Method for constructing a range of humeral components for shoulder joint prostheses

Abstract

A system and method for the field of humeral components for shoulder joint prostheses and, more specifically, to a method for constructing a range of humeral components intended to be inserted into the proximal region of the humerus during reconstructive shoulder surgery includes the following steps: obtaining a set (Evs) of statistical data relating to variables that can be used to characterise the geometry of a proximal humerus region from morphometric data (Dm) of proximal humerus regions belonging to a representative sample of a population; based on a statistical distribution, determining a set (G) of sizes forming the range of humeral components; for each of the sizes, determining a measurement (MiTn-n) for each of the variables, according to the set of statistical data; and for each of the sizes, producing a humeral component according to the measurement of each of the variables corresponding to the size.

Claims

1. A method for constructing a range of humeral components that are configured to be introduced into the proximal portion of the humerus during a shoulder reconstruction surgery, the method comprises: obtaining a set of statistical data relating to variables adapted to enable the characterization of a geometry of a humerus proximal portion, from morphometric data of humerus proximal portions belonging to a representative sample of a population; determining, from a statistical distribution, a set of sizes composing the range of humeral components; for each of the sizes, determining a measurement for each of the variables, according to the set of statistical data; and for each of the sizes, producing a humeral component according to the measurement of each of the variables corresponding to the size.

2. The method according to claim 1, wherein the variables adapted to enable the characterization of the geometry of a humerus proximal portion comprise one or more of the following variables: a medial offset, a posterior offset, a mechanical offset, a retrotorsion/bi-epicondylar, a retrotorsion/posterior, a cervico-diaphysial angle, a diameter of the joint surface, a thickness of the joint surface, an anteroposterior and mediolateral bulk of each of the transverse sections of the humeral component.

3. The method according to claim 1 further comprising determining, for each of the variables, the statistical distribution according to an average value and a standard deviation, relating to the variable, in the set of statistical data.

4. The method according to claim 1, wherein each humeral component of the range has a length smaller than 100 mm.

5. The method according to claim 4 further comprising obtaining at least one reference value of a torsion torque configured to cause loosening of a humeral component installed in a proximal portion of the humerus, wherein, the measurement for each variable, for each of the sizes, is determined according to the set of statistical data and according to the at least one reference value.

6. The method according to claim 5, wherein for each of the sizes, the measurement for each of the variables, according to the set of statistical data, is determined by: obtaining a three-dimensional model of the humeral component including sections distributed in different planes, each section being defined by a set of geometric parameters; determining, for each of the sections, the set of corresponding geometrical parameters, according to the set of statistical data relating to the variables adapted to enable the characterization of the geometry of a proximal portion of the humerus; and determining, for each of the geometrical parameters, by means of an interpolation function, the values of the parameter between each section, wherein for each of the sections, the set of corresponding geometrical parameters can be determined according to the set of statistical data relating to the variables adapted to enable the characterization of the geometry of a proximal portion of the humerus, and according to the at least one reference value.

7. The method according to claim 6, wherein the sections have a octagonal shape, each section being provided with fillets with configurable radii, the values of the configurable radii being selected according to the at least one reference value.

8. The method according to claim 1, wherein for each of the sizes, the measurement for each of the variables, according to the set of statistical data, is determined by: obtaining a three-dimensional model of the humeral component including sections distributed in different planes, each section being defined by a set of geometric parameters; determining, for each of the sections, the set of corresponding geometrical parameters, according to the set of statistical data relating to the variables adapted to enable the characterization of the geometry of a proximal portion of the humerus; and determining, for each of the geometrical parameters, by means of an interpolation function, the values of the parameter between each section.

9. A system for constructing a range of humeral components intended to be introduced into a proximal portion of a humerus during a shoulder reconstruction surgery, the system comprising: a database including a set of statistical data relating to variables adapted to enable the characterization of the geometry of a proximal portion of the humerus, from morphometric data of proximal portions of the humerus belonging to a representative sample of a population; a configurator configured to: determine, from a statistical distribution, a set of sizes composing the range of humeral components; and for each of the sizes, determine a measurement for each of the variables, according to the set of statistical data; and a production tool configured to produce, for each of the sizes, a humeral component according to the measurement of each of the variables corresponding to the size.

