Introduction: The use of intramedullary nailing (IMHS) has increased at the expense of the dynamic hip screw (DHS), although the outcome is not different in the studies of pertrochanteric fractures (PTF), known as AO/OTA type 31A1-2 fractures with a preoperative intact lateral femoral wall. We therefore investigated the two implants in the subgroup of PTF with a fractured greater trochanter.

Materials and Methods: Six hundred thirty-five consecutive patients with PTF fixated by a short IMHS or by a DHS mounted on a four hole lateral plate were prospectively included between 2002 and 2008. The fractures were preoperatively classified according to AO/OTA classification system, including status of the greater and lesser trochanter. The integrity of the lateral femoral wall, fracture reduction and implant positioning were assessed postoperatively. Reoperations due to technical failures were recorded for one year.

Results: Among the 311 patients sustaining a PTF with a fractured greater trochanter, 4% (6/158) operated with an IMHS were reoperated compared to 14% (22/153) with a DHS (p=0.001). Multivariate logistic regression analysis combining demographic and biomechanical parameters showed the IMHS to have a lower rate of reoperation (p=0.002).

During the operative procedure, the lateral femoral wall was fractured in 6% (9/158) of patients, in which an IMHS was performed versus 28% (42/153) operated with a DHS (p< 0.001). Among the DHS, a fractured lateral femoral wall was confirmed to be a predictor of a reoperation (31% (13/42) of patients with a fractured lateral femoral wall versus 8% (9/111) with an intact lateral femoral wall, p< 0.001).

As in other studies, the different reoperation rate would have been overseen in the main group of AO/ OTA type 31A1-2 PTF fractures (4% (6/164) IMHS versus 6% (30/471) DHS, p=0.196).

Conclusion: The IMHS seems to have a lower reoperation rate than the DHS in the subgroup of PTF with a fractured greater trochanter. In contrast to the DHS, the IMHS presumably keeps the integrity of the lateral femoral wall. In future studies, PTF should be divided into subgroups.