SCAPULAR ANCHOR FOR FIXING A GLENOID COMPONENT OF A SHOULDER JOINT PROSTHESIS TO A SCAPULA WITH COMPROMISED ANATOMY

Abstract

A scapular anchor for fixing a glenoid component of a shoulder joint prosthesis to a scapula with compromised anatomy. The scapular anchor comprises a glenoid support including a flange, and a pin integral with the flange for fixing the glenoid component to the scapular anchor. The flange comprises a distal surface structured to be at least partially in contact with a glenoid cavity of a scapula and a proximal surface opposite the distal surface. The scapular anchor comprises at least one customized portion specifically shaped to match a bone morphology of the scapula of a single patient with compromised anatomy. The at least one customized portion comprises the distal surface of the flange, being a customized distal surface of the flange, the customized distal surface being complementary shaped with respect to the glenoid cavity of the scapula of the single patient.

A related manufacturing method of a scapular anchor.

Claims

1. A scapular anchor for fixing a glenoid component of a shoulder joint prosthesis to a scapula with compromised anatomy, said scapular anchor comprising: a glenoid support including a flange, and a pin integral with the flange for fixing said glenoid component to said scapular anchor; wherein said flange comprises a distal surface structured to be at least partially in contact with a glenoid cavity of a scapula and a proximal surface opposite said distal surface; wherein said scapular anchor comprises at least one customized portion specifically shaped to match a bone morphology of the scapula of a single patient with compromised anatomy; wherein said at least one customized portion comprises the distal surface of said flange, being a customized distal surface of said flange, said customized distal surface being complementary shaped with respect to the glenoid cavity of the scapula of the single patient.

2. The scapular anchor of claim 1, further comprising an acromial support projection arranged to abut at an acromion process of said scapula.

3. The scapular anchor of claim 2, wherein said at least one customized portion further comprises the acromial support projection, being a customized acromial support projection.

4. The scapular anchor of claim 3, wherein said customized acromial support projection has a substantially tubular shape having a proximal end adjacent to said glenoid support and a distal end arranged to abut at said acromion process of said scapula.

5. The scapular anchor of claim 4, wherein a through hole extends between said proximal end and said distal end of said customized acromial support projection, for inserting a stabilization bone screw into said acromion process of said scapula.

6. The scapular anchor of claim 3, wherein said customized acromial support projection is made in one piece with said glenoid support.

7. The scapular anchor of claim 6, wherein said at least one customized portion further comprises a coracoid support projection arranged to abut at a coracoid process of said scapula, being a customized coracoid support projection.

8. The scapular anchor of claim 7, wherein said customized coracoid support projection has a substantially tubular shape having a proximal end adjacent to said glenoid support and a distal end arranged to abut at said coracoid process of said scapula.

9. The scapular anchor of claim 8, wherein a through hole extends between said proximal end and said distal end of said customized coracoid support projection, for inserting a stabilization bone screw into said coracoid process of said scapula.

10. The scapular anchor of claim 7, wherein said customized coracoid support projection is made in one piece with said glenoid support.

11. The scapular anchor of claim 7, wherein customized coracoid support projection is structurally distinct from the glenoid support and is selected from a plurality of projections with different dimensional and/or morphological features and is assembled to the glenoid support.

12. The scapular anchor of claim 1, wherein the distal surface of the flange comprises an at least partially irregular or trabecular structure to promote osteogenesis and bone integration.

13. The scapular anchor of claim 1, wherein the distal surface of the flange is directly designed based on a reconstruction of the compromised anatomy of the single patient, said reconstruction being implemented by computerized tomography.

14. The scapular anchor of claim 3, wherein said customized acromial support projection is structurally distinct from the glenoid support and is selected from a plurality of projections with different dimensional and/or morphological features and are assembled to the glenoid support.

15. The scapular anchor of claim 1, wherein said glenoid support comprises at least one hole for inserting stabilization bone screws to stabilize said glenoid support to said glenoid cavity.

16. The scapular anchor of claim 1, wherein said scapular anchor is made by EBM sintering or SLM manufacturing.

17. A manufacturing method of a scapular anchor for fixing a glenoid component of a shoulder joint prosthesis to a scapula with compromised anatomy; wherein said scapular anchor comprises a glenoid support including a flange, and a pin integral with the flange for fixing said glenoid component to said scapular anchor; wherein said flange comprises a distal surface structured to be at least partially in contact with a glenoid cavity of a scapula and a proximal surface opposite said distal surface; said manufacturing method comprising: customizing at least one customized portion including at least the distal surface of said flange, said at least one customized portion being specifically shaped to match a bone morphology of the scapula of a single patient with compromised anatomy, said distal surface being complementary shaped with respect to the glenoid cavity of the scapula of the single patient.

