WO2018200127A1 - Implants d'arthroplastie et méthodes d'orientation de prothèses articulaires - Google Patents

Implants d'arthroplastie et méthodes d'orientation de prothèses articulaires Download PDF

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Publication number
WO2018200127A1
WO2018200127A1 PCT/US2018/025486 US2018025486W WO2018200127A1 WO 2018200127 A1 WO2018200127 A1 WO 2018200127A1 US 2018025486 W US2018025486 W US 2018025486W WO 2018200127 A1 WO2018200127 A1 WO 2018200127A1
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WIPO (PCT)
Prior art keywords
component
prosthesis
humeral head
coupler
bone
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Application number
PCT/US2018/025486
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English (en)
Inventor
C. Scott Humphrey
Original Assignee
Deltoid, Llc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Deltoid, Llc filed Critical Deltoid, Llc
Priority to AU2018256816A priority Critical patent/AU2018256816A1/en
Priority to JP2020509420A priority patent/JP2020518418A/ja
Priority to EP18790699.5A priority patent/EP3614973A4/fr
Priority to CN201880035261.3A priority patent/CN110678152A/zh
Publication of WO2018200127A1 publication Critical patent/WO2018200127A1/fr

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2/40—Joints for shoulders
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2/40—Joints for shoulders
    • A61F2/4003—Replacing only the epiphyseal or metaphyseal parts of the humerus, i.e. endoprosthesis not comprising an entire humeral shaft
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2/40—Joints for shoulders
    • A61F2/4014—Humeral heads or necks; Connections of endoprosthetic heads or necks to endoprosthetic humeral shafts
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2/3094—Designing or manufacturing processes
    • A61F2/30942—Designing or manufacturing processes for designing or making customized prostheses, e.g. using templates, CT or NMR scans, finite-element analysis or CAD-CAM techniques
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2/40—Joints for shoulders
    • A61F2/4081—Glenoid components, e.g. cups
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2002/30001—Additional features of subject-matter classified in A61F2/28, A61F2/30 and subgroups thereof
    • A61F2002/30108—Shapes
    • A61F2002/30199—Three-dimensional shapes
    • A61F2002/30252—Three-dimensional shapes quadric-shaped
    • A61F2002/30253—Three-dimensional shapes quadric-shaped ellipsoidal or ovoid
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2002/30001—Additional features of subject-matter classified in A61F2/28, A61F2/30 and subgroups thereof
    • A61F2002/30316—The prosthesis having different structural features at different locations within the same prosthesis; Connections between prosthetic parts; Special structural features of bone or joint prostheses not otherwise provided for
    • A61F2002/30329—Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
    • A61F2002/30331—Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements made by longitudinally pushing a protrusion into a complementarily-shaped recess, e.g. held by friction fit
    • A61F2002/30332—Conically- or frustoconically-shaped protrusion and recess
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2002/30001—Additional features of subject-matter classified in A61F2/28, A61F2/30 and subgroups thereof
    • A61F2002/30316—The prosthesis having different structural features at different locations within the same prosthesis; Connections between prosthetic parts; Special structural features of bone or joint prostheses not otherwise provided for
    • A61F2002/30535—Special structural features of bone or joint prostheses not otherwise provided for
    • A61F2002/30604—Special structural features of bone or joint prostheses not otherwise provided for modular
    • A61F2002/30616—Sets comprising a plurality of prosthetic parts of different sizes or orientations
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2/30767—Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
    • A61F2002/30934—Special articulating surfaces
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2/40—Joints for shoulders
    • A61F2/4014—Humeral heads or necks; Connections of endoprosthetic heads or necks to endoprosthetic humeral shafts
    • A61F2002/4018—Heads or epiphyseal parts of humerus
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2/40—Joints for shoulders
    • A61F2/4014—Humeral heads or necks; Connections of endoprosthetic heads or necks to endoprosthetic humeral shafts
    • A61F2002/4018—Heads or epiphyseal parts of humerus
    • A61F2002/4022—Heads or epiphyseal parts of humerus having a concave shape, e.g. hemispherical cups
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2/40—Joints for shoulders
    • A61F2/4014—Humeral heads or necks; Connections of endoprosthetic heads or necks to endoprosthetic humeral shafts
    • A61F2002/4051—Connections of heads directly to shafts

Definitions

  • the disclosure relates to the field of joint replacement, and more particularly total shoulder arthroplasty using prosthetic components.
  • the anatomic approach involves restoration of the humeral head to its pre-diseased state, with utilization of spherical humeral head components with proportional diameter and thickness.
  • the non-anatomic approach involves humeral head replacement with soft- tissue balancing of the rotator cuff utilizing spherical humeral head components of varying thicknesses.
  • reverse shoulder arthroplasty is considered non-anatomic shoulder replacement because the native glenoid side of the shoulder is converted to a sphere to mimic the humerus (glenosphere), while the humeral side is converted to mimic a glenoid (typically through replacement of the humeral head with a cup shaped implant).
  • Desired features of anatomic implants include replication of humeral neck angle, version, and posterior and medial offset.
  • stemmed arthroplasty systems are the most prevalent, and essentially all stemmed arthroplasty systems use spherical humeral heads.
  • the conventional belief is that roughly one-third of a sphere is considered to be the most anatomically correct shape of the current offerings. Regardless of head size, the ratio of the head height to the radius of curvature is about 3:4.
  • Clinical outcomes in patients who have received anatomically correct prostheses are generally regarded as superior when compared to soft-tissue balancing techniques using non-anatomically shaped (i.e., anatomically incorrect) prostheses.
  • a challenge in the art is the absence of anatomically correct head articulation surfaces. It is known that the native anatomical shape of the humeral head is not spherical, but elliptical (i.e., where the cross section of the humeral head has a radius of curvature in the superior to inferior dimension that is greater than the radius of curvature of the cross section in the anterior to posterior dimension). Recent research has shown that a prosthetic humeral head having a cross sectional shape adjacent to the bone cut that is elliptically-shaped and a generally spherical center point would theoretically allow a patient to have improved shoulder range of motion and function postoperatively.
  • a shoulder arthroplasty system would provide a wide range of head choices and offsets to most precisely match the patient's native anatomy. With such a system, a near perfect match could be achieved in a hemi-arthroplasty, and if the system were modular, could be adapted in a revision to provide an ideal match if the shoulder is converted to either a total arthroplasty or to a reverse shoulder arthroplasty.
  • elliptical humeral head implants are provided, and systems, assemblies, and methods comprising the same.
  • a system for long bone arthroplasty includes prosthesis components characterized as having a convex articulation surface that is hemielliptical and is defined by a major axis (corresponding to a frontal plane) and a minor axis (corresponding to a sagittal plane), a major diameter (DF) along the major axis and a minor diameter (DS) along the minor axis, and radii of curvature along the major axis (ROCF) and along the minor axis (ROCS), each prosthesis component comprising an apex and a base each having an elliptical cross sectional shape.
  • the system includes an array of humeral head prosthesis components, each humeral head prosthesis component in the array having a convex articulation surface that is hemielliptical and is defined by a major axis (corresponding to a frontal plane) and a minor axis (corresponding to a sagittal plane), a major diameter (DF) along the major axis and a minor diameter (DS) along the minor axis, and radii of curvature along the major axis (ROCF) and along the minor axis (ROCS), each prosthesis component comprising an apex and a base each having an elliptical cross sectional shape.
  • each prosthesis component comprising an apex and a base each having an elliptical cross sectional shape.
  • the array includes a plurality of prosthesis components that (i) vary from one another in their major diameters in a range from about 1 to 4 mm, and (ii) vary from one another in at least one of minor diameter, humeral head height (HHH), ROCF and ROCS as a function of DF.
  • the plurality of humeral head prosthesis components that vary from one another are characterized as varying from having a base with a more circular cross-sectional shape to a more elongated elliptical cross-sectional shape with increasing DF.
  • DF varies across the plurality of humeral head prostheses in the range from about 40mm to about 56mm. In accordance with some embodiments, DF varies across the plurality of humeral head prostheses in the range from at least 40mm to no more than 56mm.
  • the array of elliptical humeral head prosthesis components provides for anatomical fit relative to a native humeral head within a variation of up to and not more than 3 mm in one or both of the DF and DS dimensions in at least 96% and up to 99% of a patient population in which a native humeral head has a minor diameter that is equal to 0.69 times a major diameter plus an additional length in millimeters of 10.8 millimeters plus or minus 1 or 2 millimeters.
  • the plurality of humeral head prosthesis components is selected from the group of (i) an array of 5 heads that vary from one another in the major diameter in 4 mm increments, (ii) an array of 6 heads that vary from one another in the major diameter in 3 mm increments, (iii) an array of 9 heads that vary from one another in the major diameter in 2 mm increments, and (iv) an array of an array of 17 heads that vary from one another in the major diameter in 1 mm increments.
