Volumetric measurement of femoral head necrosis based on reverse engineering techniques

Abstract

Objective To assess the accuracy of volumetric measurement of femoral head necrosis based on reverse engineering techniques.Methods From January 2011 to November 2011,we treated 16 patients with femoral head necrosis (20 hips).They were 10 men and 6 women,with an average age of 65.7 years.Six patients (8 hips) were afflicted with hormonal necrosis,4 patients (5 hips) with alcoholic necrosis,4 patients (4 hips) with idiopathic necrosis,and 2 patients (3 hips) with traumatic necrosis.The volume of necrosis was measured by the following 2 ways:1) The DICOM CT data of the femoral head necrosis were put into software Mimics 10.1 for 3D reconstruction of the necrotic region and the femoral head using reverse engineering techniques.Next the volumes of necrotic regions and femoral heads were calculated using self-designed software.2) The actual volumes of necrotic regions and femoral heads were calculated manually by displacing them with water.Results The mean volumes of femoral heads measured by computer and by hand were respectively 56,125.37 ±4,681.73 mm3 and 56,271.05 ±4,539.08 mm3; the mean volumes of necrotic regions measured by computer and by hand were respectively 25,256.42 ± 3,748.91 mm3 and 25,884.68 ± 3,499.75 mm3.There were no significant differences between the 2 measurement methods (P ＞0.05).Conclusion Volumetric measurement of femoral head necrosis based on reverse engineering techniques is accurate and should be recommended. Key words: Femur head necrosis; Image processing, computer assisted; Volume