Half pins for external fixators
AssigneeOrthex, LLC
InventorsAbraham Lavi, Dror Paley, Victor Lavi
Life of this patent
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Abstract
The invention is a half pin for use in conjunction with external fixators, in which the half pin has a thin hydroxyapatite coating over a substantial portion thereof, a not-sharp hole-finding tip, and a variable pitch pattern in the threaded portion of the half pin. The hydroxyapatite coating must be thin—40-70 microns, deposited by plasma spray—and with limited porosity and pore size, and must extend not only over all the threads of the half pin but also a substantial portion of the unthreaded shaft proximal to the threaded end. The invention also includes a pin cube for use in association with the coated half pins. Wires may also be coated with the hydroxyapatite coating.
Claims8
A half pin for use in an external fixator, the half pin comprising:
- a head end;
- a leading tip at a distal end;
- and
- both an unthreaded shaft and a threaded shaft in between said head end and said leading tip,
- wherein said unthreaded shaft is at least as long as said threaded shaft, and
- wherein said threaded shaft has threads of a first pitch and has threads of a second pitch, said threads of said first pitch and said threads of said second pitch being disposed distally to said unthreaded shaft, said threads of said second pitch being more distally disposed to said unthreaded shaft than said threads of said first pitch, said second pitch being larger than said first pitch, said threads of said first pitch having a uniform first major diameter and a uniform first minor diameter, said threads of said second pitch having a uniform second major diameter, said threads of said second pitch having a first end proximal to said leading tip, wherein said leading tip is unthreaded and said threads of said second pitch comprise the threads closest to said unthreaded leading tip, said threads of said second pitch having a second end proximal to said threads of said first pitch, said threads of said second pitch having a second minor diameter gradually increasing from said first end to said second end.
Dependencies are inferred from the claim text.