Subtrochanteric fractures are fractures of the hip below the greater and lesser trochanters. They are essentially fractures of the shaft of the femur up to 5 centimeters or less below the lesser trochanter. They account for up to 30 percent of fractures of the hip and can occur at many different age levels. This injury is already subjected to high forces from standing or walking on the leg.
The bone is highly compressed already, especially in the medial and posterior-medial parts of the femur. The bone has few blood vessels in this area so it tends to heal more slowly with a higher risk of nonunion than with other parts of the femur. There are several muscles which attach to this area that cause the fracture to deform when broken. This includes the gluteus muscle, the short rotator muscles and the psoas muscle.
The mechanisms of injury include low energy injuries in which the elderly person sustains a minor fall and breaks a weakened bone. High energy impacts can cause fractures in young people. This includes motor vehicle accidents, gunshot wounds, and falls from a great height. Pathological fractures from metastatic cancer or Paget’s disease cause up to 35 percent of all subtrochanteric fractures.