Wow...So a little over than a year later and Buddy now has the same problem. This time I saw how it happened.
Yesterday during the fireworks I decided it would be a good idea to climb on the roof and get a better view of aerials throughout the island (Oahu, Hawaii). Well, being that he is a Boston Terrier Buddy decided to follow. I climbed on my daughter's swing set (Plastic type with stairs and slide) and hopped on the roof.
Buddy had the same idea, climbed up the steps and tried to follow but ended up not jumping high enough and fell about 4 ft.

He kept on trying until I told him to sit. He didn't go lame until this evening after we got back from watching Marley & Me of all movies.
He's chilling right now on the couch, the vets on post were closed. I have their private number but that's just in case one of my patrol dogs go down. Hopefully, all goes well tomorrow and he'll be back to normal.