10. The system according to claim 9, wherein the configurator is configured to determine, for each of the sizes, the measurement for each of the variables, according to the set of statistical data, by: obtaining a three-dimensional model of the humeral component including sections distributed in different planes, each section being defined by a set of geometric parameters.

11. The system according to claim 10, wherein the configurator is configured to further determine, for each of the sizes, the measurement for each of the variables, according to the set of statistical data, by: determining, for each of the sections, the set of corresponding geometrical parameters, according to the set of statistical data relating to the variables adapted to enable the characterization of the geometry of a proximal portion of the humerus.

12. The system according to claim 11, wherein the configurator is configured to further determine, for each of the sizes, the measurement for each of the variables, according to the set of statistical data, by: determining, for each of the geometrical parameters, by means of an interpolation function, the values of the parameter between each section.

13. The method according to claim 1, wherein for each of the sizes, the measurement for each of the variables, according to the set of statistical data, is determined by: obtaining a three-dimensional model of the humeral component including sections distributed in different planes, each section being defined by a set of geometric parameters.

14. The method according to claim 13, wherein for each of the sizes, the measurement for each of the variables, according to the set of statistical data, is further determined by: determining, for each of the sections, the set of corresponding geometrical parameters, according to the set of statistical data relating to the variables adapted to enable the characterization of the geometry of a proximal portion of the humerus.

15. The method according to claim 14, wherein for each of the sizes, the measurement for each of the variables, according to the set of statistical data, is further determined by: determining, for each of the geometrical parameters, by means of an interpolation function, the values of the parameter between each section.

Description

DRAWINGS

(1) In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which:

(2) FIG. 1 is a flowchart illustrating one form of a construction method, according to the teachings of the present disclosure;

(3) FIG. 2 is a diagram of one form of a construction system, according to the teachings of the present disclosure;

(4) FIG. 3 is a schematic view of a metaphyseal cylinder and epiphysis sphere model, according to a reference construction, superimposed on an anatomical view of a typical humerus, in accordance with the teachings of the present disclosure;

(5) FIG. 4 is a schematic view of the metaphyseal cylinder and epiphysis sphere model, according to the reference construction, in accordance with the teachings of the present disclosure;

(6) FIG. 5 is a schematic view representing, in a detailed anatomical view of a typical epiphysis sphere, variables relating to said epiphysis sphere, in accordance with the teachings of the present disclosure;

(7) FIG. 6 is a schematic view representing, on a general anatomical view of a typical humerus, variables relating to said humerus, in accordance with the teachings of the present disclosure;

(8) FIG. 7 is a diagram representing the number of people, in a population sample, corresponding to different values in mm of medial offset from statistical data on a population sample, in accordance with the teachings of the present disclosure;

(9) FIG. 8 is a schematic three-dimensional view, derived from a finite element simulation, on which is represented the torsion torque likely to cause loosening of the humeral component when the latter is implanted in a humerus, in accordance with the teachings of the present disclosure;

(10) FIG. 9 is a diagram representing the interpolation functions for the following parameters: medial width ML_Med, lateral width ML_Lat, total medial width ML_Med_Total and total lateral width ML_Lat Total, in accordance with the teachings of the present disclosure;

(11) FIG. 10 is a diagram representing the interpolation functions for the following parameters: medial thickness AP_Med, lateral thickness AP_Lat and total thickness AP_Total, in accordance with the teachings of the present disclosure;

(12) FIG. 11 is a diagram representing the interpolation functions for the following parameters: medial radius of the octagons R_Med and lateral radius of the octagons R_Lat, in accordance with the teachings of the present disclosure;

