Methods of manufacturing and designing a lightweight femoral stem for hip implants
Inventors
Xue, Zhenyu • Xu, Kai • Zhang, Jing
Assignees
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Publication Number
US-10813766-B2
Publication Date
2020-10-27
Expiration Date
Abstract
A method of manufacturing a femoral stem for a hip implant includes forming a femoral neck extending from a proximal end of the femoral stem towards a distal end of the femoral stem, forming an upper section connected to and extending from the femoral neck towards the distal end of the femoral stem, and forming a lower section connected to and extending from the upper section to the distal end of the femoral stem. Further, a method for designing a femoral stem for a hip implant includes generating a customized femoral stem model to match an information of a patient, generating at least one proximal-distal solid rib in the upper section, calculating density and stress distributions for an open lattice and for a closed lattice, and selecting a unit cell type and a pore size for the open lattice and the closed lattice to match a density and/or a stiffness of the patient's femur.
Core Innovation
The invention relates to lightweight, patient-customizable femoral stems for hip implants formed by additive manufacturing, where the femoral stem includes a femoral neck, an upper section connected to and extending from the femoral neck, and a lower section connected to and extending from the upper section toward the distal end. The upper section comprises at least one proximal distal solid rib flanked by an open lattice, and the upper section further comprises a transverse plate that divides the open lattice into a first portion and a second portion with at least one of a different unit cell type and a different pore size.
The lower section comprises a closed lattice enclosed in a solid skin. The open lattice and the closed lattice are configured with different lattice characteristics and are combined with proximal distal solid ribs and segmentation of the open lattice by a transverse plate, enabling different unit cell types and/or pore sizes across portions of the open lattice while also enclosing the lower closed lattice in a solid skin.
The invention further discloses a designing workflow that generates a customized femoral stem model to match information of a patient. Density and stress distributions are calculated for the open lattice flanking the at least one proximal distal solid rib and for the closed lattice in the lower section, and lattice unit cell type(s) and pore size(s) are selected to match a density and/or stiffness of the patient's femur.
Claims Coverage
The partial content includes two independent claims. The inventive features are directed to an additive manufacturing femoral stem architecture using open and closed lattices separated or segmented with ribs and a transverse plate, and to a design method that generates a patient-matched customized femoral stem model and selects lattice parameters using density and stress distributions to match femur density and/or stiffness.
Femoral stem manufacturing with rib-flanked open lattice and closed lattice in solid skin
forming a femoral neck; forming an upper section connected to and extending from the femoral neck toward the distal end, the upper section comprising at least one proximal distal solid rib flanked by an open lattice and a transverse plate dividing the open lattice into a first portion and a second portion different in at least one of a unit cell type and a pore size; and forming a lower section connected to and extending from the upper section toward the distal end, the lower section comprising a closed lattice enclosed in a solid skin.
Patient-matched femoral stem design using density and stress distributions
generating a customized femoral stem model to match information of a patient, where the model comprises a femoral neck, an upper section comprising an open lattice with a transverse plate dividing the open lattice into first and second portions different in at least one of a unit cell type and a pore size, and a lower section comprising a closed lattice enclosed in a solid skin; generating at least one proximal distal solid rib in the upper section; calculating density and stress distributions for the open lattice flanking the at least one proximal distal solid rib and for the closed lattice; and selecting a first lattice unit cell type and a first pore size for the open lattice and a second lattice unit cell type and a second pore size for the closed lattice to match a density and/or a stiffness of the patient's femur.
Across the independent claims, the core coverage is an engineered femoral stem architecture that combines proximal distal solid ribs, an open lattice segmented by a transverse plate into regions with different unit cell type and/or pore size, and a lower closed lattice enclosed in a solid skin, together with a patient-matched design process that uses calculated density and stress distributions to select lattice unit cell types and pore sizes to match the patient's femur density and/or stiffness.
Stated Advantages
Not explicitly described in patent.
Documented Applications
Not explicitly described in patent.
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