Three days later Scotty was again seen for pain, and his owners said that the day before he had been scared by a dog outside and had perhaps moved too quickly. After a physical exam, while holding Scotty gently on the exam table in a minimal restraint position for blood collection, we heard a loud snap/crack sound and he screamed. Scotty had a dramatic spontaneous fracture of the right femur!!!
After anesthesia and radiographs a right femoral mid-shaft oblique closed fracture was diagnosed.
The orthopedic surgeon that had fixed Scotty's fracture was called in and he operated again. This time he noted that each time he applied a bone clamp, the bone fragments broke. The surgeon was forced to plate and pin the fracture, with bones breaking as he worked.
Blood work for blood calcium and phosporus levels all came back normal, as did a routine blood panel. This was not hyperparathyoidism or faulty Vitamin D metabolism. This was not rickets either since Scotty had been eating a premium brand puppy food for large breed dogs.
The owner checked on littermates; as of April one female had subluxated her shoulder, one male had also fractured his femur.
Bone fragments were sent to the lab for histopathology. The pathologist made a diagnosis of osteogenesis imperfecta.
Later on, blood was sent to a lab in Germany for genetic testing of osteogenesis imperfecta, but came back as inconclusive, as they only confirm their results in Daschunds, not in this mixed breed dogs. That was frustrating…
We are assuming that Scotty and his littermates do indeed have osteogenesis imperfecta. Osteogenesis imperfecta is a genetic disease in people and in dogs. Given that multiple mutations can cause osteogenesis imperfecta in people, the fact that Scotty does not have a specific mutation and tested negative or inconclusive on the German genetic osteogenesis imperfecta test does not mean much. The German lab even said that “there is a possibility that other mutations may have caused the disease/phenotype”. Had we gotten a positive result it would have been a lucky finding that Scotty carried this specific mutation. The disease therefore has variability in its severity and expression. Scotty does not have the full blown osteogenesis imperfecta seen in some Daschunds, for example.
Further history from litter mates revealed that by July, several of them had each fractured their femurs…. Twice!
Scotty was neutered in July in order to prevent this sad story from perpetuating through another generation.
Scotty has now grown into a young adult he uses his left hind leg as a ‘cane’ while walking, and has valgus deformation. In January 2013 Scotty had a corrective orthopedic surgery at the Veterinary Teaching Hospital in Bet Dagan where his left femur was refractured and repositioned in a correct anatomical position.
