Chihuahuas

I just found out my 6 years old chihuahua, Duke, has a luxating patella. My son was carrying him down the stairs and at the bottom my dog got overly excited and started flipping around and my son accidentally dropped him. We took him to the vet immediately where he was diagnosed with a level 4 luxation. Duke favors that leg, ie. will not run on it, but he will stand on it, and occasionally use it when he is walking. He doesn't yelp or seem to be in any pain, but my vet recommends surgery to repair it. She said they would increase the grove and pin it. The surgery will be about $1,400.00. They didn't do an xray and said it was better to do them a day or two prior to the surgery. His diagnosis cost $61.00. I asked my holistic pet specialist who said I should start him o glucosamine and aspirin therapy for about 5 days and see if he shows more stability. Because it was caused by trauma and the tendon is still relatively tight it could be inflammation preventing the patella from staying in place.I can pop it back in place, but it pops back out shortly after. I am trying the aspirin therapy and will start the glucosamine as soon as it comes in. I am afraid that waiting a week or two could cause more damage, but I am terrified of putting him through an unnecessary surgery if at all possible. He weighs 5.9 pounds, and anesthesia is a big concern because he will be under for about and hour and a half. I am getting a second opinion just to make sure, but it is an obvious diagnosis because as an amateur, even I can feel it and manipulate it. Am I on the right track? Will the surgery help? How can it be a level 4 already when he doesn't even so much as whimper? Any insight or suggestions would be appreciated. Duke is one of four dogs that I own, and I want to make sure that his quality of life is good and that he will be able to continue playing and interacting with his "family". I own two other chihuahuas, and a pit bull, so the activity level in my house is always random.