(13) FIG. 12 is a diagram representing a three-dimensional model of a humeral component for a joint prosthesis (measurements expressed in mm), in accordance with the teachings of the present disclosure;

(14) FIG. 13 is a diagram, representing a proximal section of the three-dimensional model of a humeral component for a joint prosthesis, in accordance with the teachings of the present disclosure;

(15) FIG. 14 is a diagram representing a distal section of the three-dimensional model of a humeral component for a joint prosthesis (measurements expressed in mm), in accordance with the teachings of the present disclosure;

(16) FIG. 15 is a diagram representing the distribution and the relative positioning of the sections of the three-dimensional model of a humeral component for a joint prosthesis, in accordance with the teachings of the present disclosure;

(17) FIG. 16a is a three-dimensional view showing a humoral component of size 1, obtained by way of the method according to the teachings of the present disclosure;

(18) FIG. 16b is a three-dimensional view showing a humoral component of size 9, obtained by way of the method according to the teachings of the present disclosure;

(19) FIG. 17 is a three-dimensional view representing a range of humeral components for prostheses, obtained by way of the method according to the teachings of the present disclosure.

(20) The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

DETAILED DESCRIPTION

(21) The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

(22) FIG. 1 illustrates a construction method 100, for constructing a range of humeral components for prostheses, in particular the range shown in FIG. 17. The humeral components of the range are intended for a shoulder reconstruction surgery.

(23) Each humeral component of the range includes an endocanalar portion intended to be introduced into the proximal portion of the humerus. The range of humeral components includes a plurality of short humeral components—that is to say, typically having a length smaller than 100 mm—shown in FIG. 17. It is indeed advantageous to provide short humeral components because it is thus possible to facilitate the revision surgeries.

(24) The various endocanalar shapes of the humeral components of the range obtained by the implementation of the method provide the surgeons with the possibility of choosing a humeral component in said range, with a high probability that said humeral component is adapted to the morphology of the proximal portion of the humerus of the patient to operate. The recovery is typically 95% of the population for a range drawn with a size 1 having the parameters of μ−2σ and a size 9 having the parameters of μ+2σ, as detailed hereinafter in the description.

(25) The method includes a first step 110 during which morphometric data D.sub.M, corresponding to variables V.sub.n adapted to characterize proximal portions of the humerus belonging to a sample E representative of a population, are collected.

(26) At the end of step 110, a set E.sub.vs of statistical data, relating to the variables V.sub.n, is obtained.

(27) Advantageously, the method includes an optional second step 120, during which reference values V.sub.Er of torsion torques likely to cause loosening of humeral components, installed in proximal portions of the humerus belonging to a sample E′ representative of a population are obtained.

(28) The method includes a third step 130 during which, from a statistical distribution D.sub.T, a set G of sizes T.sub.n composing the range of humeral components is determined.

(29) The method includes a fourth step 140 during which, for each size T.sub.n of the set G, a measurement m.sub.iTn-n is determined, for each variable V.sub.n, according to the set E.sub.vs of statistical data, and, advantageously, according to the reference values V.sub.Er.

(30) The method includes a fifth step 150 during which, the range of humeral components is obtained, by producing, for each size T.sub.n of the set G, a humeral component according to the measurements m.sub.iTn-n relating to the variables V.sub.n corresponding to said size T.sub.n.

(31) Referring to FIG. 2, which schematically represents a construction system, according to one form. The system is in particular adapted to implement the construction method 100, to construct a range of humeral components for prostheses.

(32) The system allows facilitating the steps of designing the range of humeral components, by providing in particular the possibility of modifying and evaluating the geometry of each humeral component designed according to the morphometric data and the experience of surgeons.

(33) The system includes a database 210 including the morphometric data D.sub.M, corresponding to the variables V.sub.n adapted to characterize proximal portions of the humerus belonging to the sample E.

(34) The system also includes a model 220 adapted to describe, for each size T.sub.n of the set G, the measurements m.sub.iTn-n, for each variable V.sub.n, according to the set E.sub.vs of statistical data, and, advantageously, according to the reference values V.sub.Er.