  • the system also includes at least one generally disc shaped coupler component having a central axis, and a prosthesis component side that includes a recess configured to interface with and engage the humeral head prosthesis component.
  • the recess has in some embodiments a substantially planar floor and a sidewall and at least one prosthesis component engagement feature.
  • the coupler also includes an opposing side having a bone contact surface, and a lateral edge that bounds the prosthesis component and opposing sides.
  • an anatomical fit of a humeral head prosthesis component selected from the array is achieved by selecting a head based on size and by rotationally varying orientation of the selected head as compared with a native humeral head to most closely match a native anatomy of the native humeral head.
  • an orientation of the major and minor axes of the humeral head prosthesis component relative to a center axis of the long bone is determined at the coupler-prosthesis interface.
  • the prosthesis component side of the coupler component is configured to interchangeably interface with and engage both a convex humeral head prosthesis component and a concave prosthesis component.
  • the system further includes a non-elliptical prosthesis component selected from one or more of (i) at least one concave cup having a cross sectional shape that is circular, and (ii) a convex head having a cross sectional shape that is circular.
  • the coupler component includes on the opposing side one or more of (i) a male taper, (ii) an anchor that is unitary with the coupler component and selected from a cage and a stem, and (iii) an anchor engagement feature extending from a surface and radially offset from the central axis.
  • the coupler component includes on its opposing side at least one anchor engagement feature extending from a surface and radially offset from the central axis.
  • the system also includes an anchor component that includes a proximal portion having a proximal surface for contacting at least a portion of the opposing side of the coupler component and a distal portion for positioning within a bone, the proximal portion of the anchor including on its proximal surface a coupler component engagement feature.
  • an arthroplasty assembly includes a prosthesis component and a coupler component engageable to provide an arthroplasty assembly, wherein the position of the prosthesis component can be varied rotationally around a shared central engagement axis with the coupler component.
  • the prosthesis component is selected from an array that includes a plurality of humeral head prosthesis components that (i) vary from one another in their major diameters in a range from about 1 to 4 mm, and (ii) vary from one another in at least one of minor diameter, humeral head height (HHH), ROCF and ROCS as a function of DF.
  • Each humeral head prosthesis component in the array has a convex articulation surface that is hemielliptical and is defined by a major axis (corresponding to a frontal plane) and a minor axis (corresponding to a sagittal plane), a major diameter (DF) along the major axis and a minor diameter (DS) along the minor axis, and radii of curvature along the major axis (ROCF) and along the minor axis (ROCS).
  • each prosthesis component has an apex and a base each having an elliptical cross sectional shape.
  • the coupler component includes a prosthesis component engagement side and an opposite side having a bone contact surface, and the sides are bounded by a lateral edge that is one of cylindrical, frustoconical and frustohemispherical. According to such embodiments, when one of the selected prosthesis and coupler components are engaged and the coupler component is recessed into bone, rotation of the prosthesis component within the coupler component provides alignment of the bone articulation surface of the prosthesis component with the bone that is anatomically similar to a native long bone.
  • the assembly is anchorless.
  • the assembly includes an anchor component
  • the coupler component is selected from an array that includes of a plurality of coupler components, each of which includes on its opposing side a variably positioned anchor engagement feature.
  • each of at least two of the plurality of coupler components has at least one anchor engagement feature that is off-center from a center point of the coupler component, the off- center engagement feature on each of the at least two coupler components at a different distance in at least one dimension relative to the center point.
  • the anchor component is selected from an array that includes a plurality of anchor components each having a proximal portion with a proximal surface for contacting at least a portion of the coupler component and a distal portion for positioning within bone.
  • the proximal portion has an angle of inclination relative to the long bone into which it is to be implanted of from about 120 to about 145 degrees, and also includes a coupler component engagement feature.
  • a method for implanting a modular system for long bone arthroplasty includes use of an arthroplasty assembly according to one of the foregoing embodiments.
  • the method further includes selecting coupler and prosthesis components, at least provisionally fitting the selected coupler component into a metaphysis of a long bone; and engaging the selected prosthesis component into the recess of the prosthesis component side of the coupler component.
  • the assembly is anchorless.
  • the coupler component includes on the opposing side, one or more of a male taper, an anchor that is unitary with the coupler component and selected from a cage and a stem, and an anchor engagement feature extending from a surface and radially offset from the central axis.
  • the method includes use of a coupler component that has at least one anchor engagement feature extending from the bone contact surface and radially offset from the central axis, and an anchor component that has a proximal portion with a proximal surface for contacting at least a portion of the anchor component side of the coupler component and a distal portion for positioning within a bone.
  • the proximal portion includes on its proximal surface a coupler component engagement feature, wherein an orientation of the major and minor axes of the humeral head prosthesis component relative to a center axis of the long bone is determined at the coupler- prosthesis interface, and wherein an offset of the prosthesis component from the center axis of the long bone is determined at the anchor-coupler interface.
  • FIG 1 is a diagram showing the transverse, frontal and sagittal planes in the context of human anatomy
  • FIG 2 shows a hemi view of a humeral head prosthesis and alternate frontal and side views of a bone cut line on a humerus, indicating the diameter and radius of curvature of each of the frontal and sagittal planes;
  • FIG 3 shows in upper and lower panels alternate front, side and back views of a humerus, indicating key landmarks for determining diameter and radii of curvature to describe the humeral head prosthesis, wherein the lower panel provides stepwise images indicating the steps for characterizing the humeral head prosthesis features as described in the Examples;
  • FIG 4 shows alternate views of a cut humerus indicating the radius of curvature in the frontal plane (SI);
  • FIG 5 shows alternate views of a cut humerus indicating the radius of curvature in the sagittal plane (AP);
  • FIG 6 is a diagram showing variation of the diameter in the frontal plane as humeral size increases;
  • FIG 7 shows side and perspective views of a spherical humeral head prosthesis and a elliptical humeral head prosthesis indicating the frontal and sagittal diameters and radii of curvature;
  • FIG 8 shows front and back perspective views of anchored and anchorless embodiments of a modular arthroplasty assembly including a spherical head articulation surface (left two images, top and bottom) and a concave cup articulation surface (right two images, top and bottom) assembled in the context of a humerus;
  • FIG 9 shows side views of stemless embodiments (with a cage) of a modular arthroplasty assembly including a spherical head articulation surface (left image) and a concave cup articulation surface (right image) assembled in the context of a humerus;
  • FIG 10 shows an exploded side view of an embodiment of a modular arthroplasty assembly with a stem, showing alternate stem lengths and alternate embodiments of an articulation surface ("prosthetic component") in the form of a spherical head and a concave poly cup;
  • prosthetic component an articulation surface
  • FIG 11 shows from top left to bottom right, alternate top perspective and cross- sectional top perspective, side and top views of an embodiment of a coupler/metaphyseal shell
  • FIG 12 shows in the top row alternate side and cross-sectional perspective views of an embodiment of a coupler/metaphyseal shell that lacks an anchor, and in each of the middle and bottom rows, top, bottom and top perspective views of a coupler/metaphyseal shell having one or two teeth and recess engagement features on the interior sidewall;
  • FIG 13 shows in the top row a side view and a cross sectional side view of an embodiment of a coupler/metaphyseal shell having a frustohemispherical shape as shown in the center row of FIG 12, and in the bottom row a side view and a cross sectional side view of an embodiment of a coupler/metaphyseal shell having a frustohemispherical shape as shown in the bottom row of FIG 12;
  • FIG 14 shows an array of sizes of a representative embodiment of a coupler/metaphyseal shell shown from the side, the top and the bottom;
  • FIG 15 shows alternate side, front and front cross-sectional views of a representative embodiment of a diaphyseal stem
  • FIG 16 shows a table designated TABLE I that provides parameter measurements for prosthetic humeral head sets A-D;
  • FIG 17 shows a table designated TABLE II that provides results based on head type and number of heads per set;
  • FIG 18 shows a table designated TABLE III that provides results with arrays of heads analyzed by dimensional parameter
  • FIG 19 shows alternate views of the articulation of a spherical vs. an elliptical humeral head prosthesis relative to a glenoid;
  • FIG 20 shows scatter plots with linear trend lines demonstrating in the upper panel graphic the formulae from the anatomical stud and in the lower panel graphic the mathematical relationship between the length difference between the head axes in the frontal and sagittal planes (DF - DS) and the diameter of the base of the head in the frontal plane (DF);
  • FIG 21 shows scatter plots with linear trend lines demonstrating in the upper panel graphic the formulae from the anatomical study versus spherical heads, and in the lower panel graphic the formulae from the anatomical study versus heads with a fixed 4 mm difference (DF - DS);
  • FIG 22 shows scatter plots with linear trend lines demonstrating in the upper panel graphic the mathematical relationship between the humeral head prosthesis height (HHH) and the diameter of the base of the head in the frontal plane (DF), and in the middle panel graphic the mathematical relationship of the radius of curvature in the sagittal plane (ROCS) vs. DF, and in the lower panel graphic the mathematical relationship of the radius of curvature in the frontal plane (ROCF) vs. DF; and
  • FIG 23 is a graphic of a step in the sequence of a representative embodiment of a surgical technique for implanting an arthroplasty system in accordance with the disclosure showing a perspective view of a bone cut on a humerus with steps for preparation of the bone to receive a coupler/metaphyseal shell, and steps for selection of the position in the bone of an stemmed anchor, including a stem trial and representative shell offset selection tool for positioning an offset of a prosthesis component relative to the bone.
