Acetabular prosthesis system and designing method thereof

Abstract

Aspects in accordance with the present invention pertain to a prosthesis system comprising a plurality of modules, each of said modules being adapted for separate and appositional fixation thereof to a defective pelvis bone, such that when all the modules have been fixed to the pelvis bone, the modules communicate by a mating interface, thereby forming an acetabular prosthesis that is adapted to reconstruct an acetabulum and / or to augment the pelvis bone.

Description

[0001] TITLE OF THE INVENTION

[0002] ACETABULAR PROSTHESIS SYSTEM AND DESIGNING METHOD THEREOF

[0003] FIELD OF THE INVENTION

[0004] The present invention relates to medical devices for hard tissue surgery, particularly to those for use with human bone, and more particularly to those used for reconstructing an acetabulum and / or augmenting a pelvis bone. The present invention further relates to methods of designing and manufacturing such devices, particularly to those which are computer-aided or computer- implemented.

[0005] BACKGROUND OF THE INVENTION

[0006] Femur and pelvis’s connection is that of a ball and a socket. Pelvis bone defects, inclusive of bone spurs, tumor, and bone decay, as well as other damages sustained by the bone’s structure, may require a treatment by total hip arthroplasty (THA). Generally, the THA entails fixing an acetabular prosthesis to the patient’s pelvis bone. A conventional acetabular prosthesis comprises a shell component and an augmentation component. The shell component is a cup-like component adapted to cover the void defined by the patient’s acetabulum, thereby acting the socket’s role to engage with a prosthesis femoral head in place of the natural acetabulum. The augmentation component reinforces and reconstructs the structural weakness caused by the pelvis bone defect. Conventionally, the THA also entails reaming, rasping, or otherwise preparing the bones surrounding the area of fixation. Such bone preparation is necessary for making way for the acetabular prosthesis to reach the area of fixation and / or for removing the defective part of the bone.

[0007] Implanting conventional acetabular prostheses causes post-operative wear and tear upon the patient’s bone at or near the area of fixation, leading to pain and impaired utility and entailing a revision surgery, also referred to as the second THA. The revision surgery usually leads to further bone preparation (i.e., bone removal) and replacement of the acetabular prosthesis with a new one. Depending on the circumstances, the third or fourth THAs may be required.

[0008] In receiving a THA, the patient’s quality of life may be impacted by factors including anatomical fitness, invasiveness, and operation time. Anatomical fitness refers to, among others, suitability of the prosthesis’s design for the patient’s anatomical features which is dictated by complexity of the bone’s natural configuration and / or the sustained damage. Anatomical fitness is oftentimes affected by human imprecision in the implantation, however slight. Poor anatomical fitness causes post- operative pain or decreased hip utility and increases the likelihood of revision surgery.

[0009] Invasiveness refers to, among others, the required width of incision and the extent to which the nearby healthy bones / tissues must be ‘prepared’ (e.g., be rasped, reamed, or removed) to apply the prosthesis. Great invasiveness is associated with slow post-operative recovery along with the risk of infection and similar complications.

[0010] Operation time relates to both the above two problems and more. A prosthesis having poor anatomical fitness takes longer time to implant and often requires the surgeon to manually modify it during the operation. Invasiveness adds to the operation steps which naturally increases the operation time. Furthermore, the operating surgeon may be compelled to spend a longer time than planned due to the lack of skills and / or effective guiding means. Long operation time is also associated with slow recovery and risks of infection.

[0011] These factors are addressed by existing standardized and customized systems, with vastly different effectiveness. Compounding with the complexity of the bone defect, solving all the problems are considered in the arts as conflicting pursuits.

[0012] US 7,985,260 B2 teaches an acetabular prosthesis system that is coupled to the ‘prepared’ acetabular. The system comprises a shell component having a plurality of apertures or slots with threaded fasteners used to fix the shell component and an augmentation component together.

[0013] US 8,828,089 B2 teaches an acetabular augment that is designed to have the buttress area matching to the outer surface of a conventional acetabular component with a coupling arrangement for coupling a buttress member with an affixation member to permanently affix them in a fixed angular position.

[0014] US 10,751 , 186 B2 teaches a system, method, and augment for supporting an acetabular shell at a hip bone. The acetabular augment comprises a coupling element having a bulbous shape to rest in a chamber.

[0015] US 10,960,454 B2 teaches a method of making a custom acetabular implant. The method comprises acquiring and analyzing tomography data of the patient and obtaining geometry and measurement parameters of the patient’s pelvic anatomy. The method further includes shaping the blank acetabular prosthesis using a custom deforming fixture such that the shaped acetabular prosthesis has a final shaped geometry and measurement parameters to substantially match the patient's pelvic anatomy relative to the patient's acetabulum.

[0016] US 2021 / 0330463 Al teaches a method for manufacturing a prosthetic system. The method comprises determining a cup’s position and orientation to set a base of an augment, and then the contour of the patient’s pelvis based on the patient’s anatomical landmarks. The resulting system comprises a shell and an additive-manufactured augment with patient-specific contours.

[0017] Other prior arts known to the present inventors are:

[0018] W Steven Borland, Raj Bhattacharya, James P Holland, and Nigel T Brewster, Use of porous trabecular metal augments with impaction bone grafting in management of acetabular bone loss Early to medium-term results, Acta Orthopaedica 2012; 83 (4): 347-352;

[0019] Kong K, Zhao C, Chang Y, Qiao H, Hu Y, Li H and Zhang J (2022) Use of Customized 3D- Printed Titanium Augment With Tantalum Trabecular Cup for Large Acetabular Bone Defects in Revision Total Hip Arthroplasty: A Midterm Lollow- Up Study. Pront. Bioeng. Biotechnol .;

[0020] Henri Migaud, Harold Common, Julien Girard, Denis Huten, Sophie Putman, Acetabular reconstruction using porous metallic material in complex revision total hip arthroplasty: A systematic review, Orthopaedics & Traumatology: Surgery & Research, Volume 105, Issue 1, Supplement, 2019, Pages S53-S61; and

[0021] Burastero, G., Cavagnaro, L., Chiarlone, F. et al. Clinical study of outcomes after revision surgery using porous titanium custom-made implants for severe acetabular septic bone defects. International Orthopaedics (SICOT) 44, 1957-1964 (2020).

[0022] None of the foregoing prior arts satisfactorily addresses the present problem, despite the demand for a more effective prothesis system for acetabular augmentation and / or reconstruction.

[0023] SUMMARY OF THE INVENTION

[0024] An object of the present invention is to provide a prosthesis system and a designing method thereof that effectively solves the abovementioned technical problems.

[0025] In the first aspect, an embodiment is a prosthesis system comprising a plurality of modules, each of said modules being adapted for separate and appositional fixation thereof to a defective pelvis bone, such that when all the modules have been fixed to the pelvis bone, the modules communicate by a mating interface, thereby forming an acetabular prosthesis that is adapted to reconstruct an acetabulum and / or to augment the pelvis bone.

[0026] Preferably, the mating interface is further adapted correspondingly to a predetermined sequence by which the modules are to be appositionally fixed to the pelvis bone.

[0027] Preferably, the mating interface is disposed so as to avoid overlapping the acetabular prosthesis’ center of rotation in relation to a femoral head.

[0028] Optionally, the mating interface is adapted so as to provide a space between the modules when the acetabular prosthesis is formed. In such an embodiment, it is preferable that the space’s width is in the range of 1 - 4 millimeters.

[0029] Optionally, the acetabular prosthesis further comprises an extension to rest on the pelvis bone, thereby providing the acetabular prosthesis with additional stability in relation to the pelvis bone. In such an embodiment, it is preferable that the extension is further adapted to be fixed to the pelvis bone.

[0030] In the second aspect, an embodiment is preferably a prosthesis system comprising a plurality of modules. Each of said modules comprises: (i) a shell component’s section; (ii) an augmentation component’s section; and (iii) a connector by which the plurality of modules may communicate, thereby forming an acetabular prosthesis comprising a shell component and an augmentation component. Further, the modules are adapted for separate and appositional fixation to a pelvis bone. And when the acetabular prosthesis is formed, the shell component and the augmentation component are disposed such that the augmentation component is substantially interposed between the shell component and the pelvis bone.

[0031] Preferably, in each of the modules, the shell component’s section and the augmentation component’s section are layered substantially along a direction of acetabular support when the acetabular prosthesis is formed.

