[Case-control study on double screws system and compressed three canulated screws in treating femoral neck fractures]

To compare the clinical effects of double screws system and compressed three canulated screws in treating femoral neck fractures.

From January 2007 to June 2009, the clinical data of 67 patients with femoral neck fractures underwent operation were retrospectively analyzed. There were 38 males and 29 females,aged from 31 to 71 years with an average of 50.6 years, left was in 41 cases and right was in 26 cases. The patients were divided into two groups (group A and B) based on the different fixation method. Of them, 30 cases (group A,19 males and 11 females) were treated with double screws system and 37 cases (group B, 19 males and 18 females) with compressed three canulated screws. In group A, Pauwells angle was more than or equal 50 degrees in 16 cases and Pauwells angle less 50 degrees in 14 cases; in group B, Pauwells angle was more than or equal 50 degrees in 22 cases and Pauwells angle less 50 degrees in 15 cases. Duration of hospitalization, operative time, intraoperative blood loss, postoperative time in bed, infection of incision, postoperative complication, quality of fracture reduction, position of internal fixation, incidence of non-union and femoral head necrosis, incidence of failure fixation, joint function (Harris score) were compared between two groups.

All patients were followed up from 30 to 59 months with an average of 42 months. There was no significant differences in aspect of duration of hospitalization, infection of incision, intraoperative blood loss, walking time, postoperative complications between two groups(P>0.05). Operative time of group A [(31.1 +/- 9.7) min]was less than that of group B [(40.4 +/- 12.7) min] (P<0.05). There was no significant differences in quality of fracture reduction, position of internal fixation, incidence of non-union and femoral head necrosis between two groups (P>0.05). In the patients with Pauwells angle more than or equal 50 degrees in group A, there was no retreated screws, broken screws, screw cut-off from the femoral head;a head;and in group B, retreated screws occurred in 2 cases, screw cut-off from the femoral head occurred in 2 cases, screws not completely getting in femoral head occurred in 2 cases; there was significant differences between two groups (P<0.05). The patients with Pauwells angle less 50 degrees in group A, screw loosening occurred in one case; and in group B, screw retreating occurred in one cases; there was no significant differences between two groups (P>0.05). All patients who suffered from screw loosening, retreating or cut-off from the femoral head were more than 65 years old. There was no significant differences in the joint function between two groups at 6 and 30 months after operations (P>0.05).

Double screws system has advantages of minimal invasion, easy operation, reliable fixation in treatment of femoral neck fractures. Compared with the traditional compressed three canulated screws,double screws system has less fixation failure rate and higher hip function scoring. It has a good clinical effect especially for the patients with Pauwells angle more than or equal 50 degrees.