  • the major diameter is the diameter at the base of the humeral head in the frontal plane (DF - from S to I) and the minor diameter is the diameter in the sagittal plane (DS - from A to P).
  • Each humeral head prosthesis component in the array has a major diameter and a minor diameter that are not equal, and each of these features is also different from each of the other humeral head prosthesis components in the array.
  • the ratio of the minor diameter to the major diameter decreases, whereby from smaller to larger, the humeral head prosthesis components vary from having a base with a more circular cross sectional shape to a more elongated elliptical cross sectional shape with increasing size.
  • Much emphasis has been placed on replicating normal, prepathologic anatomy during shoulder reconstructive surgery. Use of a prosthetic humeral head that is inaccurately sized or positioned may lead to poor clinical outcomes, including shoulder stiffness and rotator cuff tearing. It has been reported that alterations to humeral head geometry may produce eccentric loading at a prosthetic glenoid that may contribute to early component wear and loosening.
  • a goal in shoulder arthroplasty is to replicate as closely as possible the size and position of the articular surface at the base of the humeral head so that it is within 3 mm of the normal anatomy.
  • FIG 7 depicts relationships of features of spherical and. elliptical heads.
  • the elliptical shape of the humeral head has been vaguely described and as mentioned herein above, and others have described the average difference between the DF and DS measurements at the humeral head base from about 2 mm, to about 3.9 on average.
  • the inventors are the first to show that the elliptical shape of the base of the humeral head seems to elongate in the frontal plane as head size increases, and thus, the relationship between DF and DS is not a constant.
  • elliptical humeral head prostheses having an elliptical articulation surface are provided in arrays, including, a set comprising as few as five (5) elliptical heads can match about 96% of a patient population, and about six (6) elliptical heads can match about 99% of a patient population.
  • One or more of the heads in an array is selected for combination with at least a coupler (convertible offset coupler/metaphyseal shell) and in some embodiments an anchor.
  • the inventors provide here in some embodiments is a novel system of humeral head prostheses having anatomically relevant shapes that overcome the shortcomings in the existing art with respect to anatomically relevant shape that can positively influence clinical outcomes for arthroplasty patients.
  • These novel humeral heads have the feature of being hemi elliptical, with elliptical apexes and with elliptical bases (essentially at a base that would correspond with the bone cut made at the base of an anatomical head of a humerus).
  • prosthesis components for long bone arthroplasty including an array of elliptical heads comprising from 5 to 17 elliptical heads is provided, wherein each head in the array of heads varies from the others in the diameters at the base of the head in both the frontal (DF) and sagittal (DS) planes, the radii of curvature in both the frontal (ROCF) and sagittal (ROCS) planes, and humeral head height (HHH).
  • the prosthetic heads of each head type vary in size within the array from small to large in 4, 3, 2, or 1 mm increments, wherein the values for the smallest to the largest heads is expressed as DF > 40mm, and DF ⁇ 56 mm, respectively.
  • the number of heads per array can vary from 5, 6, 9 and 17, based on the dimensional value by which the head size is incrementally increased: starting at 40mm, wherein a 4mm incremental increase in head size based on an increase of DF provides a set with 5 heads (Set A), a 3mm incremental increase in head size based on an increase of DF provides a set with 6 heads (Set B), a 2mm increase in head size based on an increase of DF provides a set with 9 heads (Set C), and a 1mm increase in head size based on an increase of DF provides a set with 17 heads (Set D).
  • a 4mm incremental increase in head size based on an increase of DF provides a set with 5 heads (Set A)
  • a 3mm incremental increase in head size based on an increase of DF provides a set with 6 heads (Set B)
  • a 2mm increase in head size based on an increase of DF provides a set with 9 heads (Set C)
  • the arrays are adapted to cover the range of humeral head sizes based on anthropometric data to provide for suitable and sufficient anatomical fit within a variation of up to and not more than 3 mm in at least 96% of a patient population, and up to 99% of a patient population.
  • the anatomical fit is achieved by selecting a head from the array based on size and by varying the orientation of the selected head positioned in the bone to most closely match the native anatomy of a humeral head diameters of the base of the head in both the frontal (DF) and the sagittal (DS) planes, and the radii of curvature in both the frontal (ROCF) and sagittal (ROCS) plane.
  • each of the other humeral head prosthesis components in the array is characterized by having a minor diameter (in millimeters) that is equal to 0.69 times the major diameter (in millimeters) plus an additional length in millimeters of 10.8 millimeters, plus or minus 3 millimeters.
  • each humeral head prosthesis component in the array is characterized by having a minor diameter (in millimeters) that is equal to 0.69 times the major diameter (in millimeters) plus an additional length in millimeters that ranges from 6.80 millimeters to 14.80 millimeters.
  • each humeral head prosthesis component in the array may be characterized by the minor diameter having a length that is equal to (0.69 times the major diameter) plus 10.8 mm. And in other embodiments, each humeral head prosthesis component in the array may be characterized by the humeral head prosthesis having a height that is equal to (0.30 times the major diameter) plus 3.2 mm plus or minus 3 mm.
  • each humeral head prosthesis component in the array may be characterized by the humeral head prosthesis having along the major axis a radius of curvature that is equal to (0.53 times the major diameter) minus 0.5 mm plus or minus 2 mm.
  • each humeral head prosthesis component in the array may be characterized by the humeral head prosthesis having along the minor axis a radius of curvature that is equal to (0.44 times the major diameter) plus 2.2 mm plus or minus 2 mm.
  • each humeral head prosthesis component in the array may be characterized by the features of a minor diameter that ranges from about 36 to 51 mm, a major diameter that ranges from about 37 to about 56 mm. And in further specific embodiments, each humeral head prosthesis component in the array may be characterized by a ratio of the minor diameter to the major diameter ranges from 0.87 to 1. And in still other embodiments, each prosthesis component in the array may be characterized by an angle of inclination ranges from 120 degrees to 143 degrees. And in still other embodiments, each prosthesis component in the array may be characterized by and a height of the humeral head prosthesis ranges from about 12 to 25 mm.
  • one or more than one of the above described features may characterize humeral head prosthesis components within the disclosure.
  • one or more unique arrays may be provided wherein the two or more prosthesis components in the array include one or any combination of the above described features, such arrays suited to one or more of specific patient populations that represent smaller or larger overall body types, or ethnic or geographical origins.
  • the examples provided herein with respect to the reported data, and the representative examples of humeral head prostheses and arrays are not limiting and are merely representative of the possible arrays which can be provided based on the disclosure.
  • a humeral head prosthesis is provided that is characterized by one or more of the features selected from the group including:
  • DMaj-DMin a difference between the major and minor diameters (DMaj-DMin) and the ratio of the minor to major diameters (DMin/DMaj), wherein DMaj-DMin ranges from about 1 to about 15 mm, and wherein DMin/DMaj ranges from about 1 to about 0.8;
  • the humeral head prosthesis component is characterized by having a minor diameter (in millimeters) that is equal to 0.69 times the major diameter (in millimeters) plus an additional length in millimeters that ranges from 7.80 millimeters to 13.80 millimeters.
  • the humeral head prosthesis is characterized by one or more of the features selected from a minor diameter that ranges from about 36 to 51 mm, a major diameter that ranges from about 37 to about 56 mm, a ratio of the minor diameter to the major diameter ranges from 0.87 to 1, an angle of inclination ranges from 120 degrees to 143 degrees, and a height of the humeral head prosthesis ranges from about 12 to 25 mm.
  • the various elliptical humeral head prostheses, and arrays of prostheses may be provided for use in conjunction with the modular systems and assemblies as described herein or may be adapted for use with other modular assemblies.
  • the hemielliptical humeral heads as described herein may be adapted for use in monolithic designs that include an attached anchor rather than engageable with a modular anchor.
  • the examples and representative embodiments are not limiting with respect to the use of the novel elliptical humeral head generally characterized by a ratio relationship of the minor diameter divided by the major diameter of the base, the array comprising a plurality of humeral head prosthesis components, each having a major diameter and a minor diameter that is different from each of the other humeral head prosthesis components in the array, wherein as the major diameter is increased the ratio of the minor diameter to the major diameter is decreased, whereby the humeral head prosthesis components vary from having a base with a more circular cross sectional shape to a more elongated elliptical cross sectional shape with increasing size.