18. The manufacturing method of claim 17, wherein said scapular anchor further comprises an acromial support projection arranged to abut at an acromion process of said scapula, and wherein said at least one customized portion further comprises the acromial support projection, being a customized acromial support projection shaped to match a bone morphology of the single patient.

19. The manufacturing method of claim 18, wherein said scapular anchor further comprises a coracoid support projection arranged to abut at a coracoid process of said scapula, and wherein said at least one customized portion further comprises the coracoid support projection, being a customized coracoid support projection shaped to match a bone morphology of the single patient.

20. The manufacturing method of claim 17, further comprising: acquiring a bone morphology of a scapula by computerized tomography prior to customizing the at least one customized portion; and designing said at least one customized portion based on a reconstruction of a compromised anatomy of the single patient.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0038] FIG. 1 shows a proximal view of a scapular anchor for an artificial prosthesis of the shoulder manufactured according to the present invention;

[0039] FIG. 2 shows a first side view of the scapular anchor of FIG. 1;

[0040] FIG. 3 shows a distal view of the scapular anchor of FIG. 1;

[0041] FIG. 4 shows a second side view of the scapular anchor of FIG. 1;

[0042] FIG. 5 shows a proximal view of the scapular anchor of FIG. 1 fixed to a scapula model with compromised anatomy;

[0043] FIG. 6 shows a perspective view of the scapular anchor of FIG. 1 fixed to a scapula model with compromised anatomy;

[0044] FIG. 7 shows a proximal view in transparency of the scapular anchor of FIG. 1 fixed to a scapula model with compromised anatomy;

[0045] FIG. 8 shows a first side view in transparency of the scapular anchor of FIG. 1 fixed to a scapula model with compromised anatomy;

[0046] FIG. 9 shows a second side view in transparency of the scapular anchor of FIG. 1 fixed to a scapula model with compromised anatomy;

[0047] FIG. 10 is a side view showing detached parts of an anatomical total artificial shoulder prosthesis comprising a scapular anchor according to the present invention;

[0048] FIG. 11 is a side view showing detached parts of an inverse total artificial shoulder prosthesis comprising a scapular anchor according to the present invention.

DETAILED DESCRIPTION

[0049] With reference to said figures, reference number 1 wholly and schematically indicates a preferred embodiment of an anchor element manufactured according to the present invention for stably and safely fixing a prosthesis for the shoulder joint to a scapula having compromised bone anatomy.

[0050] In the following of the description, we will refer to this anchor element 1 with the easier term of scapular anchor.

[0051] Advantageously, the anchor 1 is a customizable component to be adapted to the compromised anatomy of the single patient.

[0052] The customization of the anchor can occur in the manufacturing step of the device or it can be directly carried out by the surgeon in the implantation step of the shoulder prosthesis.

[0053] In the first case, the anchor morphology is adapted for each patient based on a faithful reconstruction of the compromised scapular anatomy implemented by the modern computerized tomography techniques. Said approach allows shaping the anchor so that in the implantation step it perfectly matches the articular bone surface which it will have to be fixed to.

[0054] On the contrary, in the second case the anchor has portions, which are standardized but at the same time modulable, allowing the surgeon to choose the anchor configuration that best suits the patient's anatomy in the implantation step.

[0055] The preferred embodiment described in the following falls within the first customization case above described and in particular the anchor 1 is designed based on the model of a compromised scapular anatomy shown in FIGS. 5-9. This does not exclude other customization ways of the anchor according to the compromised anatomy of the single patient.

[0056] The anchor 1 shown in the appended figures comprises three portions for fixing to various bone sites of the scapula 50 with compromised anatomy: a glenoid support 2, a coracoid support projection 7 and an acromial support projection 8, arranged for fixing the anchor 1 to a glenoid cavity 51, to a coracoid process 52 and to an acromial process 53 of the scapula 50, respectively.

[0057] Other embodiments can provide a glenoid support 2 with one or more coracoid support projections 7 and/or one or more acromial support projection 8.

[0058] The anchor 1 is made of a biocompatible metal material, for instance of titanium or an alloy thereof and has a macro-rough finish, for instance according to what is described in U.S. Ser. No. 12/601,510 patent.

[0059] As it can be noticed from FIGS. 1-4 showing the anchor 1 in itself, the glenoid support 2 comprises a pin element 3 that is hollow and extended along a longitudinal axis X-X with a longitudinal dimension greater than its diameter or than its radial size.

[0060] The outer surface of the pin element 3 has longitudinal grooves to promote osteogenesis and bone integration when inserted in a hole obtained by the surgeon in the glenoid cavity 51 of the scapula 50.

[0061] The pin 3 has a tapered distal end 3a, an opposite flared proximal end 3c and is passed through by a fixing hole 3b. Within the hole 3b a glenoid component 100, 200 of a shoulder prosthesis is fixed.