[0032] Preferably, the connector is further adapted correspondingly to a predetermined sequence by which the modules are to be appositionally fixed to the pelvis bone.

[0033] Preferably, the connector is defined so as to avoid overlapping the acetabular prosthesis’ center of rotation in relation to a femoral head. Optionally, in each of the modules, the shell component’s section and / or the augmentation component’s section is adapted for separate and appositional fixation to a pelvis bone by way of providing one or more apertures, such that through each of said aperture a screw may be inserted.

[0034] Optionally, the connector is adapted so as to provide a space between the modules when the acetabular prosthesis is formed. In such an embodiment, it is preferable that the space’s width is in the range of 1 - 4 millimeters.

[0035] Optionally, the connector is adapted for mechanical or chemical sealing.

[0036] Optionally, the connector’s surface is adapted to promote friction necessary to effect the said mechanical sealing.

[0037] Optionally, the acetabular prosthesis further comprises an extension to rest on the pelvis bone, thereby providing the acetabular prosthesis with additional stability in relation to the pelvis bone. In such an embodiment, it is preferable that the extension is further adapted to be fixed to the pelvis bone, and it is more preferable that the extension is porous.

[0038] Preferably, the shell component comprises a femur-facing surface that is adapted to effectively promote friction between the shell component and a liner.

[0039] Preferably, the shell component or the augmentation component comprises a femur-facing surface that is adapted to promote adhesion between an orthopedic bonding material and said femurfacing surface.

[0040] Preferably, the shell component or the augmentation component comprises a pelvis-facing surface that is porous.

[0041] The porosity that is applicable to any of embodiments includes but is not limited to a non- uniform structure, an octet truss, gyroid, diamond, neovius, IWP, hexagonal, decahedral, and dodecahedral structures.

[0042] The porosity may be applied to an embodiment by subtracting the surface of prosthesis and / or adding material to the surface of prosthesis for manufacturing porous surface. The manufacturing method could be a physical method such as Additive Manufacturing (Electron Beam Melting (EBM), Selective Laser Melting (SLM), Selective Laser Sintering (SLS), Direct Metal Laser Sintering (DMLS), Directed Energy Deposition (DED), Fused Deposition Modeling (FDM), Fused Filament Fabrication (FFF), Binder jetting, Stereolithography (SLA), Digital Light Processing (DLP)), Subtractive manufacturing (Milling, Machining, CNC routing, Plasma cutting,

[0043] SUBSTITUTE SHEET (RULE 26) Laser etching or chemical method such as Acid etching, Anodization, Polymer (biocompatible) coating, Ceramic (biocompatible) coating, Plasma spray, magnetron sputtering, Chemical Vapor Deposition (CVD), Physical vapor deposition (PVD), or existing coating techniques. The average pore size of the porous surface is 100-1200 microns, preferably 200-800 microns. The thickness of porous surface is 100-4000 microns, preferably 1000-2000 microns.

[0044] Optionally, the porosity is a nano-porous surface, an antimicrobial porous surface, or a bioactive surface. Those surfaces may be applied to an embodiment by surface modification technologies such as the HA coating, polymer coating, drug delivery technology, and anodizing technique.

[0045] In the first or second aspect, the prosthesis system may preferably further comprise a surgical guide for guiding the drilling trajectories for more precise fixation.

[0046] Particularly, the prosthesis system may further comprise an assisted surgical guide for placement on said a modular augmented system. Said the assisted surgical guide comprises implantfacing surface and one or more trajectory guiding element corresponding with predetermined fixation trajectory. The said assisted surgical guide is partially made from a first material.

[0047] Also particularly, regarding the said assisted surgical guide, the implant-facing surface corresponds to at least partially of shell component and / or augmentation component.

[0048] Also particularly, regarding the said assisted surgical guide, said implant-facing surface form an extension to correspond with extension of modular augmented system.

[0049] Also particularly, the said assisted surgical guide further comprises guide member which partially made from a second material that harder than the first material.

[0050] Optionally, the said implant-facing surface form an extension to correspond with extension of modular augmented system.

[0051] Preferably, the said assisted surgical further comprises guide member which partially made from material that harder than said assisted surgical.

[0052] Appositional fixation according to the first and second aspects refers to fixing the modules side by side onto the pelvis bone, and upon executing the said fixation assembling the acetabular prosthesis on the pelvis bone.

[0053] The concept of appositional fixation is distinct from the prior-art modular systems whereby the acetabular prostheses must be assembled ex-situ before being fixed to the patient’s pelvis bone, or whereby the acetabular prostheses must be assembled by stacking the modules in-situ, i.e., by mounting the first module upon the pelvis bone, and then mounting the second module upon the first module, and so on.

[0054] In all those prior-art modular systems, each of the ‘modules’ embodies separate functionalities. For example, the system according to US 7,985,260 B2 has a shell component and an augmentation component. The shell component receives the prosthetic femoral head; the augmentation component is received by the pelvis bone. The shell component and the augmentation component are fabricated separately and later assembled by way of skewering threaded fasteners through the stacked shell and augmentation components to form a complete system. Other prior modular systems, such as Migaud etal. (2019) (full citation is provided above), may involve a shell component upon which a plurality of augmentation components may be likewise stacked and fastened for complex augmentation.

[0055] On the other hand, in an embodiment according to the first or second aspect, the concept of appositional fixation prefers a plurality of modules, each of said modules embodying the functionality of shell and the functionality of augmentation. The present inventors found that such arrangement provides remarkable decrease in the operation time and invasiveness. Also in such an embodiment, the mating interface or connector guides the fixation / assembly so that such is executed quickly and precisely. Such precision provides excellent versatility for the nature of defects, compensation for the surgeon’s skills, control of human errors, stability upon fixation, and promotes anatomical fitness. The details of these technical advantages will become apparent later in the Detailed Description.

[0056] Embodiments according to the first and second aspects are achieved and enabled by embodiments according to the third and fourth aspects.

[0057] In the third aspect, an embodiment is a method of making the prosthesis system, said system comprising a step of (a) determining the defective bone from medical images, (b) determining the shell component’s position and angle, (c) defining the augment component to fill the defective bone, (d) determining the screw trajectories for fastening the prosthesis, and (e) generating the separation plane to separate a prosthesis into plurality of modules conducive to separate implantation. Each of the modules comprises a shell component’s section, an augmentation component’s section, and a connector with which the plurality of modules communicates, thereby forming a shell component and an augmentation component which are disposed so as to share a substantially common center. Said method comprises configuring the connector based upon the following parameters: (i) placement of fastening locations on the prosthesis, (ii) conditions of the bone on each plurality of the separate implant components, (iii) distribution of mechanical stress.

[0058] Preferably, said step of determining the shell component’s position from medical images, thereby making the hemisphere correspond to the center of rotation on the other side of the femoral head.

[0059] Preferably, said step of determining the shell component’s position from medical images, thereby making hemisphere to arrange the angle of the shell component in 30 - 50 degrees abduction and 5 - 25 degrees anteversion.

[0060] Preferably, said step of defining the augment component to fill the defective bone, thereby making a constraint defect points from the predetermined center of rotation to surface of defective bone to create an augment volume between the constraint defect points and edge of the shell component.

[0061] Preferably, said step of defining the augment component to fill the defective bone, thereby constraint defect points are offset from the surface of defective bone in a range of compensation.

[0062] Preferably, said step of defining the augment component to fill the defective bone, thereby the range of compensation is 0.5 - 2.0 mm.

[0063] Preferably, said step of determining at least two or more screw trajectories for placement of fastening locations on the augmentation component, using a procedure comprises taking into account one or more of the following criteria: (i) achieving an optimal number of non-intersecting drill directions for screw trajectories; (ii) attesting that said screw trajectories are installed through the optimal quality and volume of bone; (iii) Attesting the screw trajectory with optimal length; (iv) preserved surrounding healthy soft tissue; (v) ensuring that screw trajectory is accessible and not obstructed by surrounding tissue.

[0064] Preferably, said step of determining conditions of the bone on each plurality of the separate implant components thereby using the volume ratio between sum of each smaller portion over the largest portion.

[0065] Preferably, said step of separating components are defined criteria by using the nonintersecting fastening locations on the augmentation component. Preferably, said step of separating components are defined criteria by using the conditions of the bone on each plurality of the separate implant components within the volume ratio of 0.4 - 1.0, or more preferably within the volume ratio of 0.6 - 1.0.

