Vet Tech is a very physical job. There is a lot of standing, walking, stooping, squatting, reaching, lifting, pushing, pulling, holding, and more--not much sitting. Cleaning is a great part of a VT's day-to-day work, plus handling chemicals, vapors and radiation exposure, and the risk of being bitten, scratched, kicked, etc.
I'm sure you would invest in the appropriate footware and wear ankle supports. However, using a cane might prove a bit difficult and awkward for the physical demands on a Vet Tech.
Reception or practice management are less physically demanding. Just my two cents. Good luck whichever direction you choose!