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Objective To study topological structure of a new type of three-dimensional (3D) printed height increasing insoles for leg length discrepancy (LLD) and its effect on biomechanics of lower limbs. Methods Topological structure for middle and rear part of the insole was optimized by solid isotropic microstructures with penalization (SIMP), the force was loaded and the boundary conditions were set according to force area of the insole, and the height increasing insole with thermoplastic polyurethanes (TPU) materials was printed by selected laser sintering (SLS). The insoles were used in 9 patients with LLD, visual analogue scale (VAS) and Maryland foot function scores were used to compare pain and foot function changes of patients before and after using the insole, and the 3D gait analysis system was used to compare spatiotemporal parameters and vertical ground reaction force (vGRF) of both lower limbs. Result sAfter the patient wore 3D printed insole, VAS scores decreased, Maryland foot function scores increased, vGRF of both lower limbs decreased, and the difference of cadence, stance phase and swing phase in both lower limbs decreased. Conclusions The 3D printed height increasing insole after topology optimization can improve coordination of lower limb movement, reduce ground impact, relieve pain and improve foot function, thus providing an effective personalized orthopedic plan for LLD treatment in clinic.
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Objective@#To investigate the feasibility of an accuracy evaluation method for 3D reconstructed bone model based on 3D reconstruction software Arigin3D Pro.@*Methods@#Pig femurs were used as solid models which were scanned by CT and MRI respectively. The scan data were imported into software Arigin3D Pro for 3D model reconstruction by 3 operators with different reconstruction experience (≤1 year, 2 to 3 years, and ≥4 years, respectively). Each operator reconstructed the femurs 3 times and in each reconstruction measured the diameter of the femoral head, the length of the femur and the width of the knee joint at the distal end of the femur 3 times respectively using software Geomagic Wrap. The above parameters of the solid models were measured using a vernier caliper. The parameter values of reconstructed models and solid models were compared and the differences were analyzed.@*Results@#The measurements by Geomagic Wrap showed deviations between the CT and MRI reconstruction models and the solid models, and the maximum deviation percentages were 1.47% and 1.08%, respectively. The percentages of intra-operater difference ranged from 0.29% to 1.53%; the 3D models reconstructed by operators with different reconstruction experience were not identical.@*Conclusions@#It is a feasible accuracy evaluation method to compare key parameters between the 3D bone model reconstructed by software Arigin3D Pro and the real animal bone. The deviations of 3D reconstructed bone model based on CT and MRI images are acceptable. The accuracy of 3D bone construction is related to the difference in operators.
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Objective To investigate the feasibility of an accuracy evaluation method for 3D reconstructed bone model based on 3D reconstruction software Arigin3D Pro.Methods Pig femurs were used as solid models which were scanned by CT and MRI respectively.The scan data were imported into software Arigin3D Pro for 3D model reconstruction by 3 operators with different reconstruction experience (≤1 year,2 to 3 years,and ≥4 years,respectively).Each operator reconstructed the femurs 3 times and in each reconstruction measured the diameter of the femoral head,the length of the femur and the width of the knee joint at the distal end of the femur 3 times respectively using software Geomagic Wrap.The above parameters of the solid models were measured using a vernier caliper.The parameter values of reconstructed models and solid models were compared and the differences were analyzed.Results The measurements by Geomagic Wrap showed deviations between the CT and MRI reconstruction models and the solid models,and the maximum deviation percentages were 1.47％ and 1.08％,respectively.The percentages of intra-operater difference ranged from 0.29％ to 1.53％;the 3D models reconstructed by operators with different reconstruction experience were not identical.Conclusions It is a feasible accuracy evaluation method to compare key parameters between the 3D bone model reconstructed by software Arigin3D Pro and the real animal bone.The deviations of 3D reconstructed bone model based on CT and MR1 images are acceptable.The accuracy of 3D bone construction is related to the difference in operators.
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Objective To establish a finite element model of rotator cuff which can be used to simulate the rotator cuff injury and to evaluate the biomechanical effects of rotator cuff surgery.Methods The Dicom CT images of the right shoulder of a Chinese healthy volunteer were used to establish models of the scapula,humerus and clavicle.The rotator cuff structures were separated and modeled based on the MRI images and anatomical knowledge.After the rotator cuff model was introduced into the finite element analysis software Abaqus 6.12,the anatomical positions were simulated when the shoulder was at 30° internal rotation,30° external rotation,30° abduction,30° adduction,30° flexion and 30° extension.Results When the shoulder was in 30° flexion,the average stress was 52.2 kPa on the supraspinatus,223.0 kPa on the inffaspinatus and the teres minor,and 90.4 kPa on the subscapularis.When the shoulder was in 30° extension,the average stress was 105.0 kPa on the supraspinatus,78.2 kPa on the infraspinatus and the teres minor,and 55.7 kPa on the subscapularis,indicating that the muscle and tendon of the supraspinatus was subjected to greater stress and the humerus and the scapula produced less stress compared with the shoulder in 30° flexion.Conclusion Since our finite element model of the rotator cuff can simulate common activities of the shoulder joint and obtain stress values of the corresponding rotator cuff muscles,it can be used in simulation of rotator cuff injury and its surgery.