[0066] Preferably, said step of separating components are defined by using distribution of mechanical stress that defined from numerical simulation.

[0067] Preferably, said step of defining the connector thereby the received on the first prosthesis implant and sender on the following prosthesis implants.

[0068] Preferably, said the prosthesis implants are made by additive manufacturing.

[0069] In the fourth aspect, an embodiment is a method of designing a prosthesis system. Said method comprises: dividing a virtually preformed acetabular prosthesis through which one or more screw trajectory elongates, into a plurality of virtually preformed modules, said division being constrained by (i) the volumetric proportion of a smaller virtually preformed module to a larger virtually preformed module, (ii) avoidance of the said screw trajectory, and (iii) the mechanical stress distribution on the virtually preformed modules; and configuring a mating interface by which the said modules are to communicate following their separate and appositional fixation along the said screw trajectory to a defective pelvis bone.

[0070] The third and fourth aspects’ separation plane and division of virtually preformed acetabular prosthesis enable the following advantages over the prior-art methods: optimizing the number and placements of the screw trajectories and hence the resulting prosthesis’s stability upon fixation, optimizing the module’s volumetric proportion with respect to the other modules against the patient specific medical needs, and against the resulting modules’ mechanical strength and stability upon fixation.

[0071] More technical advantages of the optional and preferred embodiments will become apparent in the Detailed Description.

[0072] BRIEF DESCRIPTION OF DRAWINGS

[0073] The principle of the present invention and its advantages will become apparent in the following description, taking into consideration the accompanying drawings in which:

[0074] Fig. 1A shows predominantly femur-facing surfaces of two separate modules of an acetabular prosthesis according to an exemplary embodiment (not to scale). Fig. IB shows predominantly pelvis-facing surfaces of two separate modules of an acetabular prosthesis according to an exemplary embodiment (not to scale).

[0075] Fig. 2 A shows a predominantly femur-facing surface in the perspective view of an acetabular prosthesis that has been formed according to an exemplary embodiment (not to scale).

[0076] Fig. 2B shows a predominantly pelvis-facing surface in the perspective view of an acetabular prosthesis that has been formed according to an exemplary embodiment (not to scale).

[0077] Fig. 3 A shows predominantly femur-facing surfaces of two modules of an acetabular prosthesis according to an exemplary embodiment being appositionally fixed to a pelvis bone (not to scale).

[0078] Fig. 3B shows a cross-sectional side view of two modules of an acetabular prosthesis according to an exemplary embodiment being appositionally fixed to a pelvis bone (not to scale).

[0079] Fig. 4 shows predominantly femur- facing surfaces of two modules of an acetabular prosthesis according to a first alternative embodiment being appositionally fixed to a pelvis bone (not to scale).

[0080] Fig. 5 shows predominantly femur- facing surfaces of two modules of an acetabular prosthesis according to a second alternative embodiment being appositionally fixed to a pelvis bone (not to scale).

[0081] Fig. 6 shows predominantly femur- facing surfaces of two modules of an acetabular prosthesis according to a third alternative embodiment being appositionally fixed to a pelvis bone (not to scale).

[0082] Fig. 7 shows predominantly femur- facing surfaces of two modules of an acetabular prosthesis according to a fourth alternative embodiment being appositionally fixed to a pelvis bone (not to scale).

[0083] Fig. 8 shows a conceptual block diagram of a method of designing a prosthesis system according to an exemplary embodiment.

[0084] Fig. 9 shows front and side view images from the method step of determining the shell component’s position and angle according to an exemplary embodiment (not to scale).

[0085] Fig. 10 shows front and side view images from the method step of defining the augmentation component 3400 according to an exemplary embodiment (not to scale). Fig. 11 shows an image from the method step of determining the screw trajectories according to an exemplary embodiment (not to scale).

[0086] Fig. 12A shows an image that is the first option from the method step of generating the separation plane according to an exemplary embodiment, wherein the volume ratio is 0.83 (not to scale).

[0087] Fig. 12B shows an image that is the second option from the method step of generating the separation plane according to an exemplary embodiment, wherein the volume ratio is 0.74 (not to scale).

[0088] Fig. 12C shows an image that is the third option from the method step of generating the separation plane according to an exemplary embodiment, wherein the volume ratio is 0.69 (not to scale).

[0089] Fig. 13A shows the visualized numerical simulation performed to determine the mechanical stress distribution on the virtually preformed modules, the said virtually preformed modules being divided by the first option of the separation plane previously shown in Fig. 12A (not to scale).

[0090] Fig. 13B shows the visualized numerical simulation performed to determine the mechanical stress distribution on the virtually preformed modules, the said virtually preformed modules being divided by the second option of the separation plane previously shown in Fig. 12B (not to scale).

[0091] Fig. 14 shows a conceptual block diagram of a method of designing a prosthesis system according to an alternative embodiment.

[0092] Fig. 15 shows a prosthesis system comprising an acetabular prosthesis and a drilling guide according to the first exemplary embodiment (not to scale).

[0093] Fig. 16 shows a prosthesis system comprising an acetabular prosthesis and a drilling guide according to the second exemplary embodiment (not to scale).

[0094] Fig. 17 shows a prosthesis system comprising an acetabular prosthesis and a drilling guide according to the third exemplary embodiment (not to scale).

[0095] DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0096] It is to be understood that the following detailed description will be directed to embodiments, provided as examples for illustrating the concept of the present invention only. The present invention is in fact not limited to particular embodiments described, as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of this invention will be limited only by the appended claims.

[0097] The detailed description of the invention is divided into various sections only for the reader’s convenience and disclosure found in any section may be combined with that in another section.

[0098] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0099] It must be noted that as used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise.

[0100] The term “about” when used before a numerical designation, e.g., dimensions, time, amount, and such other, including a range, indicates approximations which may vary by ( + ) or ( - ) 10 %, 5 % or 1 %, or any sub-range or sub-value there between.

[0101] “Comprising” or “comprises” is intended to mean that the articles and methods include the recited elements, but not excluding others. “Consisting essentially of’ when used to define articles and methods, shall mean excluding other elements of any essential significance to the combination for the stated purpose. Thus, a device or method consisting essentially of the elements as defined herein would not exclude other materials or steps that do not materially affect the basic and novel characteristic(s) of the claimed invention. “Consisting of’ shall mean excluding more than trace elements of other ingredients and substantial method steps. Embodiments defined by each of these transition terms are within the scope of this invention.

[0102] THE PROSTHESIS SYSTEM

[0103] Acetabular Prosthesis

[0104] According to the concept of the present invention, a prosthesis system, an acetabular prosthesis, and components thereof, may be constructed of any materials that is known to be suitable for the purpose. Examples of the applicable materials include stainless steels and titanium alloys. More particular examples include Ti6A14V and similar alloy formulations.

[0105] Fig. 1A shows predominantly femur-facing surfaces of two separate modules of an acetabular prosthesis according to an exemplary embodiment. Here, the prosthesis system comprises a first module 1100 and a second module 1200 adapted for separate and appositional fixation thereof to a defective pelvis bone (the said fixation will be shown later in Figs. 3A - 7). This perspective predominantly shows the first module’s 1100 shell component’s section 1110 and its femur-facing surface 1114, and predominantly shows the second module’s 1200 shell component’s section 1210 and its femur-facing surface 1214. Much of the first module’s 1100 augmentation component’s section 1120 and the second module’s 1200 augmentation component’s section 1220 is hidden from this perspective yet will become apparent later in Fig. IB.

[0106] In this exemplary embodiment, the first module’s 1100 shell component’s section 1110 comprises the femur-facing surface 1114 that is adapted to effectively promote friction between the shell component (not formed in Fig. 1 A) and a liner (not shown) to be later interposed between the shell component and the prosthetic femoral head (not shown). Preferably, said friction-promoting adaptation is implemented by way of a plurality of grooves 1116, some of them running in parallel while the others running in another direction, thereby forming many intersections of grooves 1116. The grooves 1116 also promote the adhesion between an orthopedic bonding material (e.g., bone cement or medical glue) and the femur-facing surface 1114.

[0107] This exemplary first module 1100 further comprises two apertures 1112 elongating through its shell component’s section 1110. The said apertures 1112 are adapted for insertion of screws (not shown) for fixation to the pelvis bone (not shown).

[0108] This exemplary first module 1100 further comprises a male connector 1310. Here, the male connector 1310 is adapted to be engaged snugly with the second module’s 1200 female connector 1320. This male connector 1310 takes a form of a substantially rounded rectangular protrusion, though this form does not limit the concept of the present invention as will be apparent in the later alternative embodiments.

