Type A3 fractures are multifragmentary fractures of the trochanteric region.
A3 fracture in a domestic shorthair cat, combined with an acetabular fracture.
High-velocity injuries of the proximal femur generally result in intertrochanteric or subtrochanteric comminuted fractures. Low-velocity injuries result in lower energy fractures and often result in two-piece fractures such as capital physeal fractures, femoral neck fractures or transverse fractures of the subtrochanteric region.
The small bone stock available for fixation in the proximal femoral fractures makes treatment of these types of fractures challenging.
31-A1 and A2 type fractures generally result from low energy trauma, whereas A3 fractures are caused by high energy trauma.
Fractures of the greater trochanter occur in young animals, often associated to capital physeal fractures.
Clinical signs observed in 31-A fractures are:
Crepitus during manipulation of the hip joint
Non weight bearing of the affected limb
Good quality mediolateral and craniocaudal radiographs are essential for fracture evaluation.
In A1 fractures the avulsed fragment may be overlapped by the femur, making diagnosis challenging. In some fractures, the abducted ventro-dorsal view (frog leg) may provide useful additional information.
For complex fractures, computed tomography should be considered.