Subtrochanteric or Reverse Obliquity Fractures
Strong evidence supports using a cephalomedullary device for the treatment of patients with subtrochanteric or reverse obliquity fractures.

There were 3 high (Sadowski et al 97, Zhang et al 98, Schipper et al 99), and 2 moderate strength (Miedel et al 100, Hardy et al 101) studies evaluating the use of cephalomedullary devices in the treatment of unstable intertrochanteric and subtrochanteric fractures. Although many comparative studies have been done, the variability of fracture classification systems and implants used makes interpretation of the literature challenging.  Evaluation of these studies shows an apparent treatment benefit with cephalomedullary devices for unstable peritrochanteric fractures.
One high strength study (Sadowski et al 97) that  specifically evaluated reverse oblique and transverse intertrochanteric fractures (OTA 31.A3) found lower failure rates, blood loss, and operating room time in the cephalomedullary nail cohort versus a 95º fixed-angle device with no difference in functional results.  Two high strength comparative studies showed similar results and outcomes between different cephalomedullary devices in unstable fractures (Zhang et al 98, Schipper et al 99).
A moderate strength study (Miedel et al 100) demonstrated a lower complication rate with use of a cephalomedullary versus an extramedullary device in treatment of unstable intertrochanteric and subtrochanteric fractures.  Another moderate strength study (Hardy et al 101) showed improved mobility and decreased limb shortening in unstable intertrochanteric fractures treated with a cephalomedullary device versus a sliding hip screw.
Risk and Harms of Implementing this Recommendation
There are no known harms associated with implementing this recommendation
Future Research
Continued comparative studies between modern cephalomedullary and extramedullary devices in unstable subtrochanteric and reverse obliquity fractures (OTA 31.A3) which control for fracture reduction and implant position (specifically tip-to-apex distance) may further clarify the utility of cephalomedullary devices for this fracture cohort.