A device for determining an anteversion angle (α) of a femoral shaft of a femur, comprising: - a provision unit, and - a processing unit, wherein the provision unit is configured to provide image data of the femur, wherein the processing unit is configured to determine a longitudinal shaft axis extending through the femoral shaft based on the image data, wherein the processing unit is further configured to determine at least two landmarks of the femur based on the image data, wherein each landmark corresponds to a lowest point on each condyle (41, 42), wherein the lowest point is the point of the condyle (41, 42) where the tangent (T1, T2) through the lowest point has the largest possible distance from the shaft axis, wherein the processing unit is further configured to place a tangent (T1, T2) through each landmark parallel to the shaft axis, and wherein the processing unit is configured to determine the anteversion angle (α) of the femoral shaft based on the tangents (T1, T2) and the shaft axis of the femoral shaft, wherein the anteversion angle (α) is determined based on an intersection of a first plane and a second plane, wherein the first plane is defined by the tangents (T1, T2) and the second plane is defined by the shaft axis and a centre of a femur head of the femur, and wherein the processing unit is further configured to determine a distance (d) perpendicular between the tangents (T1, T2) and to output an imaging instruction in case the distance (d) exceeds a predefined threshold, wherein the imaging instruction is configured to obtain new image data. - a provision unit, and - a processing unit, wherein the provision unit is configured to provide image data of the femur, wherein the processing unit is configured to determine a longitudinal shaft axis extending through the femoral shaft based on the image data, wherein the processing unit is further configured to determine at least two landmarks of the femur based on the image data, wherein each landmark corresponds to a lowest point on each condyle (41, 42), wherein the lowest point is the point of the condyle (41, 42) where the tangent (T1, T2) through the lowest point has the largest possible distance from the shaft axis, wherein the processing unit is further configured to place a tangent (T1, T2) through each landmark parallel to the shaft axis, and wherein the processing unit is configured to determine the anteversion angle (α) of the femoral shaft based on the tangents (T1, T2) and the shaft axis of the femoral shaft, wherein the anteversion angle (α) is determined based on an intersection of a first plane and a second plane, wherein the first plane is defined by the tangents (T1, T2) and the second plane is defined by the shaft axis and a centre of a femur head of the femur, and wherein the processing unit is further configured to determine a distance (d) perpendicular between the tangents (T1, T2) and to output an imaging instruction in case the distance (d) exceeds a predefined threshold, wherein the imaging instruction is configured to obtain new image data. wherein the provision unit is configured to provide image data of the femur, wherein the processing unit is configured to determine a longitudinal shaft axis extending through the femoral shaft based on the image data, wherein the processing unit is further configured to determine at least two landmarks of the femur based on the image data, wherein each landmark corresponds to a lowest point on each condyle (41, 42), wherein the lowest point is the point of the condyle (41, 42) where the tangent (T1, T2) through the lowest point has the largest possible distance from the shaft axis, wherein the processing unit is further configured to place a tangent (T1, T2) through each landmark parallel to the shaft axis, and wherein the processing unit is configured to determine the anteversion angle (α) of the femoral shaft based on the tangents (T1, T2) and the shaft axis of the femoral shaft, wherein the anteversion angle (α) is determined based on an intersection of a first plane and a second plane, wherein the first plane is defined by the tangents (T1, T2) and the second plane is defined by the shaft axis and a centre of a femur head of the femur, and wherein the processing unit is further configured to determine a distance (d) perpendicular between the tangents (T1, T2) and to output an imaging instruction in case the distance (d) exceeds a predefined threshold, wherein the imaging instruction is configured to obtain new image data.