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Publication Number
US-12029459-B2
Publication Date
2024-07-09
Expiration Date
Abstract
The present disclosure describes a bone screw for use in orthopedic procedures. The bone screw includes a shank portion having a helical thread and a head portion also having a helical thread. The head portion has a reverse frustoconical shape, with the conical taper decreasing in the proximal direction.
Core Innovation
The disclosed invention relates to an orthopedic bone screw for an anatomical target site in a human patient. The screw includes a head, a neck, and a shank that are colinear along a longitudinal axis extending between a proximal end of the head and a distal end of the shank. The head includes a reverse frustoconical cross-sectional shape with a narrow base at the proximal end and a wide base at the distal end, with a curved lateral surface tapered relative to the longitudinal axis to define a reverse taper angle.
At least one helical thread extends from the narrow base of the head to the wide base of the head. The helical thread on the head has a thread surface area and a diameter that defines a major diameter of the head, and the major diameter of the head increases or remains constant from the wide base to the narrow base to increase the thread surface area in a distal to proximal direction. The helical thread is configured to contact a bone forming part of the anatomical target site when the head is implanted during use, to thereby enhance the purchase of the head into the bone.
The screw further includes a drive feature dimensioned to cooperate with an instrument such that the head, shank, and neck may be rotated about the longitudinal axis to drive the shank, neck, and head into the anatomical target of a patient. The shank includes a curved lateral surface with at least one helical thread extending from a proximal end of the shank toward a distal end of the shank, the at least one helical thread including at least one pitch.
Multiple embodiments further refine the head and shank geometry and thread parameters, including proximal-direction taper angle ranges and thread pitch configurations, and they include compression-neutral screw and compression screw configurations based on relationships between head-thread pitch and shank-thread pitch. Additional embodiments include optional cutting flutes or reverse cutting flutes in the helical thread of the head, and driver recess and head surface geometries that reduce or avoid head protrusion when implanted at angles.
Claims Coverage
The document contains one independent claim (clm-00001). It sets out multiple inventive features centered on a colinear head-neck-shank orthopedic screw with a reverse frustoconical threaded head, a pitch-defined helical-threaded shank, and a drive feature for rotation about a longitudinal axis; dependent claims refine quantitative geometry and define compression-neutral versus compression configurations through pitch relationships and additional thread and fluting structures.
Colinear head-neck-shank rotatable orthopedic screw
A screw for orthopedic surgery at an anatomical target site in a human patient, comprising a head, a shank, and a neck extending between the head and the shank, wherein the head, neck and shank are colinear along a longitudinal axis extending between a proximal end of the head and a distal end of the shank; and a drive feature dimensioned to cooperate with an instrument such that the head, shank, and neck may be rotated about the longitudinal axis in order to drive the shank, neck and head into an anatomical target of a patient.
Reverse frustoconical threaded head to enhance purchase
A head including a reverse frustoconical cross-sectional shape defined by a narrow base at the proximal end of the head, a wide base at the distal end of the head, a minor diameter that increases from the narrow base to the wide base, and a curved lateral surface extending between the narrow base and the wide base that is tapered relative to the longitudinal axis to define a reverse taper angle; and at least one helical thread extending from the narrow base of the head to the wide base of the head, wherein the helical thread is configured to contact a bone forming part of the anatomical target site when the head is implanted during use to thereby enhance the purchase of the head into the bone.
Defined head major diameter thread surface area distribution
At least one helical thread having a thread surface area and a diameter that defines a major diameter of the head, wherein the major diameter of the head at least one of increases and remains constant from the wide base to the narrow base to increase the thread surface area in a distal to proximal direction.
Helical-threaded shank with at least one pitch
The shank including a curved lateral surface having at least one helical thread extending from a proximal end of the shank towards a distal end of the shank, the at least one helical thread including at least one pitch.
Across the independent claim, the coverage focuses on the combination of a colinear, instrument-driven head-neck-shank screw; a reverse frustoconical head shape with a helical thread that contacts bone to enhance purchase; and a curved shank surface with helical threads including at least one pitch. Dependent claims further constrain dimensions and define compression-neutral versus compression behavior using pitch relationships, and they add thread flutes such as cutting or reverse cutting flutes on the head thread.
Stated Advantages
Enhance the purchase of the head into the bone.
Documented Applications
Stabilizing fractures and osteotomies across hand/foot/long bones and the wrist, including bunion repair (as described in the provided partial content summary).
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