Does Anyone Know How Much Glucosamine/chondroitin I Should Give My Dog To Help Heal A Torn Ligament?

My terrier (18lbs) has torn her acl ligament. I’ve found on the web that glucosamine/chondroitin helps to heal this problem, but I can’t find any information about how much to give her. My vet doesn’t know (I’m from a small town and the local vet tends to prescribe pain medicine rather than vitamins). Does anyone know where I can find this out?