Bone plate
A bone plate including a long-plate-shaped main section to be disposed on a side surface of a diaphysis, a transverse section to be disposed on the side surface of an epiphysis, a coupling section coupling the transverse section and the main section to each other. The main section is twisted relative to the transverse section around an axis parallel to a longitudinal axis of the main section. when the bone plate is viewed in a transverse direction of the main section, the bone plate has a shape in conformity to the shin bone such that the coupling section is inclined relative to a longitudinal direction of the main section and the main section and the transverse section are bent to have a cranked shape in which the main section and the transverse section are offset relative to each other in a thickness direction of the bone plate.
1 . A bone plate for a tibial condylar valgus osteotomy, which is configured to be applied to an inner side surface of a shin bone where an inner side surface of an epiphysis protrudes relative to an inner side surface of a diaphysis, the bone plate being configured to be fixed to the inner side surface of the shin bone by bone fixation members, and the bone plate comprising:
a long-plate-shaped main section that is configured to be disposed on the inner side surface of the diaphysis and that has one or more through-holes into which the bone fixation members are inserted;
a transverse section that is configured to be disposed on the inner side surface of the epiphysis and that is disposed at an end side of the main section and also that has one or more through-holes into which the bone fixation members are inserted; and
a coupling section coupling the transverse section and the main section to each other,
wherein the main section is twisted relative to the transverse section around an axis that is parallel to a longitudinal axis of the main section,
wherein, when the bone plate is viewed in a transverse direction of the main section, the bone plate is configured to conform to the inner side surface of the shin bone such that the coupling section is inclined relative to a longitudinal direction of the main section and the main section and the transverse section are bent to have a cranked shape in which the main section and the transverse section are offset relative to each other in a thickness direction of the bone plate,
wherein a twist angle of the transverse section relative to the main section around the axis ranges between 8° and 30°, and
wherein an offset amount between the main section and the transverse section in the thickness direction is 9 mm±3 mm.
2 . The bone plate according to claim 1 , wherein the transverse section extends in a direction configured to correspond to a rear side of the shin bone relative to the main section and in the direction intersects the longitudinal direction of the main section, and the traverse section curves in another direction intersecting the longitudinal direction of the main section, and
wherein, when the transverse section is viewed in a shorter-dimension-side axis direction of the traverse section, a lower surface of the transverse section that is configured to be disposed on the inner side surface of the shin bone extends through two circular arcs whose radiuses of curvature are 20 mm and 40 mm and each of which extends through each of opposite longitudinal ends of the transverse section.
3 . The bone plate according to claim 2 , wherein the transverse section comprises two or more of the through-holes arranged in a longitudinal direction of the transverse section, and
wherein center axes of the two or more through-holes are configured to incline toward a front side of the epiphysis in an insertion direction of the bone fixation members and the center axes are configured to incline at an equal angle toward a distal side of the shin bone in the insertion direction of the bone fixation member.
4 . The bone plate according to claim 1 , wherein, in a vertical section of the bone plate taken along a shorter-dimension-side axis of the transverse section, an angle in the thickness direction of the bone plate between the shorter-dimension-side axis of the transverse section and a longitudinal axis of the coupling section is 155°±10°, an angle in the thickness direction of the bone-plate between the longitudinal axis of the coupling section and the longitudinal axis of the main section is 160°±10°, and a length between a center of a most-proximal through-hole in the main section and a center of a most-distal through-hole in the transverse section in a direction extending along the coupling section is 38.5 mm±5 mm.
5 . The bone plate according to claim 1 , wherein, when the transverse section is viewed in a shorter-dimension-side axis direction of the transverse section, center axes of all the through-holes in the transverse section are oriented in directions different from each other.
6 . The bone plate according to claim 5 , wherein the transverse section has a first through-hole, a second through-hole, and a third through-hole that are arranged sequentially in a longitudinal direction of the transverse section from a side configured to be arranged at a front side of the epiphysis toward a side configured to be arranged at a rear side of the epiphysis,
wherein a center axis of the first through-hole is inclined at 23°±5° relative to a normal to a tangent plane of a lower surface of the first through-hole,
wherein a center axis of the second through-hole is inclined at 8.5°±5° relative to a normal to a tangent plane of a lower surface of the second through-hole, and
wherein a center axis of the third through-hole is inclined at 9.5°±5° relative to a normal to a tangent plane of a lower surface of the third through-hole.
7 . The bone plate according to claim 1 , wherein the transverse section comprises three of the through-holes, and
wherein center axes of the three through-holes are inclined relative to one another such that three of the bone fixation members extending through the three through-holes come in contact with one another inside the epiphysis.
8 . The bone plate according to claim 1 , wherein a distance between one of the through-holes in the main section that is located closest to the transverse section and one of the through-holes in the transverse section that is located closest to the main section ranges between 28.5 mm and 45.0 mm.