  • a modular system for long bone arthroplasty provides the elliptical headed prosthesis arrays, and one or more of coupler components (also referred to as metaphyseal shell) and optional anchor components that are engageable to provide an arthroplasty assembly wherein the position of the prosthesis component can be varied rotationally around a shared central engagement axis with the coupler component.
  • coupler components also referred to as metaphyseal shell
  • anchor components that are engageable to provide an arthroplasty assembly wherein the position of the prosthesis component can be varied rotationally around a shared central engagement axis with the coupler component.
  • the position of the anchor component relative to the coupler component can be varied in two dimensions on a plane that is perpendicular to the central engagement axis of the coupler and prosthesis components by selecting the coupler component from an array comprising a plurality of coupler components that include variably positioned anchor engagement features.
  • each of at least two of the plurality of coupler components comprises at least one anchor engagement feature that is off-center from a center point of the coupler component, and the off- center engagement feature on each of the at least two coupler components is at a different distance in at least one dimension that is perpendicular to the central engagement axis.
  • the assembly achieves alignment of the bone articulation surface of the prosthesis component with the bone that is anatomically similar to a native long bone.
  • the position of an elliptical head may be rotated at its engagement with the anchor to achieve the desired orientation relative to the bone.
  • the prosthesis component is adapted for engagement with one or the other of the coupler component or an anchor.
  • the head and the coupler are each adapted, respectively, with a male insert and a female receiver channel (such as a Morse type taper) for engagement there between.
  • the dimensions of the engagement features may vary in length and diameter, and in general, the dimensions of these features can range from 5 mm to more than 100 mm.
  • shells may be provided with engagement means, such as a taper, in heights and in greater and lesser diameters ranging in mm increments and fractions thereof from 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83,
  • FIG. 12 and FIG 13 each of which drawings show side views of representative embodiments prosthesis components with engagement means in the form of concentric teeth positioned at the base of a taper on each of the alternate cup shaped implants.
  • the tabs or teeth may be notched to engage with corresponding splines or ribs to enable alignment and prevent axial displacement.
  • Other means known in the art may be employed for engagement between the metaphyseal shell and prosthesis.
  • the dimensions of the engagement features including the representative tab features shown in the drawings, may vary in height and depth and spacing, and in general, the dimensions of these features can range from 0.1 mm to more than 20 mm.
  • shells may be provided with the depicted engagement means, in mm increments and fractions thereof from 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20 mm.
  • FIG 12 and FIG 13 each show alternate views of metaphyseal shells adapted with different engagement means which in the depicted embodiments are positioned at the base of the recess in the shells adjacent to the interior sidewalls thereof.
  • the various engagement means are not intended to be limiting, and other engagement means that are not shown may be used, moreover, the engagement means may be used in the context of any form of prosthetic component and may be used interchangeably between them.
  • the shells include on their prosthesis surfaces other features that aid in placement and in removal.
  • one or more slots or other access portals may be provided on a shell or plug component to enable passage of an osteotome or other device to facilitate freeing an implant from bone due to boney ingrowth thereupon.
  • one or more circumferential tool engagement features such as are shown on the upper periphery of the interior wall of the metaphyseal shell embodiments shown in FIG 11, FIG 13 and FIG 14, may be provided to aid in the placement and press-fit fixation of the shell into bone, and subsequent adjustment or removal thereof in the event of a revision surgery.
  • the cup and the coupler are each adapted with an engagement means.
  • the engagement means comprises a snap fit tooth engagement feature.
  • the coupler includes engagement features that allow engagement and fixation with each of the head and cup prostheses.
  • a coupler is adapted with one or the other of head and cup prosthesis engagement features.
  • the disclosed system enables achievement of a more anatomically accurate joint replacement aimed at reducing clinically adverse consequences.
  • the coupler with its eccentric taper enables a wider range of selection of head/cup orientation without compromise of height, neck angle, version, and posterior and medial offset.
  • This offset function together with the anatomical benefits thereby attained, finally solves a vexing challenge in the art. That is, provision for truly adaptable and convertible, anatomically accurate implants - a challenge that has been heretofore addressed, inadequately at best, with either expansive prosthetic head inventory and/or adjustable systems that sacrifice one or more of the anatomically desirable implant features such as component height, neck angle, version, and posterior and medial offset.
  • This disclosure describes various exemplary convertible implant components and systems, convertible shoulder prosthesis systems, and methods for implantation of these. While the description below sets forth details of features of the modular arthroplasty assembly, one of skill will appreciate that the features may also be shared by other system components, such as those that are used to determine implant size and positioning, generally referred to as trials. Moreover, the features and elements as described herein for the shoulder and humerus may be readily adapted for use in the context of other long bones.
  • novel elliptical humeral head prostheses and systems for long bone arthroplasty are provided.
  • the system comprises an array of novel elliptical humeral head prosthesis components where each prosthesis component in the array has a convex articulation surface that is hemielliptical.
  • This hemielliptical surface is defined by a major axis, a minor axis, an apex, and a base having an elliptical cross sectional shape defined by a major diameter along the major axis and a minor diameter along the minor axis.
  • each prosthesis component is characterized by a ratio relationship of the minor diameter divided by the major diameter of the base.
  • FIG 1 shows frontal, sagittal and horizontal (transverse) planes relative to a human body and establishes the planes in relation to features of the arthroplasty components as described herein.
  • the novel arrays of humeral heads herein are characterized by having a diameter in the major axis (DF - corresponding to the frontal plane which transects the joint from superior to inferior) and a diameter in the minor axis (DS - corresponding to the sagittal plane which transects the joint from anterior to posterior), where the difference between the diameter on the major axis minus the minor axis (DF - DS) varies as the measurement DF increases.
  • the inventors have described formulae for the novel humeral head array. And as further provided herein and set forth in the claims, the inventors have described other features of relationships between DF and DS, and the radii of curvature.
  • humeral head prostheses and arrays wherein a prosthesis selected from the array based on a patient's DF measurement would have a 97% likelihood of having a 3 mm or less deviation from the size and position of the articular surface at the base of the prosthetic humeral head relative to the patient's normal anatomy.
  • the upper portion shows alternate views of a humerus shown at the bone cut after removal of the anatomical humeral head.
  • the critical point (CP) and the distal articular mid-point (DAM) are identified before the virtual humeral head resection while determining the humeral head equator as described in the literature by Hertel.
  • the length of the diameter of the base of the humeral head in the frontal plane (DF) can be measured as the shortest distance between CP and DAM.
  • DS (the length of the diameter of the base of the humeral head in the sagittal plane) bisects and is perpendicular to DF.DF.DS, and the distance between the bicipital sulcus and critical point (S/E) were identified and measured directly on 3D computer models of humerii.
  • FIG 2 in the lower portion is an image of an elliptically shaped prosthetic humeral head shown together with formulae that describe the features and relationships there between of a natural humeral head.
  • the formulae for any given value of the diameter of the humeral head in the frontal plane (DF - from superior to inferior - dashed black line), the inventors surprisingly discovered through a study of a large number of humeral heads that one may calculate the values of the other humeral head dimensions, including the diameter of the humeral head in the sagittal plane (DS - from anterior to posterior— dashed white line), humeral head height (HHH— dashed gray line), radius of curvature in the frontal plane (ROC F — black arc), and radius of curvature in the sagittal plane (ROCS— white arc).
  • FIG 3 provides additional details relative to the anatomically relevant markers that were identified in the sample of humerii for providing the parameters and formulae as described herein for elliptical non-spherical humeral head prostheses.
  • FIG 3 shows anthropometric measurements: AX, long axis of the humerus; CD, critical distance; CP, critical point; COR, center of rotation; DAM, distal articular midpoint; DF, diameter of the base of the humeral head in the frontal plane; DS, diameter of the base of the humeral head in the sagittal plane; HHH, humeral head height; IA, inclination angle; MO, medial offset; PO, posterior offset; SA, surface arc. [085] Referring now to FIG 4 and FIG 5, marked simulated radiographs for anthropometric measurement with reference to the anatomical features as shown in the illustrations.
  • the images were produced, whereby (A) To obtain the ideal view for the simulated anterior-posterior radiographs, the humeral head model is oriented so that DF is parallel to while DS is perpendicular to the computer screen. (B) A custom-made ruler with a center slot is used to mark the long axis of the humerus in the frontal plane. (C) Custom-made circular templates that increase in size in 1-mm increments are used to identify the center of rotation and to size the radius of curvature in the frontal plane. (D) Additional lines are added as shown. (E) To obtain the ideal view for the simulated medial-lateral radiographs, the humeral head model is oriented so that DS is parallel to while DF is perpendicular to the computer screen.
  • a custom-made ruler with a center slot is used to mark the long axis of the humerus in the sagittal plane.
  • G Custom-made circular templates that increase in size in 1-mm increments are used to identify the center of rotation and to size the radius of curvature in the sagittal plane.
