Determination of Femoral Neck Angle and Torsion Angle Utilizing a Novel Three-Dimensional Modeling and Analytical Technology Based on CT Datasets

• Published in: PloS one Vol. 11; no. 3; p. e0149480
• Main Authors: Hartel, Maximilian J., Petersik, Andreas, Schmidt, Anne, Kendoff, Daniel, Nüchtern, Jakob, Rueger, Johannes M., Lehmann, Wolfgang, Grossterlinden, Lars G.
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 02.03.2016; Public Library of Science (PLoS)
• Subjects: Adult; Aged; Aged, 80 and over; Biology and Life Sciences; Biomedical materials; Body mass; Body Mass Index; Body size; Datasets; Error analysis; Ethnicity; Female; Femur; Femur Neck - diagnostic imaging; Femur Neck - physiology; Gender; Gender aspects; Hip; Hip joint; Hip Joint - diagnostic imaging; Human error; Humans; Inclination; Joint surgery; Male; Measurement methods; Medicine and Health Sciences; Middle Aged; Minority & ethnic groups; Modelling; Morphometrics (Biology); Morphometry; Neck; Orthopedics; People and Places; Physiological aspects; Plastic surgery; Population; Research and Analysis Methods; Sex differences; Statistics as Topic - methods; Surgical implants; Technology; Technology assessment; Three dimensional analysis; Three dimensional models; Tomography, X-Ray Computed - methods; Torsion; Young Adult; Germany
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0149480

Exact knowledge of femoral neck inclination and torsion angles is important in recognizing, understanding and treating pathologic conditions in the hip joint. However, published results vary widely between different studies, which indicates that there are persistent difficulties in carrying out exact measurements. A three dimensional modeling and analytical technology was used for the analysis of 1070 CT datasets of skeletally mature femurs. Individual femoral neck angles and torsion angles were precisely computed, in order to establish whether gender, age, body mass index and ethnicity influence femoral neck angles and torsion angles. The median femoral neck angle was 122.2° (range 100.1-146.2°, IQR 117.9-125.6°). There are significant gender (female 123.0° vs. male 121.5°; p = 0.007) and ethnic (Asian 123.2° vs. Caucasian 121.9°; p = 0.0009) differences. The median femoral torsion angle was 14.2° (-23.6-48.7°, IQR 7.4-20.4°). There are significant gender differences (female 16.4° vs. male 12.1°; p = 0.0001). Femoral retroversion was found in 7.8% of the subjects. Precise femoral neck and torsion angles were obtained in over one thousand cases. Systematic deviations in measurement due to human error were eliminated by using automated high accuracy morphometric analysis. Small but significant gender and ethnic differences were found in femoral neck and torsion angles.