[0109] Furthermore, this exemplary first module 1100 comprises an extension 1400 through which two apertures 1410 elongate. The extensions 1400 are adapted to rest on the pelvis bone (not shown), thereby providing the acetabular prosthesis (not formed in Fig. 1A) with additional stability in relation to the pelvis bone. In this embodiment, the extensions 1400 also provide additional reference sites upon which the bone’s uneven surface may be registered, increasing the precision of positioning. These extensions 1400 are further adapted to communicate with an external device (not shown), further increasing the precision of positioning. The said apertures 1410 are adapted for insertion of screws (not shown) for fixing the extension 1400 to the pelvis bone. Fig. 1 A further shows the second module’s 1200 shell component’s section 1210 comprising the femur- facing surface 1214 that is adapted to effectively promote friction between the shell component (not formed in Fig. 1A) and a liner (not shown) to be later interposed between the shell component and the prosthetic femoral head (not shown).

[0110] Friction-promoting adaptation is implemented by increasing surface roughness and / or surface texture modification, which includes but is not limited to designing surface texture, polishing, sandblasting, thermal spray, plasma spray, particle blasting, cladding, and / or machining. Preferably, said friction-promoting adaptation is implemented by way of a plurality of grooves 1216, some of them running in parallel while the others running in another direction, thereby forming many intersections of grooves 1216. The grooves 1216 also promote the adhesion between an orthopedic bonding material (e.g., bone cement or medical glue) and the femur-facing surface 1214.

[0111] This exemplary second module 1200 further comprises two apertures 1212 elongating through its shell component’s section 1210. The apertures 1212 are adapted for insertion of screws (not shown) for fixation to the pelvis bone (not shown).

[0112] This exemplary second module 1200 further comprises a female connector 1320. Here, the female connector 1320 is adapted to be engaged snugly with the first module’s 1100 male connector 1310. This female connector 1320 takes a form of a substantially rounded rectangular recess, though this form does not limit the concept of the present invention as will be apparent in the later alternative embodiments.

[0113] Fig. IB shows predominantly pelvis-facing surfaces of two separate modules of an acetabular prosthesis according to an exemplary embodiment. This perspective is substantially opposite to the view previously shown by Fig. 1A, revealing the components hidden in Fig. 1A. Thus, the description directed to the component of the exemplary embodiment that has been described already in connection with Fig. 1 A will be omitted for brevity.

[0114] Here, the first module’s 1100 augmentation component’s section 1120 comprises a pelvisfacing surface 1122, most of the area of which features porosity 1124. Similarly, the second module’s 1200 augmentation component’s section 1220 comprises a pelvis-facing surface 1222, most of the area of which features porosity 1224. And most of the areas of extensions 1400 are also porous. The utility of said porosity 1124, 1224 is multifold. Notably, it reduces the total weight of the prosthesis system and promotes osseointegration. The augmentation component’s section 1120, 1222 may further comprise a navigator feature that acts as a bone landmark that can assist the surgeon to place it correctly and / or communicate with an external navigator device to assist the surgeon in the insertion process.

[0115] In other embodiments, the augmentation component’s section 1120, 1220 may not comprise a pelvis-facing surface 1122, 1222. In those embodiments, the augmentation component’s section 1120, 1220 may be inserted to replace and / or support the pelvis’s lost structure. The said lost structure occurs when the pelvis is discontinued or has to be cut off. Further, the augmentation component’s section 1120, 1220 is not limited to a solid dense portion. Alternatively, the augmentation component’s section 1120, 1220 may be designed with topology structure within to reduce weight while providing enough strength. Unlike the porosity of pelvis-facing surface, the said topology structure is mentioned about augmentation component body.

[0116] The exemplary modules 1100, 1200 according to the above Figs. 1A and IB and their accompanying description are thus adapted for separate and appositional fixation to a pelvis bone. The said manner of fixation will be described later.

[0117] Fig. 2 A shows a predominantly femur-facing surface in the perspective view of an acetabular prosthesis that has been formed according to an exemplary embodiment. Here, the first module 1100 and the second module 1200 communicate by a mating interface 1300, thereby forming an acetabular prosthesis 1000 that is adapted to reconstruct an acetabulum and / or to augment the pelvis bone.

[0118] The modules’ 1100, 1200 disposition corresponds with that would follow their fixation to the pelvis bone. In this way, the shell component (formed by the combination of the two shell component’s sections 1110, 1210) and the augmentation component (formed by the combination of the two augmentation component’s sections 1120, 1220) are disposed such that the augmentation component is substantially interposed between the shell component and the pelvis bone. The detail of the modules’ 1100, 1200 fixation to the pelvis bone will be shown in the later drawings.

[0119] As shown in Fig. 2 A, the exemplary shell component takes the form resembling a substantially symmetrical cup or hemisphere, whereas the exemplary augmentation component’s form is substantially uneven. This is because the exemplary shell component is intended for further engagement with a liner and a prosthetic femoral head, the shape of which being substantially round and smooth. On the other hand, the exemplary augmentation component is intended for further engagement with the patient’s natural pelvis / acetabulum bone, the topology of which being irregular and patient specific. Regardless, the exemplary augmentation component, specifically their sections 1120, 1220), is designed by a method that can provide a suitable anatomical fitness to the said natural bone. Said method will be described further below.

[0120] In this exemplary embodiment, the acetabular prosthesis’s 1000 mating interface 1300 is formed following the snug engagement between the male connector and the female connector (depicted as 1310 and 1320, respectively, in Figs. 1A and IB). Favorably, the said engagement that holds the mating interface 1300 effectively prevents the first module 1100 and the second module 1200 from rotating in relation to each other. Further, the mating interface 1300 is disposed so as to avoid overlapping the acetabular prosthesis’s 1000 center of rotation 1500 in relation to a femoral head (not shown).

[0121] Furthermore, in each of the modules 1100, 1200, the shell component’s section 1110, 1210 and the augmentation component’s section 1120, 1220 are layered substantially along a direction of acetabular support 1600 when the acetabular prosthesis 1000 is formed.

[0122] Fig. 2B shows a predominantly pelvis-facing surface in the perspective view of an acetabular prosthesis that has been formed according to an exemplary embodiment. This perspective is substantially opposite to the view previously shown by Fig. 2A, revealing the components hidden in Fig. 2 A.

[0123] In addition to the previously described components, Fig. 2B shows that the mating interface 1300 and their respective connectors are adapted so as to provide a space 1330 between the first module 1100 and the second module 1200 when the acetabular prosthesis 1200 is formed. Preferably, this exemplary embodiment comprises the space 1330 having the width within 1 - 4 millimeters. It should be noted that the space’s 1330 width is predetermined by controlling the dimensions of the male and female connectors (see Figs. 1A and IB for detail) so that the space 1330 of such predetermined width is formed upon the full engagement of the connectors.

[0124] Fig. 3 A shows predominantly femur-facing surfaces of two modules of an acetabular prosthesis according to an exemplary embodiment being fixed to a pelvis bone. Fig. 3A also illustrates appositional fixation of the modules / acetabular prosthesis to the pelvis bone that is pertinent to the concept of the present invention. Each having embodied both a share of the shell functionality (i.e., the shell component’s sections 1110, 1210) and a share of the augmentation functionality (i.e., the augmentation component’s sections, hidden from this perspective), the first module 1100 and the second module 1200 are shown herein to have been fixed to the pelvis bone 2000. This exemplary fixation is carried out by inserting three screws 1118 through the apertures (hidden from this perspective) of the first module 1100 and three more screws 1218 though the apertures (hidden from this perspective) of the second module 1200 about the patient’s acetabulum 2100, which is part of the pelvis bone 2000.

[0125] The patient specific form / topology of the exemplary augmentation component (previously described in connection with Fig. 2 A) and its sections would provide the surgeon with precise positional references as to the locations of fixation / scr ewing.

[0126] Further, with the predetermined configurations of the male connector 1310 and the female connector 1320, the engagement of the said connectors 1310, 1312 would be enabled by simple manual efforts, thereby defining the outline of the mating interface 1300 and the width of the space 1330 according to the surgical plan.

