Abstract
The purpose of this study was to investigate the sinking distance of the intramedullary nail in case of femoral trochanteric fracture. Since January 2009, intramedullary nails have been used to treat femoral trochanteric fracture in 38 patients. There were 34 females and 4 males with a mean age of 83 years at surgery. Gamma 3 systems (Stryker) with a U-lag screw implant were employed in all cases. Fracture stability was assessed in terms of medial bone contact evident on 3D-CT, and the reduction was assessed by radiographic evaluation in lateral view (Ikuta's classification). Patients were classified into four groups according to whether or not medial bone contact was evident in the lateral view classification. The nail sinking distance and the filling ratio of the stem in the femoral canal were examined at four weeks after the operation, and statistical analysis of inter-group differences was conducted. The mean nail sinking distance was significantly shortest in the group with medial bone contact and the A+N subtype. There were no significant differences among the four groups in the stem filling ratio. The group without medial bone contact and the subtype P group were each classified into two groups on the basis of the stem filling ratio (80%). The filling ratio was related to the sinking distance in these two groups. The present findings suggest that the stem filling ratio plays an important role in nail sinking, specifically in patients without medial bone contact and the subtype P group.