[0062] A flange 4 is formed near the proximal end 3c. The above flange 4 is defined by a distal surface 5 and by a proximal surface 6, which connect to each other at a proximal edge 20.

[0063] The proximal edge 20 is defined in turn by a first lateral edge 20a opposite a second lateral edge 20b, an upper edge 20c and a lower edge 20d. The terms lower or upper are used here with reference to the prosthesis implanted on an upright patient, where the upper portion will face the head. Therefore, the preferential orientation of the anchor 1 corresponds to what is illustrated in FIG. 1.

[0064] The proximal surface 6 is a homogeneous and concave surface with a mirror pattern with respect to a symmetry axis Y-Y that is orthogonal to the axis X-X. On the bottom of the proximal surface 6 the flared proximal end 3c of the pin 3 and two stabilization through-holes 13 for the insertion of corresponding stabilization bone screws 12 to the glenoid cavity 51 open. The two stabilization holes 13 end up in the distal surface 5.

[0065] In the described preferred embodiment, the stabilization holes 13 are placed one above and one below the proximal end 3c of the pin 3.

[0066] Other arrangements and number of stabilization holes 13 can be provided in other embodiments according to the anatomic shape and quality of the glenoid bone tissue of the patient.

[0067] The distal surface 5, on the contrary, has a tendentially convex shape and a non-regular wavy pattern that reproduces the pathological morphology of the glenoid cavity 51 of the scapula 50. In other words, the distal surface 5 of the glenoid support 2 is designed so as to be complementary shaped with respect to the surface of the glenoid cavity 51, which it will have to perfectly match at the time of implantation.

[0068] In particular, in the described embodiment, which is customized to match the anatomic model of FIGS. 5-9, the distal surface 5 of the glenoid support 2 wraps a first portion of the pin 3 from the closest side to the lateral edge 20a and has a tapered pattern starting from the pin 3 towards the lower edge 20c and the lateral edge 20a up to a lateral wall 20e connecting with the lateral edge 20a. At the opposite side of the pin with respect to the axis Y-Y, namely the closest one to the lateral edge 20b, the distal surface 5 wraps the proximal end 3c of the pin 3 and has a tapered pattern towards the lateral edge 20b up to a lateral wall 20f connecting with the lateral edge 20b. The lateral walls 20e, 20f are placed on planes parallel to the plane formed by the axes X-X and Y-Y.

[0069] In alternative embodiments, the distal surface 5 may possibly or optionally not be customized to adapt to the single compromised scapular anatomy and have a standard shape, for instance plane or hemispherical, coupled in the implantation step with a seat suitably obtained at the glenoid cavity 51.

[0070] As it is clear from FIGS. 2 and 4, the pin element 3 passes through the distal surface 5 protruding away therefrom. The pin element 3 can be made in one piece with the flange 4 or constrained to the latter by interference.

[0071] At the upper edge 20c the coracoid 7 and acromial 8 support projections depart.

[0072] The support projections 7, 8 have a substantially tubular shape wherein a through-hole 11 extends from a proximal end 9 to a distal end 10. The proximal ends 9 of the support projections 7, 8 converge close to the axis Y-Y, but then the two support projections 7, 8 follow a divergent pattern away from the plane defined by the axes X-X and Y-Y and by the distal surface 5.

[0073] The through-holes 11 of the coracoid 7 and acromial 8 support projections allow the insertion of stabilization screws 12 for fixing to the coracoid 52 and acromial 53 processes, respectively.

[0074] In alternative embodiments the support projections 7, 8 may take up different shapes, not be provided with a through-hole 11 and be fixed in other ways known in the field, for instance by interference without using any fixing means.

[0075] In the described preferred embodiment, the coracoid 7 and acromial 8 support projections are made in one piece with the glenoid support 2. For instance, the projections can be made by EBM sintering or SLM manufacturing processes. Alternative embodiments can instead provide projections 7, 8 assembled with the glenoid support 2 in the implantation step of the anchor 1 so as to facilitate the surgery and possible future revisions.

[0076] Anyway, the support projections 7, 8 have a length and an orientation designed according to the compromised scapular anatomy 50 so that, when the anchor 1 is implanted, the distal end 10 abuts against the corresponding surface of the bone process 52, 53, which the projection 7, 8 is fixed to by means of the stabilization screw 12.

[0077] As it is clear from FIGS. 2 and 4, the distal end 10 of the coracoid support projection 7 and part of the distal surface 5 of the below glenoid support 2 have an irregular or trabecular structure 5a to promote osteogenesis and bone integration and was chosen to increase the contact friction of the distal end 10 and of the glenoid support 2 with respect to the surface of the coracoid process 7 and of the glenoid cavity 51 which it is respectively coupled to. This does not exclude that other surfaces or all of the surfaces in contact with the bone can be manufactured with a trabecular structure.