  • H Final markup for the simulated medial-lateral radiographs.
  • SI frontal
  • AP sagittal planes
  • the relative difference between the DF and DS may be typically about 2 mm and up to 4 mm in the context of elliptical humeral heads, which has been treated in the art as a constant variation even as head size increases. What has not been known or suggested in the art heretofore is that this difference between DF and DS is not a constant but varies as head size increases. Accordingly, prosthetic humeral heads that have been designed based upon what has been known have been defective in the relationship between DF and DS relative to native anatomy in at least some populations.
  • FIG 2 and FIG 6 - FIG 7 provide details and formulae for the relationships of the features of DF, DS, and HHH and the radii of curvature in the frontal and sagittal planes as size increases overall. Further details are shown in FIG 16 - FIG 22, which show data and various scatter plots with linear trend lines demonstrating the mathematical relationship between the length difference between the humeral head axes in the frontal and sagittal planes (DF - DS) and the diameter of the base of the humeral head in the frontal plane (DF), and other features of native humeral head anatomy, which data are further illuminated in the Examples.
  • the shape of the humeral head prosthesis is generally elliptical (i.e. non-spherical), allowing an enhanced selection to achieve anatomical matching between the removed native humeral head and the prosthesis.
  • use of humeral heads that have a non-circular elliptical cross section are particularly desirable for providing the widest array of options to replicate native anatomy and to avoid functional problems for the patient with the arthroplasty.
  • humeral heads that have a non-circular elliptical cross section, and in some embodiments used together with a novel coupler component, enables the surgeon to accommodate one or more of offsets in positioning from the sagittal/ AP and frontal/SI planes, but also rotational positioning of the humeral heads that have a non- circular elliptical cross section to achieve the most desirable replacement anatomy.
  • humeral head prostheses and arrays thereof have dimensions that are suited to allow a range of custom fits to best match a subject's anatomy.
  • humeral heads vary in terms of shape (from more round to elliptical), height (distance from the engagement surface to the apex), and peripheral dimension (circumference for round heads and DS to DF dimensions for elliptical heads).
  • the overall shape of the humeral heads at the apex is generally spherical, though the scope of the invention includes use of humeral heads that may have another shape that is not spherical.
  • humeral heads having spherical apexes would present a glenoid articulation surface that is spherical and would taper along the DF dimensions to the periphery along a generally elliptical arc (ROCF). And in some further embodiments, the head would taper along the DS dimension along a generally elliptical arc (ROCS).
  • FIG 20 - 22 various aspects of the relationships of anatomical humeral heads are shown which inform the described humeral head prostheses and arrays hereof.
  • the graphic in the upper panel of reveals that for smaller head sizes (DF ⁇ 45 mm), the difference between DF and DS measurements is always less than or equal to about 4 mm, but once DF increases to beyond 52 mm., the difference is always >4 mm.
  • the effect of the mismatch seen with use of a spherical prosthetic head is more likely to be of consequence in patients with larger humeral heads because the patient's size variation is not accounted for by the prosthesis shape, thus the size and position of the articular surface at the base of the prosthetic head will be well outside of the goal of achieving a 3 mm or less deviation from normal anatomy.
  • the graphic in the lower panel of FIG 20 compares the formula from the inventors' anatomical study, reported below, versus spherical heads, versus heads with a fixed 4 mm DF and DS difference (DF-DS).
  • the shaded grey area is the data plot from the population study +/-3 mm.
  • the shortcomings of the spherical head design are obvious.
  • the spherical size remains within this +/-3 mm goal range only for the smallest, individuals; if the DS measurement were used in sizing a spherically shaped humeral head during arthroplasty surgery, the mismatch in the DF direction would be at most 4 mm for a smaller patient; but in larger patients, the mismatch would, be 4 mm at a minimum, and it could be >9 mm in some patients.
  • humeral head prosthesis designs currently known in the art present less than ideal matching to native patient anatomy, both in the case of spherical humeral heads and elliptical humeral heads having constant DF-DS offsets of about 2 mm to about 4 mm.
  • humeral head prostheses and arrays of humeral head prosthesis components are provided, wherein each prosthesis component in the array has a convex articulation surface that is hemi-elliptical and defined by a major axis, a minor axis, an apex, and a base having an elliptical cross sectional shape defined by a major diameter along the major axis and a minor diameter along the minor axis.
  • Each prosthesis component in the array is characterized by a ratio relationship of the minor diameter divided by the major diameter of the base, each having a major diameter and a minor diameter that is different from each of the other prosthesis components in the array, wherein as the major diameter is increased the ratio of the minor diameter to the major diameter is decreased.
  • the humeral head prosthesis components in the array vary from having a base with a more circular cross sectional shape to a more elongated elliptical cross sectional shape with increasing size.
  • the DF and DS dimensions of a humeral head according to the disclosure are in reference to a cross sectional plane of a humerus essentially in the DS plane with an inclination angle off that plane from about 120 to 145 degrees, and in some embodiments from 120 to 143, and in certain disclosed embodiments herein, of about 135 degrees.
  • the cut corresponds to the anatomical neck of the humerus as depicted, for example, in FIG 3, and also see URL (//en.wikipedia.org/wiki/Anatomical_neck_of_humerus).
  • the humeral head prosthesis may be provided for implantation at an angle of inclination from and including angle increments in between 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, and 145.
  • stems and other arthroplasty components are provided for engagement with a humeral head prosthesis having an inclination that is about 135 degrees, or otherwise as provided herein.
  • the stems could be provided having a different angle of inclination, and that the ultimate angle of inclination of an implant is determined based on the angle selected by the surgeon when selecting the prosthesis components to provide an optimally anatomical match to the patient.
  • FIG 7 shows an exemplary elliptical head that has a size as described by its major and minor axes, dimensions and radii of curvature.
  • the heads vary in size relative to a bone cut on the DS plane.
  • arrays can be described as follows, where each prosthesis in the array have diameter dimensions that range from 30 mm to 62 mm in the superior to inferior dimension (DF), and range from 30 to 58 mm in the anterior to posterior dimension (DS).
  • the DF range is from 37 to 56 mm and the DS range is from 36 to 51 mm.
  • the DF range can encompass from 20 to 80 mm, and can include sizes in the DF dimension from and including the following and increments in between: 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80 mm.
  • the DS range can encompass from 20 to 80 mm, and can include sizes in the DS dimension from and including the following and increments in between: 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80 mm.
  • the arrays and the discrete prostheses will have elliptical head properties in accordance with one or more of the formulae and DS to DF relationships as described herein.
  • humeral head sizes that may encompass the following array, wherein the DS dimension ranges from 36 to 51 mm, the DF dimension ranges from 37-56 mm, the ratio of DS/DF ranges from 0.87 to 1, and wherein the angle of inclination ranges from 120 degrees to 143 degrees.
  • Specific humeral heads within the array are provided in sizes having humeral head heights ranging from 12 to 25 mm, and in representative embodiments from 14 to 21 mm, and in certain specific embodiments in increments there between.
  • the relationship between the DF to DS dimensions in one embodiment of elliptical heads is 1 (spherical heads).
  • the DF to DS dimensions are related in a range where the DF dimension is about 2 mm larger than the DS dimension regardless of head size.
  • the variation between the DF and DS dimensions may vary from 0.5 mm to 10 mm or more, and thus can include variation in mm and increments in between including 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 mm.
  • the DF to DS dimensions are related in a range where the DS/DF ratio changes from 1 to 0.85 as the head size and DF increases.
  • the range in variation between the DF and DS dimensions can include from 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, and 2 mm and incremental fractions there between.
  • the elliptical humeral heads may be used together with a coupler/metaphyseal shell that is engageable with a prosthesis component, for example an elliptical humeral head prosthesis component, according to the disclosures to provide an arthroplasty assembly.
  • FIG 8 - FIG 10 show alternate views of systems that comprise prostheses components and one or more of anchors and couplers in the context of bony anatomy.
  • FIG 10 shows optional components of an assembly for long bone arthroplasty, the assembly including one or more elliptical head prostheses, and one or more of coupler and anchor prostheses.
  • one or more alternate anchors selected from stems and cages may be included, and the assemblies may contain spherical heads and cup shaped prostheses (see for example FIG 11 and FIG 8), each of the various prostheses inter-engageable with a coupler component to maximize the options for a surgeon and to provide a system that is adaptable for revision without the need to remove the entire implant, particularly when a coupler component is used, with or without any anchor (examples with and without anchors shown in FIG 8).
  • FIG 8 shows alternate perspective views of various embodiments of a modular arthroplasty assembly with a coupler component.
  • FIG 15 depicts alternate views of an exemplary anchor that may be used, the anchor comprising an elongate stem and a contact surface comprising an engagement feature in the form of a female taper for engagement with one of a coupler component and a prostheses component.
