To update, icedcoffees was correct - my pup was diagnosed with elbow dysplasia.
The orthopedic vet was just more skilled in reading the x-ray.
Fast forward a month and pup is now on crate rest, after having BOTH elbows CT scanned and arthroscopically treated by that orthopedic vet.
A little fragment of the coronoid process on the right elbow (about the size of a lentil) had come away and needed to be removed, and there was a little hairline fissure in the coronoid process of the left elbow.
The vet said that now the fragment is removed, the right elbow should be much better, and with the crate rest, the fissure in the left should also just heal. He said there was little to no damage of the cartilage, thank goodness and that (other than the above,) 'the elbows looked very clean.'
I felt really positive when my boy returned home that all would be well and as the vet said, 'It's about the best prognosis for this condition', but as the days go on, I'm in despair - my pup (understandably I suppose at 8 months) just will not 'rest'!
Ie if I don't give him toys actually in his crate like nylabones, frozen kongs, little puzzle toys etc (which he holds and moves around with his feet) he will paw at the bars or dig at his bedding - so essentially, either way... I can't keep his paws/legs still! Also, because he has so much pent up energy, when he CAN go on the lead to the toilet, he is like a pup possessed and I am having to hold on so tight and close to his collar, so that I can stop him zooming/jumping.
I think today I'm looking for reassurance that compared to puppies' normal daily activity levels (off lead walks, zooms in the garden etc,) my pups idea of crate rest is still rest and he will still heal, specifically that fissure?
Anyone any similar experiences?