Granted Patent B2

US 12,285,221 · App. 18/848,296 · Granted Apr 29, 2025

Inventors: Carolina Dos Santos Raposo (Coimbra, PT); João Pedro De Almeida Barreto (Coimbra, PT); Michel Gonçalves Almeida Antunes (Coimbra, PT)

Assignees: SMITH & NEPHEW, INC; SMITH & NEPHEW ORTHOPAEDICS AG; SMITH & NEPHEW ASIA PACIFIC PTE. LIMITED

A61B34/10A61B2034/105

Abstract

Claims (83)

1. A computer-implemented method comprising:

identifying, by a device, a three-dimensional (3D) model of a femur;

analyzing, by a device, the 3D model, and determining a pair of points on the femur that have normal vectors that are orthogonal to a vector joining the pair of points;

analyzing, by a device, the vector, and determining a sagittal direction;

further analyzing, by the device, the 3D model based on the determined sagittal direction, and generating an intersection map of the 3D model, the intersection map comprising information related to a curve value of an intercondylar region;

determining, by a device, a Blumensaat line based on the intersection map;

analyzing, by the device, the intersection map in accordance with the Blumensaat line, and determining a Bernard-Hertel (BH) grid, the BH grid comprising an area that encloses condyles when the femur is subject to a lateral view; and

placing, by a device, a digital representation of the BH grid as an overlay of the 3D model.

2. The computer-implemented method of claim 1 , further comprising:

determining values for the pair of points and each normal vector;

clustering the determined values; and

determining a median value based on the clustering, wherein the determined sagittal direction corresponds to the median value.

3. The computer-implemented method of claim 1 , further comprising:

executing, by a device, an estimation model; and

determining the sagittal direction based on an output of the estimation model.

4. The computer-implemented method of claim 1 , further comprising:

identifying lateral and medial condyles; and

determining, based on the identified lateral and medial condyles, a lateral-medial orientation of the sagittal direction.

5. The computer-implemented method of claim 4 , further comprising refining the sagittal direction based on adjustments of an outer border of the lateral and medial condyles.

6. The computer-implemented method of claim 1 , further comprising backprojecting the BH grid to the 3D model, the BH grid being a two-dimensional (2D) model, wherein the backprojection is based on a sectioning plane defined by the sagittal direction and Blumensaat's line.

7. The computer-implemented method of claim 1 , further comprising:

backprojecting points on the intersection map to points on the 3D model, wherein the points on the intersection map are two-dimensional (2D); and

obtaining a sectioning plane of the 3D model based on the sagittal direction; and

determining an axial direction via circle fitting.

8. The computer-implemented method of claim 1 , further comprising:

determining contours of the femur based on a sagittal view of the femur, the sagittal view being obtained through 2D projection along the sagittal direction;

searching for circles that are tangent to the contours in two points; and

estimating a line that joins respective centers of the circles, wherein the estimated line provides information related to an axial direction.

9. The computer-implemented method of claim 1 , further comprising:

analyzing, based on the sagittal direction, the femur, and determining a sagittal view of the femur;

determining, based on the sagittal view, an axial direction; and

determining a coronal direction based on a cross-product of the sagittal and axial directions.

10. The computer-implemented method of claim 9 , further comprising determining an anatomical reference frame (ARF) of the femur based on the sagittal, axial and coronal directions.

11. The computer-implemented method of claim 1 , further comprising:

identifying an orthographic projection of the femur;

identifying, based on the orthographic projection, a set of projection rays within the 3D model related to the femur;

determining a set of intersections corresponding to the set of projection rays, wherein the intersection map comprises information related to the set of intersections.

12. The computer-implemented method of claim 11 , further comprising:

analyzing, via edge detection analysis, the set of intersections; and

determining the curve value of the intercondylar region based on the edge detection analysis, wherein the Blumensaat line is tangential to a curve associated with the curve value.

13. A non-transitory computer-readable storage medium tangibly encoded with computer-executable instructions, that when executed by one or more devices, cause the one or more devices to:

identify a three-dimensional (3D) model of a femur;

analyzing the 3D model, and determine a pair of points on the femur that have normal vectors that are orthogonal to a vector joining the pair of points;

analyze the vector, and determine a sagittal direction;

further analyze the 3D model based on the sagittal direction, and generate an intersection map of the 3D model, the intersection map comprising information related to a curve value of an intercondylar region;

determine a Blumensaat line based on the intersection map;

analyze the intersection map in accordance with the Blumensaat line, and determine a Bernard-Hertel (BH) grid, the BH grid comprising an area that encloses condyles when the femur is subject to a lateral view; and

place a digital representation of the BH grid as an overlay of the 3D model.

14. The non-transitory computer-readable storage medium of claim 13 , wherein the instructions further cause the one or more devices to:

determine values for the pair of points and each normal vector;

cluster the values; and

determine a median value based on the clustering, wherein the sagittal direction corresponds to the median value.

15. The non-transitory computer-readable storage medium of claim 13 , wherein the instructions further cause the one or more devices to:

identify lateral and medial condyles;

determine, based on the identified lateral and medial condyles, a lateral-medial orientation of the sagittal direction; and

refine the sagittal direction based on adjustments of an outer border of the lateral and medial condyles.

16. The non-transitory computer-readable storage medium of claim 13 , wherein the instructions further cause the one or more devices to:

backproject points on the intersection map to points on the 3D model, wherein the points on the intersection map are two-dimensional (2D);

obtain a sectioning plane of the 3D model based on the sagittal direction; and

determine an axial direction via circle fitting.

17. The non-transitory computer-readable storage medium of claim 13 , wherein the instructions further cause the one or more devices to:

determine contours of the femur based on a sagittal view of the femur, the sagittal view being obtained through 2D projection along the sagittal direction;

search for circles that are tangent to the contours in two points; and

estimate a line that joins respective centers of the circles, wherein the estimated line provides information related to an axial direction.

18. The non-transitory computer-readable storage medium of claim 13 , wherein the instructions further cause the one or more devices to:

analyze, based on the sagittal direction, the femur, and determine a sagittal view of the femur;

determine, based on the sagittal view, an axial direction;

determine a coronal direction based on a cross-product of the sagittal and axial directions; and

determine an anatomical reference frame (ARF) of the femur based on the sagittal, axial and coronal directions.

19. A device comprising:

one or more processors configured to:

identify a three-dimensional (3D) model of a femur;

analyze the 3D model, and determine a pair of points on the femur that have normal vectors that are orthogonal to a vector joining the pair of points;

analyze the vector, and determine a sagittal direction;

further analyze the 3D model based on the determined sagittal direction, and generate an intersection map of the 3D model, the intersection map comprising information related to a curve value of an intercondylar region;

determine a Blumensaat line based on the intersection map;

analyze the intersection map in accordance with the Blumensaat line, and determine a Bernard-Hertel (BH) grid, the BH grid comprising an area that encloses condyles when the femur is subject to a lateral view; and

place a digital representation of the BH grid as an overlay of the 3D model.

20. The device of claim 19 , wherein the one or more processors are further configured to:

analyze, based on the sagittal direction, the femur, and determining a sagittal view of the femur;

determine, based on the sagittal view, an axial direction;

determining a coronal direction based on a cross-product of the sagittal and axial directions; and

determine an anatomical reference frame (ARF) of the femur based on the sagittal, axial and coronal directions.

Assignments (2)

Continuity (2)

References Cited (17)