[0078] Therefore, each projection 7 or 8 has a shape that can be customized for any patient in the implantation step, by adjusting for instance length and/or orientation thereof, adapting it to the specific anatomy of the coracoid 52 and acromial 53 processes of the patient prior to the manufacturing step.

[0079] FIGS. 5-9 show the preferred embodiment of the scapular anchor 1 fixed to a scapula model with compromised anatomy, which it has been specifically designed for.

[0080] As it can be noticed from the above cited figures, the glenoid support 2 is implanted by making the distal surface 6, excluding the lateral walls 20e, 20f, match the glenoid cavity 51, which it perfectly coincides with. At the same time, the pin element 3 is inserted in a hole suitably formed in the glenoid cavity 51 and the stabilization screws 12 are inserted in the stabilization holes 8 and screwed to the bone below.

[0081] A further support is ensured by the two coracoid 7 and acromial 8 support projections that engage the distal end 10 against the respective coracoid 52 and acromial 53 process which they are fixed to by means of stabilization screws 12 inserted through the proximal end 9 into the through-hole 11.

[0082] Once the scapular anchor 1 has been fixed to the patient's scapula 50, as just described, the glenoid component 100, 200 of the shoulder total prosthesis is fixed thereto, said glenoid component 100, 200 will articulate with a humeral component 101, 201 previously fixed at the top of the humerus by means of a humeral stem 102, 202.

[0083] FIGS. 10 and 11 is a side view showing detached parts of a total artificial shoulder prosthesis, anatomic and inverse respectively, comprising a scapular anchor 1 according to the present invention.

[0084] It is described a method for manufacturing a scapular anchor for fixing a glenoid component of a shoulder joint prosthesis to a patient's scapula with compromised anatomy, of the type comprising the steps of providing a glenoid support, said glenoid support being defined by a pin for fixing said glenoid component to said scapular anchor and a flange integral with said pin, said flange having a distal surface adapted to be at least partially in contact with a glenoid cavity of said scapula and a proximal surface opposite said distal surface

[0085] The method for manufacturing a scapular anchor comprises a step of specifically providing at least one customized portion of said scapular anchor shaped to match the bone morphology of a scapula of a single patient with compromised anatomy and in that said at least one customized portion comprises at least one coracoid support projection arranged to abut at a coracoid process of said scapula.

[0086] The method for manufacturing a scapular anchor comprises a step of acquiring a bone morphology of a patient's scapula, for example by computerized tomography, prior to the step of shaping said custom portion of the scapular anchor.

[0087] It is further described a method for manufacturing a scapular anchor for fixing a glenoid component of a shoulder joint prosthesis to a patient's scapula with compromised anatomy; the method including the steps of: providing a glenoid support including a flange and a pin integral with the flange for fixing said glenoid component to said scapular anchor; said flange having a distal surface structured to be at least partially in contact with a glenoid cavity of said scapula and an opposite proximal surface; providing at least one customized portion of said scapular anchor specifically shaped to match the bone morphology of the scapula of a single patient with compromised anatomy; said at least one customized portion comprising at least one coracoid support projection having a substantially tubular shape integrally formed with said glenoid support and structured to abut at a coracoid process of said scapula.

[0088] According to the method for manufacturing a scapular anchor, a proximal end of said at least one coracoid support projection being formed adjacent to said glenoid support while a distal end of said at least one coracoid support projection being structured to abut to said coracoid process of said scapula; a through-hole extending between said proximal end and said distal end for receiving a stabilization bone screw into said coracoid process of said scapula.

[0089] The method for manufacturing a scapular anchor further comprises a step of acquiring a bone morphology of a patient's scapula, for example by computerized tomography, prior to the step of shaping said custom portion of the scapular anchor.

[0090] From the above description it is clear that the anchor according to the present invention achieves the intended purposes and several advantages, the main of which are hereinbelow listed.

[0091] Essentially, the solution of the present invention provides a customized scapular anchor in the design or implantation step to adapt to the particular compromised scapular anatomy of the single patient, detected for instance by computerized tomography.

[0092] Advantageously, the scapular anchor provides a glenoid support that can be complementary shaped with respect to the glenoid cavity which it perfectly matches once it has been implanted, thus promoting the implant stability.

[0093] Advantageously, the scapular anchor provides a coracoid support projection and/or an acromial support projection that offer a further support for the stabilization and fixing of the anchor to the scapula. Said projections can advantageously be customized in the design or implantation step to adapt to the particular anatomy of the coracoid and acromial processes of the patient.

[0094] Advantageously, the distal surface of the glenoid support and/or the second distal end of the coracoid and/or acromial support projection can have an irregular or trabecular structure to promote osteogenesis and bone integration.