These are split fractures of the femoral head that involve the articular surface. They disturb both the blood supply and the congruity of the articular surface. They are very often associated with a hip joint dislocation. The combination with an acetabular (posterior wall) fracture is also frequently seen.
In general, fractures of the femoral head are associated with dislocation of the hip. In 90% of cases, the dislocations are posterior and in 10% anterior.
An unreduced dislocation is an emergency because it threatens the blood supply to the femoral head. It may also be accompanied by pressure on a major nerve. Therefore, emergency reduction must be performed. If closed reduction succeeds, one has the luxury of time to investigate the patient further with a CT and then evolve an appropriate treatment rationale. If closed reduction fails, emergency open reduction must be undertaken.
Small fragments, which do not involve the weight-bearing portion of the femoral head, may be considered for primary resection, particularly if they block an anatomical reduction of the hip.
For an accurate diagnosis one needs AP and lateral views of the hip, and Judet views of the pelvis. The most accurate information comes from a CT. The diagnosis is often missed in case of small fractures, but even larger fractures are not always apparent on a standard pelvic x-ray.