[0127] In an exemplary operation illustrated by Fig. 3 A, the sequence by which the modules 1100, 1200 are to be separately and appositionally fixed to the pelvis bone is predetermined by the connectors 1310, 1320 and hence the resulting mating interface 1300: Because in the present exemplary embodiment, the male connector 1310 must be received by the female connector 1320 to form the mating interface 1300, it follows that the second module 1200, having the female connector 1320, must be fixed to the acetabulum 2100 before the first module 1100 is. Accordingly, the surgeon must first place the second module 1200 on the acetabulum 2100, referring to the patient specific form of the augmentation component’s section (hidden from this perspective) for the finer detail of positioning, insert and fix the screws 1218 to the respective apertures (hidden from this perspective); then, with respect to the already fixed second module 1200 the surgeon may appositionally place the first module 1100 on the acetabulum 2100, referring to the patient specific form of the augmentation component’s section (hidden from this perspective) for the finer detail of positioning, manually engage the male connector 1310 with the female connector 1320 to form the mating interface 1300, and then insert and fix the screws 1118 to complete the intended separate and appositional fixation of the two modules and to form the acetabular prosthesis 1000 in situ.

[0128] Therefore, it has been demonstrated that the configurations of the exemplary embodiment work synergistically to direct the surgeon to follow the surgical plan with substantially reduced time lost due to hesitation or manual adjustment as well as reduced chance of making errors. To reiterate, the exemplary modules 1100, 1200 being designed for separate and sequential insertion and in-situ appositional fixation upon the patient’s pelvis bone 2000 also allows a deeper access into the patient’s body with smaller incision and less needs for bone reaming, which in turn reduces the operation’s invasiveness and time.

[0129] Fig. 3B shows a cross-sectional side view of two modules of an acetabular prosthesis according to an exemplary embodiment being appositionally fixed to a pelvis bone. In addition to the previously described components and related operations, Fig. 3B clarifies the sequence by which the modules 1100, 1200 are to be separately and appositionally fixed to the pelvis bone: Here, the only correct way to form the mating interface 1300 is by placing and fixing the second module 1200 before doing the same for the first module 1100 in order to be able to engage the male connector 1310 with the female connector 1320 in the way that is shown in Fig. 3B. It is also apparent from Fig. 3B that, when the acetabular prosthesis is 1000 formed in accordance with the concept of the present invention, the shell component (formed by the combination of the two shell component’s sections 1110, 1210) and the augmentation component (formed by the combination of the two augmentation component’s sections 1120, 1220) are disposed such that the augmentation component 1120, 1220 is substantially interposed between the shell component 1110, 1210 and the pelvis bone 2000.

[0130] Further, Fig. 3B depicts the role of the augmentation component’s sections 1120, 1220, particularly the uneven configurations of their respective pelvis-facing surfaces 1122, 1222, in providing the surgeon with positional references when placing the respective modules 1100, 1200 on the acetabulum 2100 of the pelvis bone 2000.

[0131] Next, alternative embodiments will be discussed to further illustrate the concept of the present invention.

[0132] In alternative embodiments shown in Figs. 4 - 6, the male connectors 1310 and the female connectors 1320 are configured so as to take the forms of substantially rectangular recess and protrusion (Fig. 4), substantially semicircular protrusion and recess (Fig. 5), and substantially rounded-corner triangular protrusion and recess (Fig. 6), respectively.

[0133] Specifically, Fig. 4 illustrates that the sequence by which the modules 1100, 1200 are to be appositionally fixed to the pelvis bone 2000 or the acetabulum 2100 may be predetermined differently from that shown previously in Figs. 3A, 3B. With the male connector being connected to the second module 1200, the alternative embodiment according to Fig. 4 demands the surgeon to place and fix the first module 1100 to the acetabulum 2100 before placing and fixing the second module 1200 to the same.

[0134] Further, the alternative embodiment according to Fig. 7 comprises two additional screws 1340 being applied through the male connector 1310 and the underlying female connector 1320 and then to the further underlying bone. In this way, the connectors 1310, 1320 are adapted for extra mechanical sealing. Other applicable mechanical sealing means include tolerance fitting, pinholes, standalone or combination of sealing mechanisms such as step-locking, pin-holes, snap-fit, hinge lock, dowel joints, mortis e&tenon, twin mortise&tenon, T-halving joint, Dovetail halving joint, tongue&groove joint, biscuit joint, shouldered dovetail, double jigsaw joint, double dovetail, triple dovetail symmetrical double dovetail, shoulder triple dovetail, ginkgo scarf with stub tenons, three body locking pin, and screw.

[0135] Moreover, chemical sealing is within the purview of the present invention, examples of the said chemical sealing include polymethyl methacrylate (PMMA) and medical glues. When such a chemical sealing is used, the male connector 1310 and the female connector 1320 may be preferably configured so that the resulting mating interface 1300 to promote adherence and / or retention of the said sealing.

[0136] The components or parts of the acetabular prosthesis to which the above-described mechanical and chemical sealings may apply according to the present invention are not limited to the connectors.

[0137] Surgical Guide

[0138] A prosthesis system according to an embodiment may further comprise a surgical guide. The following exemplary embodiments will be directed to those wherein the surgical guides are drilling guides.

[0139] Fig. 15 shows a prosthesis system comprising an acetabular prosthesis and a drilling guide according to the first exemplary embodiment. Here, the embodiment is shown in a state where the acetabular prosthesis 1000 has been formed of a plurality of modules (hidden from this perspective) communicating by the mating interface (hidden from this perspective) and placed on the pelvis bone 2000. The said acetabular prosthesis 1000 is to be fixed to the pelvis bone 200 according to the previously provided description. On the acetabular prosthesis 1000 the drilling guide 5000 is set to assist the said fixation. In this embodiment, the drilling guide 5000 takes the form of a single-piece drilling guide, but a drilling guide according to the present invention is not necessary a single-piece; medical circumstances may favor a drilling guide designed to be formed by assembling a plurality of modules. Further, this first exemplary drilling guide 5000 is constructed of a suitable plastic resin and comprises the main base 5100 and a plurality of screw barrels 5200.

[0140] The main base 5100 further comprises the free surface 5110, the engaging surface 5120, and the edge 5130. In this embodiment, the free surface 5110 is not intended for contact with a bone or other system's components, and thus is substantially smooth. Fig. 15 predominantly shows the free surface 5110 and hides the engaging surface 5120 on the opposing side of the main base 5100. The engaging surface 5120 contacts the acetabular prosthesis 1000 and thus is adapted to have a shape and topography that corresponds to the shape and topography of the acetabular prosthesis’s 1000 contacting surface, which in this embodiment is the shell component’s femur-facing surface (hidden from this perspective; refer to the drawing reference Nos. 1114, 1124 shown in Figs. 2A, 3A, and 4 - 7). Such shape and topography favorably promote friction as well as provide the registration sites which in turn promote precise alignment between the acetabular prosthesis 1000 and the drilling guide 5000. The exemplary edge 5130 defines the main base 5100, favorably so that the main base 5100 may be set on the acetabular prosthesis 1000 with the former being snugly enclosed by the latter. This manner of setting promotes a tight fitness there-between which effectively secures the favorable alignment of the screw barrel 5200.

[0141] Each screw barrel 5200 further comprises a substantially cylindrical ridge 5210 and a substantially cylindrical channel 5220. The ridge 5210 protrudes from the main base 5100 and defines the channel 5220. The channel 5220 elongates through the ridge 5210 and through the underlying main base 5100. The direction along which the channel 5220 elongates corresponds to the elongation of the acetabular prosthesis’s 1000 aperture (hidden from this perspective; refer to the drawing reference Nos. 1112, 1212 shown in Fig. 2A). As previously noted, a screw (not shown) is to be inserted though the said acetabular prosthesis’s 1000 aperture to provide the latter with a fixation to the pelvis bone 2000. As such, the said configuration of the ridge 5210 and the channel 5220 limits the screw’s tilting and thus guides the drilling of the screw along a suitable angle into the pelvis bone 2000. The screw barrel’s 5200 number, positions, and angles correspond to those features of the apertures of the underlying acetabular prosthesis 1000. With this, the importance of precise alignment and secure engagement enabled by the configuration of the engaging surface 5120 and by the edge 5130 has become apparent.

[0142] Further, Fig. 16 shows a prosthesis system comprising an acetabular prosthesis and a drilling guide according to the second exemplary embodiment. In addition to the components, their nature and functional relationships which have been shown and described previously in connection with Fig. 15, the drilling guide 5000 according to this second exemplary embodiment comprises an extended base 5300, constructed of the same material as and integrally to the main base 5100. The extended base 5300 further comprises a free surface 5310, an engaging surface 5320, and an edge 5330.

