Hypothesis 1 Ð Bone Fracture

The dog was hit by a car three days ago, and now has a Grade IV bilateral non-weight 
bearing lameness in the hind limbs. Possible causes of the right hind limb lameness include 
a mid-shaft fracture of the tibia. This would be supported by the incontinuity in the tibia 
found during the orthopedic exam. Radiographic signs might include fracture lines and 
fissures, localized soft tissue swelling, bone fragments, and alterations in bone shape, 
length, and rotational direction. 

The left hind limb is also non-weight bearing, and possible etilogies include coxofemoral 
joint damage, proximal femoral fracture, and / or damage to the acetabulum. There is also 
diffuse swelling of the left hind limb, due to venous outflow obstruction in the proximal 
limb, inhibiting lymphatic and vascular drainage and causing congestion / edema. 
Crepitation was noted during the orthopedic exam, and crepitation is usually noted from 
abrasion of fractured bones surfaces, from joint effusion, or from emphysematous tissue.
This crepitation is likely due to fractured femur or coxofemoral joint damage. Diffuse 
swelling prevented exact localization of the injury. Abnormal limb movement further 
supports fracture or luxation of the limb.
Possible radiographic signs include soft tissue swelling, bone discontinuity, cortical bone 
destruction, bone fragments, and abnomalities in bone shape, length, and rotational 
direction.