Comparison between AO/OTA Type 31-A2 femoral pertrochanteric fracture fixed with dynamic hip screw with two and four side screws

Background: Treating AO/OTA Type 31-A2 femoral pertrochanteric fracture with closed reduction and internal fixation utilizing a dynamic hip screw (DHS) with 4 side screws has been undoubtedly the most common surgical method. Purpose: The aim of this study was to explore whether a DHS with 4 side screws can be substituted by a DHS with 2 side screws when treating this type of injury. Methods: In total, 259 patients with AO/OTA type 31-A2 pertrochanteric femoral fracture fixed using a DHS with 4 side screws or 2 side screws were retrieved retrospectively for dates from December 2004 to December 2007. In this study, the 128 fractures fixed with DHS with 2 side screws were classified into group A, while the 131 fractures fixed with DHS with 4 side screws were classified into group B. Demographic and clinical parameters, such as age, gender, injury site, surgical time, amount of blood transfusion, and whether major implant related complication developed, were compared between the two groups. Results: No significant differences between the two groups for demographic parameters such as sex, age, and injury site were found. The surgical time of group A (87.6 ± 28.3, range: 35- 175 minutes) was significantly shorter than the surgical time of group B (109.8 ± 34.1, range: 40-210 minutes) (p ＜ 0.001). Moreover, the amount of blood transfusion for group A (2.16 ± 2.16, range: 0- 10 units) was significantly less than the amount of blood transfusion for group B (2.98 ± 2.37, range: 0-8 units) (p = 0.004). The development of major implant related complications among patients in group A was statistically equivalent to group B. Conclusion: Treatment of AO/OTA type 31-A2 femoral pertrochanteric fracture by DHS with 2 side screws gave a comparable outcome with respect to the development of major implant related complications and was superior in terms of surgical time and amount of blood transfusion compared with a DHS with 4 side screws. The use of a DHS with 2 side screws can therefore be regarded as an alternative implant to a DHS with 4 side screws when treating AO/OTA type 31-A2 femoral pertrochanteric fracture.