  • the coupler when used with an anchor, enables variable positioning of the prosthesis component relative to the long axis of the bone, assembled in the context of a shoulder bone.
  • the position of the prosthesis component can be varied rotationally around a shared central engagement axis with the coupler component to allow for selection of the optimal anatomical positioning of the elliptical humeral head.
  • a position of the anchor component relative to the coupler component can be varied in two dimensions on a plane that is perpendicular to the central engagement axis of the coupler and prosthesis components by selecting the coupler component from an array comprising a plurality of coupler components that include variably positioned anchor engagement features.
  • a modular arthroplasty assembly includes the components of: (a) an elliptical head selected from an array as described above and (b) a convertible coupler bounded on a first side by an implant surface adapted to receive an implant component, and bounded on an opposite second side by a bone contact surface.
  • the assembly may also include one or more of an array of prosthesis components that are selected from one of a hemispherical humeral head and a cupped reverse prosthesis.
  • the assembly may include an anchor.
  • each of at least two of the plurality of coupler components comprises at least one anchor engagement feature that is off-center from a center point of the coupler component, and the off- center engagement feature on each of the at least two coupler components is at a different distance in at least one dimension that is perpendicular to the central engagement axis.
  • the assembly achieves alignment of the bone articulation surface of the prosthesis component with the bone that is anatomically similar to a native long bone.
  • a modular arthroplasty assembly includes (a) an convertible offset coupler bounded on a first side by an implant surface adapted to receive an implant component, and bounded on an opposite second side by a bone anchor engagement surface, (b) an elliptical non spherical humeral head prosthesis component, and optionally, (c) a bone anchor configured to be inserted in bone and adapted for engagement with the convertible offset coupler.
  • the concentric coupling feature on the humeral head prostheses provides a superior solution for use of elliptical heads to achieve an optimized anatomical match and is a key aspect of the novel system disclosed herein to allow anatomical matching for up to 97% of patients (based on the study data reported in the Examples herein).
  • Rotational orientation occurs at the humeral head prosthesis-coupler engagement interface, while offset occurs at the coupler/anchor engagement interface.
  • any surgical revision that may be necessitated can be more easily achieved than is currently possible in the art by use of the coupler, which allows positional adjustment, replacement, removal and replacement of the head with a cup to achieve a reverse arthroplasty, all without the need for complete removal of the shell/anchor implant from the humerus.
  • the overall shape of the coupler is generally cylindrical, with an outer surface and dimensions that are adapted for insertion at least partially within humeral bone and is bounded on a first side by an implant surface adapted to receive an implant component, and on an opposite second side by a bone anchor engagement surface.
  • the coupler is adapted with at least or one another of a male insert and a female receiver channel (such as a Morse type taper), on one or both opposing sides, and optionally adapted to receive one or more of a pin or setscrew or other fastener to achieve engagement with at least one of the prosthesis component and the bone anchor.
  • the coupler bears on a lateral peripheral edge a surface feature that is adapted to enhancing boney ingrowth. Accordingly, in some embodiments, all or a portion of the outer surface of the coupler may be adapted with surface texturing to encourage bone ingrowth or ongrowth. In addition, the stem engagement surface may be adapted with surface texturing to enhance engagement there between. In various embodiments, the coupler includes at least one engagement feature that allows engagement and fixation with each of the humeral head and cup prostheses.
  • a coupler with an offset for engagement with an anchor is selected from offsets ranging in mm and increments thereof from 0 to 20 mm, and includes 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20.
  • the range of offset may be from 0 to 10
  • the offset may be from 0 to 6 mm.
  • the exemplary set of couplers may be characterized as representing offsets of 0, 1, 2, and 3 mm.
  • the couplers may vary in diameter from about 30 to 45 mm, more particularly from 34 to 40 mm, and in some specific embodiments include sizes that are 34, 36, 38 and 40 mm in diameter, respectively. Of course other sizes and incremental portions thereof are possible, and can range from 5 mm to more than 100 mm in diameter depending on the subject.
  • couplers may be provided in heights ranging in mm increments and fractions thereof from 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 to 100, and in diameters in mm increments and fractions thereof from 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22,
  • a coupler is selected for its height, diameter, and engagement feature offset using tools for offset measurement as described further herein below.
  • the selected coupler is placed in the bone, its male taper engaged with the female taper of the stem; a set screw is inserted through the taper to engage the coupler with the stem to secure the implant system in preparation for engagement with the humeral head or cup prosthesis.
  • a modular system for long bone arthroplasty includes an elliptical humeral head prosthesis, an anchor component, the humeral head prosthesis component engageable with the anchor component to provide an arthroplasty assembly, wherein the position of the humeral head prosthesis component can be varied rotationally around a shared engagement axis with the anchor component.
  • this coupler is positioned by countersinking in bone, such as the cut humeral head bone in the case of shoulder arthroplasty, in a region that is proximate to or within the metaphysis (wide portion of the long bone between the epiphysis - head - and the diaphysis - the shaft).
  • this coupler may be positioned partially within the bone or on the cut surface of the bone for cases in which achieving anatomical match in a patient necessitates increased height on the superior aspect of the humerus.
  • FIG 15 show a variety of views of representative bone anchors in the form of diaphyseal stems in accordance with the disclosure.
  • the depicted shoulder prosthesis humeral stems are adapted for engagement with a coupler/metaphyseal shell.
  • the humeral stem component may be used with the various modular adapter components described herein in the manner described above to configure humeral stem with broad flexibility for relative positioning of the metaphyseal shell and prosthesis component relative to the stem.
  • the stem is comprised of a proximal region (about the upper 1/3 of the stem) that is adapted for alignment with the bone cut in the metaphysis and engagement to the shell, and a distal region (about the lower 2/3 of the stem) which is fit into the distal region of the diaphysis.
  • the shape of one or both the proximal and distal ends of the stem are adapted to be press-fit within the bone.
  • the proximal portion of the stem is selected to be a best fit for tight press-fit within the upper diaphysis/metaphysis of the bone.
  • the humeral stem includes an engagement feature, which is shown in representative FIG 15 as a female taper receiver on its proximal end that is adapted to receive a male insert, such as a tapered extension, to achieve engagement with the metaphyseal shell.
  • a male insert such as a tapered extension
  • the size, shape, location/position of the receiver and combinations of these features may vary to allow adaptability to the relative positioning of the engaged stem and metaphyseal shell.
  • the cross-sectional shape of the stem at its proximal end is generally trapezoidal and is adapted for achieving a desirable degree of fill of the upper end of the diaphysis and the metaphysis.
  • the degree of fill to be achieved with a stem ranges from 20 to 60%, and in some desirable embodiments about 40%.
  • the extent of fill ranges from and includes as a percentage of the void space in the engagement area of the bone, about 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, to 60.
  • the cross-sectional shape of the stem at its distal end is generally circular and may be adapted with fluting or other features to facilitate engagement of instruments for ease of removal as needed.
  • the stem component is adapted to enhance bony ingrowth and bone strength at regions of the humeral bone, for example at the proximal end only of the stem.
  • Surface features on the proximal and distal end may be included in some embodiments to facilitate fixation in the bone and facilitate subsequent removal, as in the instance of revision surgery.
  • the surface of the stem is configured with features and surface texturing to encourage bone growth along the proximal end of the stem, and the tapered distal end is devoid of texturing to discourage bone ingrowth and to enable easy disengagement of the stem from the distal diaphyseal portion in the event removal is necessary.
  • the entire lateral surface of the proximal end is textured to encourage bone ingrowth.
  • the stem has flattened panels on its sides and the flat areas of the proximal end are textured for bony ingrowth while the remainder of the lateral portions of the proximal end are not textured.
  • the length of the stem may be varied, and its proximal and distal dimensions and features may likewise be varied in accordance with those known in the art.
  • the girth of each stem size grows proportionally as the size increases, and the proximal and distal sections grow incrementally with size, with the distal length increasing at a greater rate relative to the proximal length. It will be apparent to one of ordinary skill that varying shapes and sizes of stems are possible and generally within the skill in the art.
  • the relative girth of the proximal end is selected to achieve the closest possible press fit within the bone to enhance stabilization, to provide maximal proximal surface contact to support the metaphyseal shell and to accommodate the fixation engagement between the shell and the stem.
  • Arrays may include the following possible set of stems: short stems that vary in length ranging from about 70 mm to 98 mm; standard stems that have a length of about 125 mm; and long stems that have a length of about 175 mm; Within each of these lengths, the stems further vary in size, with 8 representative sizes.
  • the stems may have length dimensions as follows: The stems may vary in size from small at a length of from 45 to 110 mm, and more particularly from about 60 to 95 mm, and more particularly from about 60 to 95 mm; to a medium length from about 110 to 130 mm, and more particularly from about 125 mm; to a long stem length from about 130 mm to about 180 mm, and more particularly from about 175 mm.
  • the stems may have proximal length dimensions as follows: The proximal portions of the stems may vary in size from 35 to 60 mm, and more particularly from about 40 to 54 mm.