(35) The system includes a configurator 230, coupled to the database 210 and to the model 220, and adapted to define, for each size T.sub.n of the set G, a humeral component according to the measurements m.sub.iTn-n relating to the variables V.sub.n corresponding to said size T.sub.n.

(36) The configurator 230 may advantageously be coupled to a computer-aided design software, in order to allow, for example, automatically simulating the humeral components of the set G, according to the available morphometric data and laws.

(37) The system includes a production tool 240, coupled to the configurator 230, configured to produce, for each size T.sub.n of the set G, a humeral component according to the measurements m.sub.iTn-n relating to the variables V.sub.n corresponding to said size T.sub.n.

(38) The system advantageously includes a tool for taking into account feedbacks 250 to collect new sets of statistical data, and coupled to the configurator 230 so as to allow the latter to take into account said new sets of statistical data.

(39) Referring now to FIGS. 3 to 6, there is represented a reference construction for a proximal portion of a humerus. A reference construction for a proximal portion of the humerus is a geometric model comprising geometric objects, characterized by a set of variables whose values allow describing geometries of proximal portions of the humerus.

(40) More particularly, in FIGS. 2 to 5, a model of metaphyseal cylinder 12 and epiphysis sphere 14 is represented.

(41) In this reference construction, the metaphyseal cylinder 12 is represented by a least squares cylinder, typically comprised between the planes XX′ and YY′, orthogonal to the diaphyseal axis of the humerus, and substantially distant respectively by 65 mm and by 105 mm, relative to the top of the joint surface C—also called Hinge point, and noted C in FIG. 6.

(42) The epiphysis sphere 14 is represented by a least squares sphere passing through the points palpated on the joint surface of the epiphysis sphere of the humerus 10.

(43) In FIGS. 4 and 5, variables relating to the metaphyseal cylinder 12 and the epiphysis sphere 14 are also represented.

(44) In FIGS. 3 to 6, more particularly, are represented:

(45) the medial offset ΔM, corresponding to the distance between the center of the humeral head—that is to say, the center of the least squares sphere—and the diaphyseal axis projected in the frontal plane;

(46) the posterior offset ΔP, that is to say the distance between the center of the humeral head—that is to say the center of the least squares sphere—and the diaphyseal axis projected in the sagittal plane;

(47) the mechanical offset O.sub.MC, that is to say the distance between the center of the humeral head—that is to say the center of the least squares sphere—and the diaphyseal axis; the mechanical offset O.sub.MC can in particular be determined from the following mathematical expression:
O.sub.MC=√{square root over (O.sub.MD.sup.2+O.sub.P.sup.2)}

(48) the retrotorsion/bi-epicondylar β.sub.1, that is to say the angle between the projection in the axial plane of the neck of the humerus and the bi-epicondylar line;

(49) the retrotorsion/posterior β.sub.2, that is to say the angle between the axis of the neck of the humerus and the two most posterior points of the distal joint surface of the humerus;

(50) the cervico-diaphyseal angle α between the diaphyseal axis of the humerus and the normal axis OO′;

(51) the diameter D.sub.SA of the joint surface, namely the distance between the point C and the point D;

(52) the thickness E.sub.SA of the joint surface.

(53) Also, according to the previously-described reference construction example, the variables V(n) of the set EVS of statistical data considered are therefore the following ones:

(54) the medial offset O.sub.MD,

(55) the posterior offset O.sub.P,

(56) the mechanical offset O.sub.MC,

(57) the retrotorsion/bi-epicondylar β.sub.1,

(58) the retrotorsion/posterior β.sub.2,

(59) the cervico-diaphyseal angle α,

(60) the diameter D.sub.SA of the joint surface,

(61) the thickness E.sub.SA of the joint surface.

(62) The set E.sub.VS of statistical data, relating to morphological variables V.sub.n of proximal portions of the humerus belonging to the sample E, is thus determined, for said variables.

