Type B1 fractures are simple fractures of the base of the femoral neck.
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 this type of fractures challenging.
31-B fractures are simple fractures of the femoral neck. These fractures may or may not be displaced. Fixation should be performed as soon as possible to avoid abrasion damage and resorption of the femoral neck, making reduction difficult.
Cervical fractures can be intracapsular or extracapsular.
In very young animals, fractures of the greater trochanter may occur concurrently to a capital physeal fractures.
31-B fractures occur secondary to trauma and are commonly seen in young patients.
Growth plate fractures are typically Salter-Harris type I. Fractures of the trochanteric physis coexist in 11-15% of the cases. In young adult dogs and cats the physis may separate without trauma, affecting one or both capital physes in a disease called capital physeal dysplasia.
Normally the joint capsule remains intact and in some cases the minimal displacement of the fragments makes diagnosis difficult, particularly on the extended, ventro-dorsal radiographs. An abducted ventro-dorsal (frog leg) view of the hip joint often displaces the femoral neck, making the fracture more detectable.
Clinical signs observed in 31-B 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. The minimal displacement of the fragments may make the diagnosis difficult. An abducted ventro-dorsal (frog leg) view of the hip joint often further displaces the femoral neck, making the fracture more detectable.
Radiographs of the contralateral femoral head might be needed for comparison purposes.