  • the stems may have distal length dimensions as follows:
  • the distal portions of the stems may vary in size small distal length of from 25 to 50 mm, and more particularly from about 30 to 44 mm; to a medium distal length from about 70 to 90 mm, and more particularly from about 71 mm to about 85 mm; to a long distal stem length from about 120 mm to about 140 mm, and more particularly from about 121 mm to 135 mm.
  • the stems are provided to be suitable for placement within bone and engaged with a shell wherein the bone cut is at an angle of inclination from and including angle increments in between 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, and 145.
  • the stems have a shell-mating surface having an inclination that is about 135 degrees. It will be apparent to one of ordinary skill in the art that the stems could be provided having a different angle of inclination, and that the ultimate angle of inclination of an implant is determined based on the angle selected by the surgeon when making the bone cut.
  • the stems may have a cross sectional shape that is generally cylindrical, trapezoidal, rectangular or other, and combinations of these between the proximal and the distal ends.
  • coupler on its top or superior (articulation surface facing) side, a seat, such as a recess, that is adapted to accept both humeral head and humeral cup (reverse prosthesis) components.
  • the coupler addresses the mechanical challenge of orientation of spherical and most particularly non-spherical humeral head components using the coupler to achieve any anatomically desired offset in either or both the inferior/superior axis and anterior/posterior to achieve optimal anatomical alignment of the prosthetic articulation surface relative to the humeral bone.
  • the coupler includes an eccentric engagement feature on the back or inferior (bone facing) side, such as a standard taper (Morse-taper in some embodiments), that is selected for engagement with a bone stem, plug or cage (selected in size for anatomical match with the metaphyseal/diaphyseal portions of the long bone) to replicate and achieve native or normal humeral posterior and medial offset.
  • a standard taper Moorse-taper in some embodiments
  • the coupler is adapted to be recessed in bone in the absence of any stem, cage or plug type anchor and in others it may include a stem, cage or plug or taper feature for enhancing contact within the bone.
  • the current disclosure in various embodiments, provides a modular and convertible arthroplasty system that is low profile, having a substantial reduction of implant height as compared with what is known in the art. These embodiments are desirable for avoidance of distalization, particularly in reverse arthroplasty, enabling the surgeon to avoid mechanical and clinical problems associated with the rotational center of the joint, and enabling the use of other options for achieving soft tissue function to replace the rotator cuff.
  • the disclosure provides methods for implanting an arthroplasty system.
  • the methods include selecting from among at least prostheses components and one or more of coupler and anchor components, establishing at least the orientation of the major and minor axis of elliptical headed prostheses, and optionally any offset thereof relative to an anchor, and prepping and implanting one or more of a coupler and anchor prior to affixing and orienting the prosthesis.
  • the methods embody examples wherein a cup shaped prosthesis is initially or after a revision surgery affixed to a coupler component implanted by at least partial countersinking in the bone.
  • the surgical method for implanting a system comprising at least a coupler component and a prostheses component, and optionally an anchor involves access to the proximal humerus bone for removal of the native humeral head and replacement with a modular arthroplasty assembly in accordance with the disclosure.
  • a graphic depiction is provided of steps for implanting an arthroplasty system in accordance with the disclosure.
  • the steps for use of a trial for an anchor and for prepping the bone to receive an anchor may be eliminated, as well as the steps of determining offset of the prosthesis from a center point of an axis of an anchor.
  • no offset is required.
  • no coupler is used and only an anchor, such as a stem is used with a prosthesis.
  • no offset is required beyond selecting an anchor and implanting it with a desired angulation relative to the long bone and an axis oriented relative to the long bone.
  • the humeral head is surgically accessed; the anatomical neck of the humerus is cut (for example, at approximately 135 degrees based on the native anatomy, or at such other angle as may be determined by the surgeon with or without a cut guide) and the native humeral head is removed; a trial humeral head "sizer" or guide is positioned on the proximal humerus bone cut, the sizer being anatomically shaped like the intended prosthesis heads; the desired size and orientation are determined; the trial head sizer will have a central hole in it; after proper size and orientation of trial humeral head have been determined, the sizer is fixed in place and a pin is drilled through the center hole in the sizer; the sizer head is removed from over the pin, leaving the pin in place (a K-wire may be used); a reamer that is size dimensioned to match the size and shape of the metaphyseal shell is selected and placed over the central pin (for example, the size of the metaphyseal shell
  • the countersunk position of the coupler below the bone cut allows the surgeon to achieve a more anatomical configuration than other systems can achieve at time of primary or revision surgery.
  • the position and features of the coupler enable substitution of articulation surface prostheses, and as needed, removal of the shell during a revision.
  • removal of the shell enables replacement with a shell having an alternate offset to enable maximum flexibility for achieving desired anatomical structure in a revision surgery.
  • the coupler has a lateral edge that is in some exemplary embodiments roughened or porous coated to achieve bony ingrowth for reliable fixation, while the bottom of the coupler is smooth to prevent bony coupling in some embodiments, thus allowing for greater ease of removal from bone should that be necessary in a later procedure.
  • the coupler allows for minimal bone removal or manipulation at time of revision/conversion.
  • the use of the coupler trial with marking features enables precise and virtually unlimited increments of offset adjustability, eliminating need for large inventory of prosthetic heads and cups.
  • the options for adjustability are particularly wide when the coupler is used in combination with a suite of stems that are size and shape adapted for a wide range of patient anatomy.
  • a modular system for long bone arthroplasty comprising: an array of humeral head prosthesis components, each humeral head prosthesis component in the array having a convex articulation surface that is hemielliptical and defined by a major axis, a minor axis, an apex, and a base having an elliptical cross sectional shape defined by a major diameter along the major axis and a minor diameter along the minor axis, each humeral head prosthesis component in the array characterized by a ratio relationship of the minor diameter divided by the major diameter of the base, the array comprising a plurality of humeral head prosthesis components, each having a major diameter and a minor diameter that is different from each of the other humeral head prosthesis components in the array, wherein as the major diameter is increased the ratio of the minor diameter to the major diameter is decreased, whereby the humeral head prosthesis components vary from having a base with a more circular cross section
  • the system further comprises a coupler component selected from an array of coupler components where each coupler component in the array includes a humeral head prosthesis component engagement side and an opposite anchor component engagement side, and has sides bounded by a lateral edge.
  • the lateral edge may be one of cylindrical, frustoconical and frustohemispherical, and may have a surface treatment or texturing to encourage bony ingrowth or ongrowth.
  • the array of coupler components is characterized by having variably positioned anchor engagement features where each of at least two of the plurality of coupler components comprises at least one anchor engagement feature that is off-center from a center point the central engagement axis of the coupler component, and wherein the off-center engagement feature on each of the at least two coupler components is at a different distance in at least one dimension that is perpendicular to the central engagement axis.
  • the anchor component is selected from an array in which each anchor component has a proximal portion having a proximal surface for contacting at least a portion of the coupler component and a distal portion for positioning within bone, the proximal portion having an angle of inclination of from about 120 to about 145 degrees and comprising a coupler component engagement feature.
  • the humeral head prosthesis component includes on its engagement surface an engagement feature for concentric engagement with the coupler component.
  • the arthroplasty assembly achieves alignment of the bone articulation surface of the humeral head prosthesis component with the bone that is anatomically similar to a native long bone.
  • the position of the humeral head prosthesis component Prior to fixation within the bone, the position of the humeral head prosthesis component can be varied rotationally around a shared central engagement axis with the coupler component to achieve the desired orientation of the elliptical humeral head relative to the humerus and the glenoid. And the position of the anchor component relative to the coupler component can be varied in two dimensions on a plane that is perpendicular to the central engagement axis of the coupler and humeral head prosthesis components by selecting the coupler component from an array comprising a plurality of coupler components that include variably positioned anchor engagement features.
  • the anchor engagement component of the coupler component is radially offset from the central axis by from about 1 mm to about 20 mm.
  • the at least one anchor engagement feature of the disc shaped coupler component is radially offset from the central axis at a distance selected from one of about 1 mm to about 8 mm, and from about 1 mm to about 6 mm, and from about 1 mm to about 3 mm.
  • the coupler is in some embodiments adapted for use above the bone cut line, partially below the bone cut line, or as more particularly described and shown herein, countersunk essentially completely below the bone cut line.
  • the advantages of the coupler as described herein can be realized in any implant configuration whether above, or partially or fully recessed below the bone cut line, particularly to enable customized selection and fit of implant components without being constrained by inventory limitations or by less than desirable implant height, neck angle, version, and posterior and medial offset.
  • the use of the coupler with the elliptical heads enable surgical techniques wherein the coupler is completely or partially recessed within the humeral bone (i.e., below the cut line) to allow a greater range of options with respect to establishing the desired center of rotation in the shoulder joint.