(63) In one form, the set E.sub.VS of statistical data, relating to morphological variables V.sub.n of proximal portions of the humerus belonging to the sample E, is thus determined in particular from information, for example comprised in a database, grouping together values obtained for said variables V.sub.n during statistical studies.

(64) Thus, the diagram illustrated in FIG. 7, representing the number of persons corresponding to different values in mm of medial offset O.sub.MD can be obtained from statistical data on the sample E, grouped together in a database.

(65) During the optional second step 120, during which reference values V.sub.Er of torsion torques likely to cause loosening of humeral components, installed in proximal portions of the humerus, are determined.

(66) FIG. 8 represents a schematic three-dimensional view, derived from a finite element simulation, on which is represented a torsion torque C.sub.T likely to cause loosening of said humeral component when the latter is implanted in a humerus.

(67) These data can also be obtained, experimentally, using a torque wrench so as to determine said reference values on the torsion torques likely to cause loosening of a humeral component implanted in the proximal portion of a humerus.

(68) During the third step 130, the set G of sizes T.sub.(n), comprised in the range of humeral components, is determined, according to the set E.sub.VS of statistical data, from the statistical distribution D.sub.T.

(69) A size is an arbitrary value referring to a set of values for the different variables V.sub.n, the diaphyseal dimensions being predominant.

(70) In one form, the statistical distribution D.sub.T is determined, for each of the variables V.sub.n, according to the average value M and to the standard deviation σ, relating to said variable V.sub.n, in the set of statistical data for the sample E.

(71) Thus, for each morphological variable V.sub.n for the sample E, for a range including 5 different sizes, the statistical distribution DT may be as follows:

(72) TABLE-US-00001 Size 1 average value M − 2 × standard deviation σ Size 3 average value M − 1 × standard deviation σ Size 5 average value M Size 7 average value M + 1 × standard deviation σ Size 9 average value M + 2 × standard deviation σ

(73) The following table groups together the average values and the standard deviations according to the previously-described statistical distribution DT, for each morphological variable V.sub.n for the sample E, obtained from statistical data collected from medical studies and tests:

(74) TABLE-US-00002 M σ M − 2 × σ M + 2 × σ medial offset O.sub.MD 6.2 mm 1.9 mm  2.4 mm 10.0 mm posterior offset O.sub.P 1.7 mm 1.7 mm −1.7 mm  5.1 mm mechanical offset O.sub.MC 6.4 mm 2.5 mm  2.9 mm 11.2 mm retrotorsion/bi-  17.9° 13.7°  −9.5°  45.3° epicondylar β.sub.1 retrotorsion/posterior 23°  12.5° −2°  48°  β.sub.2 cervico-diaphyseal 134.2°  4.9° 123.8° 144.6° angle α diameter D.sub.SA 44.2 mm  4.0 mm 36.2 mm 52.2 mm thickness E.sub.SA 16.4 mm  1.7 mm 13.0 mm 19.8 mm

(75) Referring now to FIGS. 12 to 15, in which, in one form, a three-dimensional model of a humeral component for a joint prosthesis is represented.

(76) The model includes sections S.sub.n distributed in different planes P.sub.n. In the example represented in FIGS. 11 to 14, nine sections S.sub.1 . . . S.sub.9 are distributed in parallel planes P.sub.1 . . . P.sub.9 orthogonal to the vertical axis XX′. The sections S.sub.1 . . . S.sub.9 are spaced apart, in pairs, by a constant distance, proportional to the total length of the humeral component. Six sections S.sub.10 . . . S.sub.11 are distributed in planes P.sub.10 . . . P.sub.15. The plane P.sub.10 is inclined according to an angle α.sub.10 with respect to the plane P.sub.9. The plane P.sub.11 is inclined according to an angle α.sub.11 with respect to the plane P.sub.10. The plane P.sub.12 is inclined according to an angle α.sub.12 with respect to the plane P.sub.11. The plane P.sub.13 is inclined according to an angle α.sub.13 with respect to the plane P.sub.12. The plane P.sub.14 is inclined at according to an angle α.sub.14 with respect to the plane P.sub.13. The plane P.sub.15 is inclined according to an angle α.sub.15 with respect to the plane P.sub.14.

