1. Image of The Day 4 : Left Anterior Hip Dislocation
Muhamad Na’im B. Ab Razak (MD USM)
This Pelvis X Ray shows a very typical feature of anterior left hip dislocation. The features
are as follow 1) Prominent lesser trochanter, 2) Hip is in abducted position, 3) Femur head is
inferior to acetabulum and 4) Disrupted shenton line.
Anterior hip dislocation rarely occur and constitutes about 5-10 % of all hip dislocation. In
contrast to posterior hip dislocation that associates with fracture, anterior hip dislocation
usually occur in isolation. If to be associated with fracture, the percentage is very low and
may involve impaction fracture of femoral head and acetabulum fracture.
Anterior hip dislocation could further be classified into two main type which are superior and
inferior. In superior dislocation, the femoral head is displaced into the iliac or pubic region.
Meanwhile, in inferior anterior hip dislocation, the femoral head lies in the obturator region.
Mechanism of injury usually involves hyperextension of the abducted leg that will levers the
femoral head out of acetabulum.
Often, this mode of injury will require open reduction and stabilization of the dislocted
femoral head. Leave untreated, it may lead to neglected dislocation causing early
osteoarthritis and requiring total hip replacement surgery.