  • the elliptical head is engaged concentrically with the coupler.
  • the modular system enables achievement of a more anatomically accurate joint replacement aimed at reducing clinically adverse consequences.
  • the coupler with its eccentric taper enables a wider range of selection of humeral head orientation without compromise of height, neck angle, version, and posterior and medial offset.
  • This offset function together with the anatomical benefits thereby attained, finally solves a vexing challenge in the art. That is, provision for truly adaptable and convertible, anatomically accurate implants - a challenge that has been heretofore addressed, inadequately at best, with either expansive prosthetic humeral head inventory and/or adjustable systems that sacrifice one or more of the anatomically desirable implant features such as component height, neck angle, version, and posterior and medial offset.
  • the individual components of the prosthetic implants disclosed herein may be made using a variety of materials, including metal, ceramic and plastic and combinations of these.
  • materials include but are not limited to: metals such as, for example, stainless steel, titanium alloys, cobalt alloys, cobalt chrome, superelastic metals, such as nitinol, polymers, such as polyester and polyethylene, polyether ether ketone (PEEK), carbon and carbon fiber materials.
  • Porous coatings may be provided for any or a portion of the components, and specifically as described herein or as otherwise known in the art.
  • the components may be provided with HA either dispersed on all or a portion of a surface, dispersed within all or a portion of the material of manufacture, and combinations of these.
  • the primary goal of this study was to quantify the ability of each prosthetic head type to replicate the normal anatomy when applied to a bone database representing a sample of the population.
  • 3D CT-scan based models were obtained of 79 proximal humeri from Caucasian subjects from the United States and Australia (47 male and 32 female; ages, 17-87 years, with an average age of 56 years). The models were obtained from a second party (Materialise, Leuven, Belgium) and were prescreened to exclude specimens with osteophytes or other obvious degenerative changes. A detailed anthropometric analysis of the humeral models that were used for this study is documented in a previously published article.
  • CAD Computer-aided design
  • SolidWorks 2014 Dassault Systemes S.A., Waltham, MA, USA
  • Anthropometric data shown in FIGS 19 - 22 was considered when creating both spherical and elliptical prosthetic heads, with the goal of maximizing the number of humeral specimens for each head type in which a good fit could be achieved.
  • the humeral head dimensional formulae were applied directly when creating the elliptical prosthetic heads. Referring again to FIG.
  • the measured parameters for both head types included the diameters at the base of the head in both the frontal (DF) and sagittal (DS) planes, the radii of curvature in both the frontal (ROCF) and sagittal (ROCS) planes, and humeral head height (HHH).
  • Four sets of prosthetic heads of each head type were created such that each set included heads that increased in size from small to large in 4, 3, 2, or 1mm increments.
  • the values for the smallest and largest heads (DF > 40mm, and DF ⁇ 56mm, respectively) were selected to cover the range of humeral head sizes based on the anthropometric data.
  • the number of heads per set was determined by the value by which the head size was incrementally increased: starting at 40mm, a 4mm incremental increase in head size based on DF resulted in a set with 5 heads (Set A), a 3mm incremental increase produced a set with 6 heads (Set B), a 2mm increase yielded 9 heads (Set C), and a 1mm increase produced a set with 17 heads (Set D).
  • the parameter measurements of the head types and sizes are provided in Table I, FIG. 16.
  • Prosthetic heads from each set were virtually implanted into each of the 79 humeral models.
  • the number of humeri within the study population whose anatomy could or could not be replicated within 3mm was recorded for each set of prosthetic heads, and percentages were calculated.
  • every one of the measured parameters (DF, DS, ROCF, ROCS, and HHH) had to be reproduced within 3mm of the native anatomy in order for the replication to be considered successful.
  • Contingency tables (2x2) were created, and the Fisher exact test was used to determine statistical significance when comparing the percentages of successful replication for each of the different sets of prosthetic heads (GraphPad Software, QuickCalcs; La Jolla, CA, USA).
  • a power calculator (G*Power 3, Version 3.1.9.2 for Mac OsX; Dusseldorf, Germany) was used to perform a post hoc power analysis. Statistical power of 0.8 or higher was considered adequate. In cases where the power was found to be inadequate, an a priori power analysis was performed using the known proportions to determine the minimum sample size that would be needed to adequately power future studies. The a priori power analyses were performed under the assumption of an a error probability of 0.05, an allocation sample size ratio (N2/N1) of 1, and a power (1 3 error probability) of 0.8.
  • an implant is anatomically correct, some implants in the art are designed to be usable in either a standard to a reverse configuration.
  • convertible implants allow the surgeon to convert by removing the standard prosthetic head from the stem and replacing the head with a cup (to mimic the glenoid) (examples within the art include convertible shoulder arthroplasty systems by Biomet, Zimmer, Tornier, Exactech). With such prostheses, the cup sits on top of the bone cut rather than being recessed within the bone.
  • a disadvantage of this technique and prosthesis design is that the humerus becomes overlengthened or distalized, predisposing the patient to nerve stretch injury, joint stiffness, and acromial fracture.
  • Arm lengthening, nerve palsies, joint instability, impingement, joint stiffness, acromial fractures, and difficulty with prosthesis conversion that ultimately leads to stem extraction and bone fracture are all examples of undesirable clinical outcomes resulting from current convertible and primary arthroplasty systems.
  • implant stability is addressed, in the context of long bones, through implant length, proximal diameter, and material selection and surface treatment that can enhance bony ingrowth on the implant.
  • implant surface features that encourage bony ingrowth and implant dimensions that are intended to achieve stability. While these features are helpful to encourage securement within bone, they are developed based on averages within a broad patient population, for example in terms of proximal humerus head and diaphysis dimensions and contribute to some of the other challenges of arthroplasty in that they provide only a limited range of possible device configurations and features for achieving bony fixation.
  • this disclosure provides a system that is modular and convertible and optimized achieve closer approximation of a patient's native anatomy, including avoidance of arm distalization, avoidance of surgery-related bone loss, while enabling a wider range of options for matching anatomy on during the index procedure as well as during surgical revision.
  • proximal to the extent used herein in connection with any object refers to the portion of the object that is closest to the operator of the object (or some other stated reference point), and to the extent used herein, the term “distal” refers to the portion of the object that is farthest from the operator of the object (or some other stated reference point).
  • surgeon and “operator” to the extent used herein are used interchangeably herein and each is intended to mean and refer to any professional or paraprofessional who delivers clinical care to a medical patient, particularly in connection with the delivery of care, including but not limited to a surgeon.
  • patient and “subject” to the extent used herein are used interchangeably herein and each is intended to mean and refer to any clinical animal subject, including a human medical patient, particularly in connection with the delivery of care thereto by anyone, including a surgeon or operator to the extent those terms are used herein.
  • an item may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
  • the terms “cephalad,” “cranial” and “superior” indicate a direction toward the head
  • the terms “caudad” and “inferior” and “distal” indicate a direction toward the feet.
  • the terms “dorsal” and “posterior” indicate a direction toward the back
  • the terms “ventral” and “anterior” indicate a direction toward the front.
  • lateral indicates a direction toward a side of the body
  • medial indicates a direction toward the mid line of the body, and away from the side
  • ipsalateral indicates a direction toward a side that is proximal to the operator or the object being referenced
  • transtralateral indicates a direction toward a side that is distal to the operator or the object being referenced.

Abstract

Cette invention concerne un système pour l'arthroplastie des os longs comprenant des composants de prothèse de tête humérale, et un ensemble composants de prothèse de tête humérale, chaque composant de prothèse de tête humérale dans ledit ensemble ayant une surface d'articulation convexe qui est semi-elliptique et définie par un axe majeur, un axe mineur, un sommet, et une base ayant une forme elliptique en coupe transversale définie par un diamètre majeur dans le sens de l'axe majeur et un diamètre mineur dans le sens de l'axe mineur, où l'ensemble composants de prothèse de tête humérale elliptiques permet un ajustement anatomique convenable et suffisant pour absorber une variation jusqu'à 3 mm maximum chez au moins 96 % d'une population de patients et jusqu'à 99 % d'une population de patients.
PCT/US2018/025486 2017-04-26 2018-03-30 Implants d'arthroplastie et méthodes d'orientation de prothèses articulaires WO2018200127A1 (fr)

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JP2020509420A JP2020518418A (ja) 2017-04-26 2018-03-30 関節形成インプラント及び関節人工装具を配向するための方法
EP18790699.5A EP3614973A4 (fr) 2017-04-26 2018-03-30 Implants d'arthroplastie et méthodes d'orientation de prothèses articulaires
CN201880035261.3A CN110678152A (zh) 2017-04-26 2018-03-30 关节成形术植入物和用于定向关节假体的方法

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EP3614973A1 (fr) 2020-03-04
JP2020518418A (ja) 2020-06-25
CN110678152A (zh) 2020-01-10
EP3614973A4 (fr) 2021-01-20

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