Distances between popliteal vessels to the femur and anthropometric impacts on distal femoral fracture surgery outcome: a retrospective study

Background:The proximity of the popliteal vessels in the distal femur may increase the risk of iatrogenic vascular injury during cerclage wiring. In this study, the closest location and distance of the popliteal vessels to the femur was examined using magnetic resonance imaging (MRI). The associations between anthropometric factors and the distance that would guide the placement of wires safely during surgery were also identified.Methods:We reviewed knee MRIs of 206 adults and recorded 1) the relation as well as the shortest horizontal distance (d-H) from the femoral cortex to the popliteal vessels in axial images and 2) the vertical distance (d-V) from the adductor tubercle to the axial level of d-H in coronal images. The effects of anthropometric factors (i.e., gender, age, body height, body weight, body mass index, thigh circumference, femoral length, and femoral width) on these distances were analysed.Results:The closet locations of popliteal vessels were at the posteromedial aspect of the femur. The d-H and d-V were 7.38 ± 3.22 mm, and 57.01 ± 11.14 mm, respectively, and were both shorter in women than in men (P < 0.001). Multivariate analysis identified thigh circumference and femoral length as the most influential factors for the d-H and d-V, respectively (P < 0.001). Linear regression demonstrated a strong positive linear correlation between the thigh circumference and the d-H and between the femoral length and the d-V (Pearson’s r = 0.891 and 0.806, respectively [P < 0.001]).Conclusions:The closet location and distance of the popliteal vessels to the femur provide useful information for wire placement during distal femoral fracture surgery while minimising the risk of vascular injury. Given that patients with smaller thigh circumference and shorter femoral length are more likely to have smaller d-H and shorter d-V, respectively, cautious measures should be taken in such cases.Trial registration:retrospectively registered