Knee rover brand is what a lot of medical places like to recommend. I’m not sure which one and I have never had to use one. This is from working in medical and over hearing things in the past.
I've broken my foot a couple times and have had foot surgery a couple more times. Usually, knee scooters are prescribed by the doctor and now use this OasisSpace All Terrain scooter. I think you might ask him for a prescription covered by insurance.