Background: Vascular injury after femoral neck fracture can determine its prognosis. This study aimed to determine methods of evaluating femoral neck fracture and accurately predicting the prognosis.
Methods: Forty-five patients with a single femoral neck fracture all underwent digital subtraction angiography (DSA) and were divided into three types by DSA. DSA showing three to six supporting band vascular images crossing the fracture line was classified as type I. DSA showing one to two supporting band vascular images crossing the fracture line was classified as type II. When DSA did not show vascular images crossing the fracture line, it was classified as type III. The 45 patients were divided according to age into elderly, middle-aged and youth groups. All cases were given internal fixation operations by a hollow screw under a C-brachial machine. After a follow-up of 6-60 months, avascular necrosis of the femoral head (ANFH) and fracture healing of different type and different ages of patients were evaluated according to symptoms and imaging examinations.
Results: (1) For DSA types I, II and III, the rates of ANFH were 0, 7.14 and 100 %, respectively, and the rates of fracture disunion were 13.3, 7.15 and 0 %, respectively. Therefore, the rate of ANFH is negatively related to the visible supporting band vascular amount on DSA. (2) In the young group, the proportions of types I, II and III were 6.7, 26.67 and 66.7 %, respectively, 18.18, 36.36 and 45.45 % in the middle-aged group and 63.16, 31.58 and 5.27 % in the elderly group. The rates of necrosis for elderly, middle-aged and youth were 10.53, 45.45 and 66.67 %, respectively, and the rates of fracture disunion were 0, 0 and 6.67 %, respectively. So we can draw the conclusion that the amount of supporting band vascular images is inversely proportional to age and the union is directly related to age, but independent of the supporting band vascular amount of DSA showing.
Conclusion: The new classification after superselective angiography is valuable for predicting the prognosis of femoral neck fractures.