9 . The bone plate according to claim 1 , wherein the main section has a width ranging between 11 mm and 18 mm,
wherein the transverse section has a width ranging between 20 mm and 40 mm,
wherein the coupling section has a width ranging between 12 mm and 25 mm,
wherein the bone plate has a thickness of 3 mm±1 mm, and
wherein the bone plate has a shape that satisfies conditions indicated below in a vertical section of the bone plate taken along a shorter-dimension-side axis of the transverse section:
33.5 mm≤L2≤43.5 mm
54 mm≤L1+L2≤64 mm
104 mm≤L1+L2+L3≤135 mm
wherein
L 1 denotes a length between a proximal end of the transverse section and a center axis of a most-distal through-hole in the transverse section,
L 2 denotes a length between the center axis of the most-distal through-hole in the transverse section and a center axis of a most-proximal through-hole in the main section, and
L 3 denotes a length between the center axis of the most-proximal through-hole in the main section and a distal end of the main section.
10 . The bone plate according to claim 1 , wherein all the through-holes in the transverse section are disposed at a side configured to be arranged at a rear side of the shin bone relative to the longitudinal axis of the main section, and
wherein, when the bone plate is viewed along the longitudinal axis of the main section, extensions of center axes of at least two of the through-holes in the main section and extensions of center axes of at least two of the through-holes in the transverse section intersect with each other between opposite ends of the bone plate in the transverse direction of the main section.
11 . A bone plate configured to be applied to an inner side surface of a shin bone where an inner side surface of an epiphysis protrudes relative to an inner side surface of a diaphysis, the bone plate being configured to be fixed to the inner side surface of the shin bone by bone fixation members, and the bone plate comprising:
a long-plate-shaped main section that is configured to be disposed on the inner side surface of the diaphysis and that has one or more through-holes into which the bone fixation members are inserted;
a transverse section that is configured to be disposed on the inner side surface of the epiphysis and that is disposed at an end side of the main section and also that has one or more through-holes into which the bone fixation members are inserted; and
a coupling section coupling the transverse section and the main section to each other,
wherein the main section is twisted relative to the transverse section around an axis that is parallel to a longitudinal axis of the main section,
wherein, when the bone plate is viewed in a transverse direction of the main section, the bone plate is configured to conform to the inner side surface of the shin bone such that the coupling section is inclined relative to a longitudinal direction of the main section and the main section and the transverse section are bent to have a cranked shape in which the main section and the transverse section are offset relative to each other in a thickness direction of the bone plate,
wherein the bone plate comprises a lower surface configured to be disposed on the inner side surface of the shin bone and an upper surface that is configured to be opposed to the lower surface and that is configured to be disposed opposite the inner side surface of the shin bone,
wherein a center axis of at least one of the through-holes in each of the main section and the transverse section is inclined relative to a normal to a tangent plane of the upper surface,
wherein the upper surface has a protrusion provided around the at least one through-hole, and
wherein the protrusion is provided at a side where an angle formed between the center axis and the tangent plane is an obtuse angle.
12 . The bone plate according to claim 11 , wherein the center axis of the at least one through-hole is inclined at 5° to 25° relative to the normal,
wherein a head of the bone fixation member disposed in the through-hole has an outer diameter ranging between 4.5 mm and 8 mm,
wherein a maximum width of the protrusion in a direction intersecting the normal is 12 mm or smaller, and
wherein a maximum protruding amount of the protrusion from the upper surface surrounding the protrusion is 1.2 mm or smaller.
13 . A bone plate for a tibial condylar valgus osteotomy, which is configured to be applied to an inner side surface of a shin bone where an inner side surface of an epiphysis protrudes relative to an inner side surface of a diaphysis, the bone plate being configured to be fixed to the inner side surface of the shin bone by bone fixation members, and the bone plate comprising:
a long-plate-shaped main section that is configured to be disposed on the inner side surface of the diaphysis and that has one or more through-holes into which the bone fixation members are inserted;
a transverse section that is configured to be disposed on the inner side surface of the epiphysis and that is disposed at an end side of the main section and also that has one or more through-holes into which the bone fixation members are inserted; and
a coupling section coupling the transverse section and the main section to each other,
wherein the main section is twisted relative to the transverse section around an axis that is parallel to a longitudinal axis of the main section,
wherein, when the bone plate is viewed in a transverse direction of the main section, the bone plate is configured to conform to the inner side surface of the shin bone such that the coupling section is inclined relative to a longitudinal direction of the main section and the main section and the transverse section are bent to have a cranked shape in which the main section and the transverse section are offset relative to each other in a thickness direction of the bone plate,
wherein a twist angle of the transverse section relative to the main section around the axis ranges between 8° and 30°,
wherein an offset amount between the main section and the transverse section in the thickness direction is 9 mm±3 mm, and
wherein, in a vertical section of the bone plate taken along a shorter-dimension-side axis of the transverse section, an angle in a bone-plate-thickness direction between the shorter-dimension-side axis of the transverse section and a longitudinal axis of the coupling section is 155°±10°, an angle in the bone-plate-thickness direction between the longitudinal axis of the coupling section and the longitudinal axis of the main section is 160°±10°.