Background: Surgery for intertrochanteric fractures using intramedullary hip nails (IHNs) is one of the most common surgeries in the orthopedic field. Although IHNs provide a good overall outcome, they sometimes cause complications (e.g. a loss of reduction and cut-out). We compared the usefulness of IHNs with an anterior offset (Best Fit Nail® [BFN]) in maintaining the reduction of fragments and ensuring proper lag screw positioning to that with conventional non-offset nails, using postoperative computed tomography (CT).
Methods: Fifty consecutive patients with intertrochanteric fractures who underwent surgery with BFNs (BFN group) and 50 patients who underwent surgery with conventional non-offset nails (control group) were retrospectively analyzed. Indices evaluated by postoperative CT comprised the displacement distance of proximal fragments relative to distal fragments, reduction status (intramedullary, anatomical, and extramedullary types), screw direction, and the angle between the screw and the femoral neck axis (deviation angle).
Results: The median displacement distance [interquartile range] was significantly smaller in the BFN group (0 [0, 0] mm) and in the control group (4.4 [3.1, 6.3] mm) (p<0.0001). Additionally, the reduction status was significantly better in the BFN group (anatomical type in 40 cases, intramedullary type in 9 cases, and extramedullary type in 1 case) than in the control group (anatomical type in 6 cases, intramedullary type in 40 cases, and extramedullary type in 4 cases) (p<0.0001). Deviation of the lag screw direction was observed in significantly fewer cases in the BFN group (20 cases; 40%) than in the control group (35 cases; 70%). The deviation angle of the lag screw was significantly smaller in the BFN group (-0.71°±4.0°) than in the control group (5.7°±5.3°). No adverse events related to surgery were observed in either group.
Conclusions: Intertrochanteric fracture surgeries using BFNs exhibited significantly smaller displacement distance, better reduction status, and higher frequency of no deviation, with central lag screw positioning, compared to those using conventional non-offset nails.