I would get a second opinion from an orthopedic vet. If he also recommends surgery you should go ahead and do it as the best window of time for healing is soon after the leg is broken.
We've had cases here on YT where the owners didn't opt for surgery for a broken leg and the leg had to be amputated because it didn't heal.
http://www.yorkietalk.com/forums/sic...oken-legs.html http://www.yorkietalk.com/forums/sic...roken-leg.html http://www.yorkietalk.com/forums/sic...roken-leg.html