[0143] In this embodiment, the free surface 5310 is not intended for contact with a bone or other system's components, and thus is substantially smooth. Fig. 16 predominantly shows the free surface 5310 and hides the engaging surface 5320 on the opposing side of the extended base 5300. The engaging surface 5320 contacts the acetabular prosthesis 1000 and thus is adapted to have a shape and topography that corresponds to the shape and topography of the acetabular prosthesis’s 1000 contacting surface, which in this embodiment is the augmentation component’s pelvis-facing surface (hidden from this perspective; refer to the drawing reference Nos. 1122, 1222 shown in Figs. 2A - 3A). Such shape and topography favorably promote friction as well as provide the registration sites which in turn promote precise alignment between the acetabular prosthesis 1000 and the drilling guide 5000. The exemplary edge 5330 defines the extended base 5300, favorably so that the extended base 5300 may be set on the acetabular prosthesis 1000 with the latter being snugly enclosed by the former. Favorably, due to the precisely designed edges 5130, 5330, Fig. 16 shows the main base 5100 and the extended base 5300 clasping the acetabular prosthesis’s 1000 substantial portion, thereby providing it with even more secure engagement with the drilling guide 5000.

[0144] Fig. 17 shows a prosthesis system comprising an acetabular prosthesis and a drilling guide according to the third exemplary embodiment. In addition to the components, their nature and functional relationships which have been shown and described previously in connection with Figs. 15 - 16, the drilling guide 5000 according to this third exemplary embodiment comprises a plurality of jackets 5400. Each of the said exemplary jacket 5400 is constructed of a titanium-based alloy and further comprises a flat cap 5410 and a hollow sleeve 5420 of which inner diameter defines a screw chamber 5430.

[0145] The jacket’s 5400 sleeve 5420 is inserted through the screw barrel’s 5200 channel 5220, and its cap 5410 rests upon the ridge 5210. Each of the jackets 5400 may be fixed to or removable from the screw barrel 5200 depending on the circumstantial needs or preferences. Accordingly, it is preferred that the sleeve’s 5420 length is not greater than that of the channel 5220. The screw chamber 5430, though which a screw may be inserted and reach the designated part of the pelvis bone (not shown), elongates through the sleeve 5420. The screw chamber’s 5430 diameter is smaller than that of the screw barrel’s 5200 channel, providing an even greater limitation to the screw’s tilting and thus guiding the screw along a more precise drilling direction. Furthermore, the jacket 5400, being made of a mechanically stronger and more heat-resistant material, protects the screw barrel 5200 from wear and heat arising from the drilling action.

[0146] THE DESIGNING METHOD OF PROSTHESIS SYSTEM

[0147] The following exemplary and alternative embodiments of the designing method of prosthesis system are preferably computer-aided or computer-implemented.

[0148] Fig. 8 shows a conceptual block diagram of a method of designing a prosthesis system according to an exemplary embodiment. The exemplary designing method 3000 comprises steps of obtaining medical images 3100, determining the defective bone 3200, determining the shell component’s position and angle 3300, defining the augmentation component 3400, determining the screw trajectories 3500, generating the separation plane 3600, and then configuring the mating interface 3700. Here, the foregoing method steps are shown to be ordered from 3100, 3200, 3300, 3400, 3500, 3600, and then 3700. This exemplary ordering does not limit the scope of the present invention. Depending on the circumstances, those steps may be reordered, some steps may be carried out concurrently, and / or more steps may be added before, after, or between any of the steps shown in Fig. 8. The following description shall cause the skilled person to appreciate the present inventive concept and thus enable them to make those minor adjustments. And the later drawings / description will illustrate alternative examples in which the method steps are adjusted.

[0149] The step of obtaining medical images 3100 may be carried out by any known technique in the relevant arts, particularly including the known diagnostic radiology technique, and more particularly including X-ray fluoroscopy, computed tomography (CT) and magnetic resonance imaging (MRI). Favorably, the employed technique should produce medical images conducive to computerized processing. In the exemplary embodiment, the medical images are obtained by computed tomography (CT) scan technique, and the said medical images include those obtained from the patient’s healthy bone on the opposite side of pelvis / acetabulum.

[0150] The step of determining the defective bone 3200 refers to the processing of the medical images obtained from 3100 to generate a three-dimensional image of the pelvis bone defect that is complete of sufficient for determining the patient-specific natures of anatomical references and the bone defects sustained by the patient. Known image processing techniques may be used to generate such an image.

[0151] As previously noted, an exemplary shell component takes the form resembling a substantially symmetrical cup or hemisphere. As such, the exemplary step of determining the shell component’s position and angle 3300 is carried out to align the said cup / hemisphere corresponding to the center of rotation on the other side of the femoral head. In this exemplary determination of the shell component’s position and angle 3300, the three-dimensional image of the healthy bone is also generated and mirrored for the reference of the said center of rotation, position, and angle. Further, said exemplary step 3300 favorably makes the said cup / hemisphere to arrange the angle of the shell component in 30 - 50 degrees abduction and 5 - 25 degrees anteversion.

[0152] Fig. 9 shows front and side view images from the method step of determining the shell component’s position and angle 3300 according to an exemplary embodiment. Here, the preformed shell component 3310 is virtually generated with reference to the mirrored image of the patient’s healthy pelvis bone. The preformed shell component’s 3310 thickness is preferably substantially uniform and may be determined according to the known arts. Said preformed shell component 3310 is virtually inserted into the defective pelvis bone’s 3320 acetabulum 3330. The volume enclosed by the preformed shell component 3310, of which position and angle have been determined thus, is considered the volume of defect 3340. It should be noted that when the shell component 3310 is virtually inserted thus, the void between the edge of the preformed shell component 3310 and the edge of the acetabulum 3330 is considered the volume of augmentation 3350 which is to be addressed in another method step to be discussed in the next paragraphs.

[0153] Optionally, the step of determining the shell component’s position and angle 3300 may be followed (but not necessarily in a direct succession) by configuring the shell component’s surface properties. This optional step includes, where appropriate and preferred, adapting the shell component’s femur-facing surface to effectively promote friction between the shell component and a liner or the prosthetic femoral head. Exemplary results of the said adaptation include the grooves as shown and described previously in connection with Fig. 1A.

[0154] Next, the exemplary step of defining the augmentation component 3400 is carried out to fill the defective bone, thereby making a constraint defect points from the predetermined center of rotation to surface of defective bone to create an augment volume between the constraint defect points and edge of the shell component. This exemplary step of defining the augmentation component 3400 also favorably resulted in constraint defect points being offset from the surface of defective bone in a range of compensation. Moreover, according to this exemplary step, the range of compensation is favorably within 0.5 - 2.0 mm.

[0155] Fig. 10 shows front and side view images from the method step of defining the augmentation component 3400 according to an exemplary embodiment. The main purpose of this method step is to virtually define the outlines of the preformed augmentation component 3410 based upon the volume of augmentation (indicated in Fig. 9 as reference No. 3350; hidden from Fig. 10’s perspective). Here, a plurality of constraint defect points 3420 are determined by ray that is virtually created from previous center of rotation combine with point around the edge of the preformed shell component’s outer diameter to constraint and set the implant boundary. The constraint defect points 3420 are in turn used to determine the volume of the preformed augmentation component 3410.

[0156] Optionally, the step of defining the augmentation component 3400 may be followed (but not necessarily in a direct succession) by configuring the augmentation component’s surface properties. This optional step includes, where appropriate and preferred, adapting the augmentation component’s pelvis-facing surface to feature porosity. Exemplary results of the said adaptation have been shown and described previously in connection with Fig. IB.

[0157] Further, in the exemplary step of determining the screw trajectories 3500, at least two or more screw trajectories for placement of fastening locations on the augmentation component, using a procedure comprises taking into account one or more of the following criteria: achieving an optimal number of non-intersecting drill directions for screw trajectories; attesting that said screw trajectories are installed through the optimal quality and volume of bone; attesting the screw trajectory with optimal length; (iv) preserved surrounding healthy soft tissue; and (v) ensuring that screw trajectory is accessible and not obstructed by surrounding tissue.

