In these fractures, the fracture line can start laterally anywhere on the greater trochanter and runs towards the medial cortex which is broken in two different places. This results in the detachment of a third fragment which includes the lesser trochanter.
Fractures with an intact lateral wall (>20.5 mm) and a small lesser trochanteric fragment may be considered stable after anatomical reduction.
Fractures with an incompetent lateral wall (≤20.5 mm) are unstable after reduction. The greater trochanter is involved and fractured and often displaced. The exact fracture pattern is often difficult to determine on emergency x-rays.
The posteromedial loss of bone combined with certain fracture patterns makes these fractures unstable and difficult to treat. There is an ongoing discussion as to which is the best implant for their fixation. Generally, the less stable the fracture, the greater the indication for intramedullary fixation.
X-rays taken from Orozco R et al, (1998) Atlas of Internal Fixation. Used with kind permission.