In extracapsular fractures there is minimal risk of osteonecrosis of the femoral head.
In multifragmentary pertrochanteric fractures the fracture line can start laterally anywhere on the greater trochanter and runs towards the medial cortex which is broken in two places. This results in the detachment of a third fragment which includes the lesser trochanter.
These fractures cause significant shortening and tend to be unstable after reduction and fixation, because the medial buttress is compromised.
These fractures may be treated with a sliding hip screw and plate, or a cephalomedullary nail. The sliding hip screw is designed to allow controlled collapse. The collapse is limited as the base of the neck comes to rest on the greater trochanter. If the greater trochanter is very comminuted control of the collapse is lost. A trochanteric supporting plate (TSP) may be used to restore the supporting effect of the greater trochanter.
In case of a simple pertrochanteric fracture with a lesser trochanter fragment, a 4-hole DHS plate without TSP might be sufficient. For fractures with an incompetent lateral wall, extramedullary devices are only second choice, as they lack necessary stability.
Note: Because healing of these fractures may take 12 or more weeks, if contraindications can be corrected soon enough, operative treatment of the fracture may be beneficial even if delayed.
If definitive treatment will be delayed for more than 2 or 3 weeks, temporary skeletal traction might be considered to help maintain alignment.