RESUMEN
Objective:To study the design and fabrication of the sub-ischial compression/release stabilized (CRS) transfemoral prosthetic socket based on 3D reconstructed residual limb. Methods:The magnetic resonance imaging (MRI) of a transfemoral amputee's residual limb was used for 3D construction. The base of the socket was constructed by the surface of the 3D geometry of residual limb in SolidWorks, and then the sketching and swept surface function was applied to create the compression and release structure. The CRS socket was analyzed by finite element method. The simulation was then validated experimentally. Results:The transfemoral CRS socket was successfully constructed in SolidWorks and assembled with the residual limb for finite element modeling. The simulation results showed the residual limb pressure distribution over the CRS socket compression areas. The maximum residual limb pressure was predicted to be 218.5 kPa by the finite element model, and experimentally measured was 239 kPa. The maximum residual limb pressure was within the pain threshold and pain tolerance range, and the patient was satisfied with the socket. Conclusion:This attempt of reconstructing residual limb MRI to design the CRS prosthetic socket provided another way to study the socket behavior in the prosthesis fitting process. The FEM-CAD method can improve the socket design and fitting process with computer simulation to reduce the trial on patients.
RESUMEN
Objective To study the load transfer mechanics between residual limb and prosthetic socket, as well as stress distributions below the residual limb, so as to provide a theoretical basis for designing and optimizing of prosthetic socket and improving the wearing comfort. Methods Aiming at compression-release stabilization （CRS）, the finite element software ABAQUS was used to analyze the stress distribution at the interface between the residual limb and CRS socket. The soft tissues were defined using the Mooney-Rivlin function. The interface pressures and shear stresses between the residual limb and CRS socket during mid-stance were obtained. A three-dimensional finite element model of the patellar tendon bearing (PTB) socket was established, and the results were compared. Results The interface pressures between the residual limb and CRS socket were mainly distributed at lateral tibia, media tibia and popliteal depression regions, which were similar to the main force regions of PTB socket. The mean interface pressures on the end of stump for CRS socket was increased by 19 kPa over PTB socket. Conclusions CRS socket had better breathability and reasonable stress distributions. The stress distribution of biomechanical interface was different due to the different shapes of socket. Therefore, the optimization of prosthetic socket can help to improve the wearing comfort of prosthetic limbs.