42-A2 are simple oblique fractures of the tibial diaphysis.
Spiral fractures are not explicitly included in this classification. However, as their treatment is often similar they will be included for this reference under A2 type fractures.
Spiral and long oblique fractures are usually caused by torsional forces. They typically occur after a sudden turn during running, while playing.
Oblique fractures can be subcategorized as “short oblique” (fracture line is between 30° and 60° relative to the long axis of the bone) and “long oblique” fractures (<30° relative to the long axis of the bone).
42-A2 type fractures have a fractured fibula.
The tibia has an S-shape in the frontal plane. This characteristic can be more pronounced in chondrodystrophic dogs. Even though this will not influence the fracture fixation method, it is important to bear it in mind when reconstructing the fracture and restoring the normal anatomy.
The fibula at the level of the tibia midshaft is very thin. For this reason, fractures of the fibula are generally not addressed.
42-A type fractures generally result from low energy trauma.
Clinical signs observed in 42-A fractures are:
Edema of the region
Abnormal movement in the tibia shaft
Dogs with A1 type fractures may present with mild to severe non-weight bearing lameness. Dogs with incomplete fractures may still be able to use the limb.
Craniocaudal and lateral radiographic views are needed.