This study included 309 patients, over the age of 60 (44 men, 256 women, mean age 85.6 years) who underwent osteosynthesis using a short femoral nail(Gamma)for femoral intertrochanteric fractures. The new reduction classification was defined, in AP view by the degree of contact between the medial cortex of the proximal fragment and that of the medial cortex of the distal fragment. The classification in AP view is divided into three Types: Anatomical Type, Medial Type, and Lateral Type. As for the ML view was defined based on the degree of anterior cortex contact between proximal and distal fragment, was divided also into Anatomical Type, Intramedullary Type, and Extramedullary Type. We assessed lag screw sliding amount at 2 weeks period after surgery as the post-operative displacement. The sliding at 2 weeks was in AP Anatomical Type 3.7mm, in Medial Type 3.2mm and in Lateral Type 9.4mm. The sliding in the Lateral Type was much greater than those of Anatomical Type and Medial Type (Significant p-value, p=0.01, 0.01). Likewise, in the ML view, Anatomical Type 3.0mm, Intramedullary Type 6.2mm and Extramedullary Type 4.7mm respectively. There was a significant difference between ML Anatomical Type and Intramedullary Type(p=0.01).Materials and method
Results
Fracture classification of femoral trochanteric fracture is usually based on plain X-ray. However, complications such as delayed union, non-union, and cut out are seen in stable fracture on X-ray. In this study, fracture was classified by 3D-CT and relationship to X-ray classification was investigated. 48 femoral trochanteric fractures (15 males, 33 female, average age: 82.6) treated with PFNA-II were investigated. Fracture was classified to 2part, 3part(5 subgroups), and 4part with combination of 4 fragments in CT; Head (H), Greater trochanter (G), Lesser trochanter (L), and Shaft (S). 5 subgroups of 3 part fracture were (1) H+G (S: small fragment) + L-S, (2) H + G (B:big fragment) + L-S, (3) H + G-L + S, (4) H + G (W:whole) + S, and (5) H + L + G-S. Numbers of each group were as follows; 2 part: 11, 3 part (1) : 7, 3 part (2) : 12, 3 part (3) : 10, 3 part (4) : 2, 3 part (5) : 3, 4 part : 3. 3 part (3), (4), (5) and 4 part are considered as unstable, however, 6 cases in these groups were classified in A1–1 or A1–2 stable fracture in AO classification. 10 fractures in Evans and 5 fractures in Jensen classification classified as stable were unstable in CT evaluation. It is sometimes very difficult to classify the femoral trochanteric fracture by plain X-ray. Classification with 3D-CT is very useful to distinguish which fracture is stable or unstable.
