saving time quoting from "sore front leg" thread "google PANOSTEITIS - aka pano aka long bone disease
self limiting - will go away all on its own
vet should have considered this , MALE, age , breed
in future it may shift to another limb , hind or fore , may disappear for a period , then come back , could last till the dog is 2 years. May disappear for long period , months, and then some trauma , over exertion, bump , will bring back inflammation."