Variable angle screws, plates and systems
View Patent ↗The present disclosure relates, according to some embodiments, to orthopedic implantable device technology, and more specifically to variable angle implantable devices, systems, and methods.
1. A variable angle orthopedic screw, the screw comprising:
a threaded shank having an upper end and a tip; and
a head fixed to the upper end of the shank, the head comprising:
a generally cylindrical core of radius (r core ) and with a longitudinal axis,
a single continuous thread encircling the core, the apex of which comprises a thread that defines an outer periphery of radius (r head ), wherein the radius (r head ) peak varies along the length of the thread; and
a thread trough,
wherein the thread has a plurality of indentations and a plurality of thread peaks, wherein the peaks and indentations are spaced apart at regular intervals along the length of the thread, each indentation having a radius (r head-indent ), wherein r core <r head-indent <r head ,
wherein the thread has a minimum radius (r head-min ), wherein r core <r head-min , and
wherein the variable angle screw is operable to engage a threaded hole of an orthopedic plate at a first angle aligned with the central hole axis and at least one other angle.
2. A variable angle orthopedic screw according to claim 1 , wherein the at least one indentation further comprises a plurality of indentations arranged in at least one column parallel or substantially parallel to the longitudinal axis.
3. A variable angle orthopedic screw according to claim 2 , wherein the at least one column further comprises 2 columns, 3 columns, 4 columns, 5 columns, or 6 columns, each parallel or substantially parallel to the longitudinal axis and spaced around the longitudinal axis.
4. A variable angle orthopedic screw according to claim 3 , wherein spaced around the longitudinal axis further comprises spaced uniformly around the longitudinal axis.
5. A variable angle orthopedic screw according to claim 1 , wherein the thread spans the length of the head.
6. A variable angle orthopedic screw according to claim 1 , wherein the thread further comprises one or more turns around the circumference of the core.
7. A variable angle orthopedic screw according to claim 1 , wherein r core is about 25% to about 98% r head , and r head-indent is about 26% to about 99% r head .
8. A variable angle orthopedic screw according to claim 1 , wherein r core is about 25% to about 75% r head , and r head-indent is about 26% to about 90% r head .
9. A variable angle orthopedic screw, the screw comprising:
a threaded shank; and
a head fixed to the shank, the head comprising at least one thread spanning at least one turn around the circumference of the head, the apex of which comprises a thread peak that defines a thread height that varies along the length of the thread, each head thread turn comprising:
a first region having a maximum thread height (h max1 ),
a second region having a maximum thread height (h max2 ),
a third region having a minimum thread height (h min3 ) positioned between the first region and the second region, wherein h max1 >h min3 , h max2 >h min3 , and h min3 >0 for each turn independently,
a fourth region having a maximum thread height (h max4 ), and
a fifth region having a minimum thread height (h min5 ) positioned between the second region and the fourth region, wherein h max2 >h min5 , h max4 >h min5 , and h min5 >0 for each turn independently;
wherein the third regions of each turn are aligned in a column parallel or substantially parallel with the longitudinal axis of the screw; and
wherein the fifth regions of each turn are aligned in a column parallel or substantially parallel with the longitudinal axis of the screw.
10. A variable angle orthopedic screw according to claim 9 , wherein each turn further comprises:
a sixth region having a maximum thread height (h max6 ), and
a seventh region having a minimum thread height (h min7 ) positioned between the fourth region and the sixth region, wherein h max4 >h min7 , h max6 >h min7 , and h min7 >0,
wherein the seventh regions of each turn are aligned in a column parallel or substantially parallel with the longitudinal axis of the screw.
11. A variable angle orthopedic screw according to claim 10 , wherein each turn further comprises:
an eighth region having a maximum thread height (h max8 ), and
a ninth region having a minimum thread height (h min9 ) positioned between the sixth region and the eighth region, wherein h max6 >h min9 , h max8 >h min9 , and h min9 >0,
wherein the ninth regions of each turn are aligned in a column parallel or substantially parallel with the longitudinal axis of the screw.
12. A variable angle orthopedic screw according to claim 11 , wherein h min3 ≈h min5 ≈h min7 ≈h min9 .
13. A variable angle orthopedic screw according to claim 12 , wherein h max1 ≈h max2 ≈h max4 ≈h max6 ≈h max8 .
14. A variable angle orthopedic screw according to claim 13 , wherein minimum thread height (h min3 ) is about 1% to about 80% of maximum thread height (h max1 ).
15. A variable angle orthopedic screw according to claim 13 , wherein minimum thread height (h min3 ) is about 5% to about 60% of maximum thread height (h max1 ).
16. A variable angle orthopedic screw according to claim 11 , wherein h max1 ≈h max2 ≈h max4 ≈h max6 ≈h max8 .
17. A variable angle orthopedic screw according to claim 11 , wherein the circumferential extent of the first region, the second region, the fourth region and the sixth region total more than 180°,
the circumferential extent of the third region, the fifth region, and the seventh region total less than 180°, and
circumferential extent of the first, second, third, fourth, fifth, sixth, and seventh regions total 360° or less.
18. A variable angle orthopedic screw according to claim 11 , wherein the circumferential extent of the first region, the second region, the fourth region and the sixth region total more than 210°,
the circumferential extent of the third region, the fifth region, and the seventh region total less than 150°, and
circumferential extent of the first, second, third, fourth, fifth, sixth, and seventh regions total 360° or less.
19. A variable angle orthopedic screw according to claim 11 , wherein the thread further comprises at least one of the following transitions from one region to the next region: step-wise transitions, graded transitions, and smooth transitions.
20. A variable angle orthopedic screw according to claim 9 , wherein each thread minimum is from about 1% to about 90% of the adjacent thread maxima.
21. A variable angle orthopedic screw according to claim 9 , wherein each thread minimum is from about 5% to about 80% of the adjacent thread maxima.
22. A variable angle orthopedic screw according to claim 21 , wherein the at least two turns around the circumference of the head further comprises at least three turns around the circumference of the head.
23. A variable angle orthopedic screw according to claim 9 , wherein the at least one thread spanning at least one turn around the circumference of the head further comprises at least two turns around the circumference of the head.
24. A variable angle orthopedic screw according to claim 9 , wherein the head has a generally cylindrical shape.
25. A variable angle orthopedic screw, the screw comprising:
a variable angle head comprising at least one thread spanning at least a first turn and a second turn around the circumference of the head, wherein the apex of the thread comprises a thread peak that defines a thread height that varies along the length of the thread,
wherein the first turn comprises:
a first region having a maximum thread height (h max1-1 ),
a second region having a maximum thread height (h max1-2 ), and
a third region having a minimum thread height (h min1-3 ) positioned between the first region and the second region, wherein h max1-1 >h min1-3 , h max1-2 >h min1-3 , and h min1-3 >0,
wherein the second turn comprises:
a first region having a maximum thread height (h max2-1 ),
a second region having a maximum thread height (h max2-2 ), and
a third region having a minimum thread height (h min2-3 ) positioned between the first region and the second region, wherein h max2-1 >h min2-3 , h max2-2 >h min2-3 , and h min2-3 >0,
wherein the third region of the first turn and the third region of the second turn are aligned in a column parallel or substantially parallel with the longitudinal axis of the head.
26. A variable angle orthopedic screw according to claim 25 , wherein h max1-1 ≈h max1-2 .
27. A variable angle orthopedic screw according to claim 25 , wherein minimum thread height (h min1-3 ) is about 1% to about 80% of maximum thread height (h max1-1 ).