[0158] Fig. 11 shows a schematic image from the method step of determining the screw trajectories 3500 according to an exemplary embodiment. Here, the screw trajectories 3510 along which a plurality of screws 3520 are virtually inserted, are virtually determined in their positional and angular placements upon the preformed acetabular prosthesis 3530 for its intended fixation upon the pelvis bone’s 3540 acetabulum 3550.

[0159] According to the exemplary embodiment, the screw trajectories 3510 are determined according to the patient specific medical / mechanical needs to fix the preformed acetabular prosthesis 3530 upon the pelvis bone’s 3540 acetabulum 3550. As such, the course of the screw trajectories 3510 is irrespective of whether the said trajectories are to elongate through the prosthesis’s shell component or augmentation component or both. Regardless, there is one important constraint: the course of the screw trajectories 3510 should preferably avoid the separation plane to prevent structural weakness. The relationship between the screw trajectories 3510 and the separation plane will be described later.

[0160] The screw trajectories 3510 are important to load distribute to the axial bone (spine) and maintain the stability of the acetabular augmentation. Favorable positions of the screws 3520 include: posterior ilium, a large fan bone having high bone volume. Sometimes the screw 3520 can point into SI joint; anterior ilium, similarly, this direction is recommended for good load distribution from femur expanding to the opposite direction and hence the better stability; the ischium bone, which makes the screw 3520 expand like a triangle, creating the pinch effect on to the implant; and the pubis bone which despite having a small bone area would further promote the even load distribution.

[0161] In the exemplary step of generating the separation plane 3600, the separation plane refers to an imaginary plane by which the virtually preformed acetabular prosthesis according to the concept of the present invention is divided into a plurality of virtually preformed modules. The said separation plane also corresponds to the outline of the mating interface by which the modules communicate and form the acetabular prosthesis when fixed to the patient’s pelvis bone. In this exemplary embodiment, the separating components are favorably defined criteria by using the nonintersecting fastening locations on the augmentation component, by using the conditions of the bone on each plurality of the separate implant components within the volume ratio, and by using distribution of mechanical stress that defined from numerical simulation. Although it is within the purview of the present inventive concept to generate more than one separation plane or to design an acetabular prosthesis comprising more than two modules, for brevity, the description regarding the exemplary embodiment is directed to implementation of the method to generate one separation plane and to design an acetabular prosthesis comprising two modules.

[0162] Preferably, the separation planes are generated at the center of rotation. The said planes may be generated to be superior-inferior tilted or medial-lateral tilted. Regardless, the separation plane can be a combination of many planes in any direction as far as they separate the virtually preformed modules according to the volume ratio falling within the acceptable range.

[0163] But the preferably still the same, the separation plane that pass through center.

[0164] According to the exemplary embodiment, the separation plane’s performance is measurable by the volume ratio by which the virtually preformed acetabular prosthesis is divided by the said plane into the virtually preformed modules. Following such division, the volume ratio refers to the volumetric proportion of the smaller virtually preformed module to the larger virtually preformed module. This means halving the virtually preformed acetabular prosthesis into two volumetrically equivalent virtually preformed modules would result in the volume ratio of 1.0. The volume ratio of 1.0 is ideal if the reduction of invasiveness alone is the design objective — an unlikely occurrence in practice. The causes by which the volume ratio may deviate from 1.0 include, notably, the patientspecific conditions of the bone. A larger module affords a greater mechanical support to a structurally weaker part of the acetabulum / pelvis bone. Said structural weakness is caused by the conditions of the bone. And the conditions of the bone may be affected by that part of the bone’s natural state, or by the defects sustained by that part of the bone. Therefore, a separation plane is preferably generated so that a larger module positionally corresponds to a weaker or more damaged part of the pelvis / acetabulum to be reconstructed, and a smaller module positionally to a stronger or less damaged part thereof, so long as the resulting volume ratio falls within an acceptable or favorable range. In the exemplary embodiment, the volume ratio falls within the favorable range of 0.4 - 1.0 and falls within the more favorable range of 0.6 - 1.0.

[0165] Further, in the exemplary embodiment, the volume ratio is one of the preferable three constraints for the present method step 3600. The three constraints are: the volume ratio, that the separation plane must not intersect the screw trajectories, and that the distribution of mechanical stress must be acceptable. It is within the purview of the present inventive concept that more than one separation plane may be generated. In such case, only one separation plane is selected in accordance with the plane’s performance under the above mentioned three constraints.

[0166] Fig. 12A - C show an example of such a scenario, wherein based upon the same screw trajectories 3610, each the virtually preformed acetabular prosthesis 3620 is divided by the separation plane 3630 into a larger module 3622 and a smaller module 3624. Fig. 12A depicts the first optional division whereby the volume ratio (R) becomes 0.83. Fig. 12B depicts the second optional division whereby the volume ratio (R) becomes 0.74. And Fig. 12C depicts the third optional division whereby the volume ratio (R) becomes 0.69. All said three options have passed the abovementioned three preferable constraints and thus are available for selection. Notably, in all those options, the separation planes 3630 are tilted towards the acetabulum’s 3640 superior direction 3642, causing the larger module 3622 to correspond to the acetabulum’s 3640 inferior direction 3644 and the smaller module 3624 to correspond to the superior direction 3642. The degrees of said superior-tilting increase inversely to the volume ratio, becoming the most manifest when R = 0.69 in Fig. 12C. In other words, in accordance with the concept of the preferred embodiment, the patientspecific bone conditions dictate that the larger module 3622 must always be disposed on the inferior direction 3644. It should be further noted that in Fig. 12A, the separation plane 3630 is also tilted towards the medial direction 3646 to achieve R = 0.83 while satisfying the other two constraints.

[0167] Regarding the selection, although the separation plane 3630 as depicted in Fig. 12A yields a more favorable volume ratio (R = 0.83), the said separation plane 3630 is disposed so close to one of the screw trajectories 3610 that it exposes an acetabular prosthesis fabricated from this option to an unfavorably high mechanical stress in the area surrounding the screw trajectory 3610, and hence the failure thereof. That problematic screw trajectory 3610 is marked with an X on Fig. 12A. The subsequent Fig. 13A shows a visualized numerical simulation which indicates the said unfavorable high mechanical stress area 3612. Further, because according to the numerical simulation visualized in Fig. 13B, the modules 3622, 3624 divided by the separation plane 3630 in Fig. 12B are free of a high mechanical stress area 3612 while achieving a volume ratio (R = 0.74) that is favorably greater than that achieved by the option of Fig. 12C (R = 0.69). Accordingly, the separation plane 3630 as depicted in Fig. 12B is selected over the other two options arising from the exemplary embodiment. In the foregoing exemplary embodiment, the said numerical simulation is favorably based upon the finite element analysis (FEA) technique.

[0168] Next, in the exemplary step of configuring the mating interface 3700, the received on the first prosthesis implant and sender on the following prosthesis implants. In this step, virtually preformed acetabular prosthesis’s modules are virtually provided with connectors for forming the mating interface. The virtual connectors and their resulting virtual mating interfaces may take any form, including but not limited to those previously shown in Figs. 3A and 4 - 7. Preferably, the connectors take the rounded rectangular form, i.e., the male connector being a round rectangular protrusion and the female connector being a rounded rectangular recess: The rectangular outline is particularly suitable for preventing the connected modules from rotating in relation to each other, while the rounded edges are conducive to the insertion into the patient’s body.

[0169] The connectors and the resulting mating interface may be further configured according to the predetermined sequence by which the modules are to be appositionally fixed to the pelvis bone. The said sequence is preferably predetermined based upon the patient-specific conditions of the bone: a structurally weaker or more damaged part of the bone should correspond to a module of an earlier fixation in the sequence. Taking into consideration a previously mentioned preference that a volumetrically larger module should correspond to a structurally weaker or more damage part of the bone, then it is even more preferable to determine so that to a pelvis bone a larger module is to be fixed before a smaller module.

[0170] The connectors and the resulting mating interface may also be further configured according to the space between the module to be provided by the mating interface following the formation of the acetabular prosthesis. In this exemplary embodiment, the said configuration is effective for providing the said space having a width within the favorable range of 1 - 4 millimeters.

[0171] Furthermore, Fig. 14 shows a conceptual block diagram of a method of designing a prosthesis system according to an alternative embodiment. In addition to the method steps previously shown and described according to Figs. 8 - 13B above, this alternative embodiment comprises more steps of configuring the extension(s) 3800 and reviewing the design 3900.

