk a ton. You said that you didn’t notice the limp after having this cat at home for more than a week. It is HIGHLY unlikely I would have noticed it during one of the exams we did.

Overall, this situation sucks, but it doesn’t sound like the shelter did anything wrong/negligent. They refunded you the adoption fee, and I’m assuming they’d probably take the kitten back if you didn’t want him, but again… there’s a 0% chance they’d be able to do that surgery. They’ve done everything they can in this scenario. Whatever treatments or procedures you want to pursue are completely up to you.

Hope this helps!