Fully Automated Determination of Femoral Coordinate System in CT Image Based on Epicondyles

Abstract

We propose a fully automated determination of the femoral coordinates in computerized tomography (CT) imaging based on epicondyles. The challenge point of this paper is that we take up how to calculate the femoral coordinate system (FCS), which is difficult to determine automatically. Our proposed method automatically determines the FCS based on anatomical reference points. We evaluated 10 subjects (six men and four women 28.9 ± 9.3 years old, three left-handed and seven right-handed) who had no history of joint injury. We examined the proposed method by comparing the expert and algorithm. The medial epicondyle was 1.41 ± 0.75 mm (p=0.42>0.05, student’s t test) in positioning accuracy. The lateral epicondyle was 1.36 ± 0.70 mm (p=0.42) in positioning accuracy. The origin was 0.87 ± 0.40 mm (p=0.71). in positioning accuracy. The lateral axis angle accuracy was 0.53 ± 0.84^◦ (p=0.44). In short, the proposed method constructed patient-specific coordinate systems more accurately than expert manual.