Just seen your post, We have a Guy that races at OVKA that owns Full Throttle Karting in Cincinnati, Ohio Aaron Banfield . He has set up a rental kart with hand controls for those with physical limitations . Feel free to give them a call, They have done the homework on providing a kart that is safe, maybe your local track will be interested in setting one up for your kids and others , Here is a quote from their web page https://www.gofullthrottle.com/go-racing/karts/
Hand Control Kart
Our latest addition to the fleet of go-karts is far and away the coolest one we’ve delivered yet. Introducing the #99 hand control kart! Developed hand-in-hand with help from the Racing 4 Vets program and Mobility Works, we’re proud to offer a karting opportunity to people with disabilities. And yes, this kart is every bit as fast as our standard adult karts, tearing through corners at speeds up to 40mph! Looking for more information? Give us a call at 513-34-5278!