(77) In one form, all of the angles α.sub.10 . . . 15 are substantially equal. The section S.sub.15 is represented in FIG. 13, the section S.sub.1, in FIG. 14. The sections S.sub.n have a substantially octagonal shape, provided with configurable fillets. Each section S.sub.n can be described by a set of parameters P.sub.Sn:

(78) a lateral radius RL.sub.n,

(79) a medial radius RM.sub.n,

(80) a lateral distance MLM.sub.n,

(81) a total lateral distance MLMT.sub.n,

(82) a medial distance MLL.sub.n,

(83) a total median distance MLLT.sub.n,

(84) a lateral distance APL.sub.n,

(85) a medial distance APM.sub.n,

(86) a total distance APT.sub.n.

(87) Also, for each size T.sub.(n) of the set G, the set of parameters P.sub.Sn is determined, for each of the sections S.sub.n, according to the set E.sub.VS of statistical data. Then, for each parameter P.sub.Sn describing the sections S.sub.n, the variations of the value of said parameter between each plane P.sub.n are interpolated.

(88) FIGS. 9 to 11 represent various interpolation functions F.sub.PSn specific to the different parameters P.sub.Sn, for the size 5. The interpolation functions F.sub.PSn are typically 3.sup.rd degree interpolation functions (thus with 2 inflection points).

(89) In an advantageous form, for each size T.sub.(n) of the set G, the set of parameters P.sub.Sn is determined, for each of the sections S.sub.n, according to the set E.sub.VS of statistical data and according to the reference values V.sub.Er of torsion torques likely to cause loosening of humeral components, determined during the second step 120.

(90) More particularly, the lateral radius RL.sub.n and the medial radius RM.sub.n for each of the sections S.sub.n can be determined according to the reference values V.sub.Er of the torsion torque forces likely to cause loosening of humeral components.

(91) Thus, the values of the lateral radius RL.sub.n and of the medial radius RM.sub.n for each of the sections S.sub.n are for example determined according to the reference values V.sub.Er and therefore according to the rotational stability need:

(92) the smaller the value of the lateral radius RL.sub.n and/or of the medial radius RM.sub.n, the greater said rotational stability will be, which is desirable for the proximal area of the humeral component;

(93) the larger the value of the lateral radius RL.sub.n and/or of the medial radius RM.sub.n, the lower the rotational stability will be, which is desirable for the distal area of the humeral component so as to facilitate insertion into the humerus and to limit stress deflection problems, more commonly referred to as “stress-shielding”.

(94) The range of humeral components is obtained by producing, for each size T.sub.(n) of the set G, a humeral component according to the corresponding model obtained, as previously described.

(95) After having implemented the construction method, we thus obtain the range of short humeral components adapted to the morphologies of the patients, the range of humeral components allowing the surgeons to have, for each patient, an optimized short humeral component.

(96) FIG. 16a shows, in particular, an example of a humoral component of size 1 (measurements expressed in mm) obtained by way of the method disclosed herein. FIG. 16b shows, in particular, an example of a humoral component of size 9 (measurements expressed in mm) obtained by way of the method disclosed herein.

(97) Unless otherwise expressly indicated herein, all numerical values indicating mechanical/thermal properties, compositional percentages, dimensions and/or tolerances, or other characteristics are to be understood as modified by the word “about” or “approximately” in describing the scope of the present disclosure. This modification is desired for various reasons including industrial practice, manufacturing technology, and testing capability.

(98) The description of the disclosure is merely exemplary in nature and, thus, variations that do not depart from the substance of the disclosure are intended to be within the scope of the disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure.

(99) As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean “at least one of A, at least one of B, and at least one of C.”