[0172] In this alternative embodiment, the step of configuring the extension(s) 3800 is carried out. Said extension(s) is to rest on the pelvis bone to provide the resulting acetabular prosthesis with additional stability in relation to the pelvis bone. This step 3800 includes determining the extension’ s number (if any), position, angle, number, position of the aperture(s) for insertion of screws, and allocation thereof on the plurality of modules. Optionally, this step 3800 may be followed (but not necessarily in a direct succession) by configuring the extension’s surface properties. This optional step includes, where appropriate and preferred, adapting the extension’s surface to feature porosity. Exemplary results of the said adaptation have been shown and described previously in connection with Fig. IB.

[0173] If following the review 3900 the design is approved, then the method proceeds to fabricating the prosthesis system 4000; if, on the other hand, following the review 3900 the design is rejected, then the method loops back to an earlier step. In this alternative embodiment, the loop may entail a redirection to the start of either the step of determining the shell component’s position and angle 3300 or the step of determining the screw trajectories 3500, depending on the corrective instructions which upon the rejection has been indicated by the reviewer (which may be a human reviewer, such as a surgeon or medical technician, or a computerized reviewer, such as an artificial-intelligence machine). Again, the foregoing destinations of the loop-back are examples based upon the present inventors’ assessment that the shell component’s position and angle or the screw trajectories correlate to the difficulty of implantation and so are among the likeliest causes for the rejection; they do not limit other destinations from being included or assigned in their stead.

[0174] The resulting designs of prosthesis system are conducive to the fabrication in the respective step 4000 by any known suitable technique of additive manufacturing.

[0175] List of Drawing References

[0176] 1000 Acetabular prosthesis

[0177] 1100 First module

[0178] 1110 Shell component’ s section

[0179] 1112 Aperture

[0180] 1114 F emur-facing surface

[0181] 1116 Groove

[0182] 1118 Screw

[0183] 1120 Augmentation component’s section

[0184] 1122 Pelvis-facing surface

[0185] 1124 Porosity 1200 Second module

[0186] 1210 Shell component’ s section

[0187] 1212 Aperture

[0188] 1214 Femur-facing surface

[0189] 1216 Groove

[0190] 1218 Screw

[0191] 1220 Augmentation component’s section

[0192] 1222 Pelvis-facing surface

[0193] 1224 Porosity

[0194] 1300 Mating interface

[0195] 1310 Male connector

[0196] 1320 Female connector

[0197] 1330 Space

[0198] 1340 Screw

[0199] 1400 Extension

[0200] 1410 Aperture

[0201] 1500 Center of rotation

[0202] 1600 Direction of acetabular support

[0203] 2000 Pelvis bone

[0204] 2100 Acetabulum

[0205] 3000 The designing method

[0206] 3100 Obtaining medical images

[0207] 3200 Determining the defective bone

[0208] 3300 Determining the shell component’s position and angle

[0209] 3310 Preformed shell component

[0210] 3320 Pelvis bone

[0211] 3330 Acetabulum

[0212] 3340 Volume of defect

[0213] 3350 Volume of augmentation

[0214] 3400 Defining the augmentation component 3410 Preformed augmentation component

[0215] 3420 Constraint defect points

[0216] 3500 Determining the screw traj ectories

[0217] 3510 Screw trajectory

[0218] 3520 Screw

[0219] 3530 Preformed acetabular prosthesis

[0220] 3540 Pelvis bone

[0221] 3550 Acetabulum

[0222] 3600 Generating the separation plane

[0223] 3610 S crew traj ectory

[0224] 3612 High mechanical stress area

[0225] 3620 Preformed acetabular prosthesis

[0226] 3622 Larger module

[0227] 3624 Smaller module

[0228] 3630 Separation plane

[0229] 3640 Acetabulum

[0230] 3642 Superior direction

[0231] 3644 Inferior direction

[0232] 3646 Medial direction

[0233] 3648 Lateral direction

[0234] 3700 Configuring the mating interface

[0235] 3800 Configuring the extension

[0236] 3900 Reviewing the design

[0237] 4000 Fabricating the prosthesis system

[0238] 5000 Drilling guide

[0239] 5100 Main base

[0240] 5110 Free surface

[0241] 5120 Engaging surface

[0242] 5130 Edge

[0243] 5200 Screw barrel 5210 Ridge

[0244] 5220 Channel

[0245] 5300 Extended base

[0246] 5310 Free surface

[0247] 5320 Engaging surface

[0248] 5330 Edge

[0249] 5400 Jacket

[0250] 5410 Cap

[0251] 5420 Sleeve

[0252] 5430 Screw chamber

Claims

CLAIMS1. A prosthesis system, comprising a plurality of modules, each of said modules being adapted for separate and appositional fixation thereof to a defective pelvis bone, such that when all the modules have been fixed to the pelvis bone, the modules communicate by a mating interface, thereby forming an acetabular prosthesis that is adapted to reconstruct an acetabulum and / or to augment the pelvis bone.

2. The prosthesis system of claim 1, wherein the mating interface is further adapted correspondingly to a predetermined sequence by which the modules are to be appositional fixed to the pelvis bone.

3. The prosthesis system of claim 1, wherein the mating interface is disposed so as to avoid overlapping the acetabular prosthesis’ center of rotation in relation to a femoral head.

4. The prosthesis system of claim 1, wherein the mating interface is adapted so as to provide a space between the modules when the acetabular prosthesis is formed.

5. The prosthesis system of claim 1, wherein the acetabular prosthesis further comprises an extension to rest on the pelvis bone, thereby providing the acetabular prosthesis with additional stability in relation to the pelvis bone.

6. The prosthesis system of claim 1, further comprising an assisted surgical guide for placement on said a modular augmented system, said the assisted surgical guide comprising implant-facing surface and one or more trajectory guiding element corresponding with predetermined fixation trajectory and partially made from a first material.

7. The prosthesis system of claim 6, comprising the said assisted surgical guide, wherein implantfacing surface corresponding at least partially of shell component and / or augmentation component.

8. The prosthesis system of any claim of claims 6 - 7, comprising the assisted surgical guide wherein said implant-facing surface form an extension to correspond with extension of modular augmented system.

9. The prosthesis system of any claim of claims 6 - 8, comprising the assisted surgical guide wherein said assisted surgical guide further comprising guide member which partially made from a second material that harder than first material.

10. A prosthesis system, comprising a plurality of modules, each of said modules comprising:(i) a shell component’s section;(ii) an augmentation component’s section; and(iii) a connector by which the plurality of modules may communicate, thereby forming an acetabular prosthesis comprising a shell component and an augmentation component, wherein — the modules are adapted for separate and appositional fixation to a pelvis bone, and when the acetabular prosthesis is formed, the shell component and the augmentation component are disposed such that the augmentation component is substantially interposed between the shell component and the pelvis bone.

11. The prosthesis system of claim 10, wherein in each of the modules, the shell component’ s section and the augmentation component’s section are layered substantially along a direction of acetabular support when the acetabular prosthesis is formed.

12. The prosthesis system of claim 10, wherein the connector is further adapted correspondingly to a predetermined sequence by which the modules are to be appositionally fixed to the pelvis bone.

13. The prosthesis system of claim 10, wherein the connector is adapted so as to provide a space between the modules when the acetabular prosthesis is formed.

14. The prosthesis system of claim 10, wherein the connector is adapted for mechanical or chemical sealing.

15. The prosthesis system of claim 10, wherein the acetabular prosthesis comprises an extension to rest on the pelvis bone, thereby providing the acetabular prosthesis with additional stability in relation to the pelvis bone.

16. The prosthesis system of claim 15, wherein the extension is porous.

17. The prosthesis system of claim 10, wherein the shell component or the augmentation component comprises a pelvis-facing surface that is porous.

18. The prosthesis system of claim 10, further comprising an assisted surgical guide for placement on said a modular augmented system, said the assisted surgical guide comprising implant-facing surface and one or more trajectory guiding element corresponding with predetermined fixation trajectory.

19. A assisted surgical guide of claim 18, wherein said implant-facing surface corresponding at least partially of shell component and / or augmentation component.

20. A assisted surgical guide of any claim of claims 18 - 19, wherein said implant-facing surface form an extension to correspond with extension of modular augmented system.

21. A assisted surgical guide of any claim of claims 18 - 20, wherein said assisted surgical further comprising guide member which partially made from material that harder than said assisted surgical.

22. A method of making the prosthesis system, said system comprising a step of(a) Determining the defective bone from medical images.(b) Determining the shell component’s position and angle.(c) Defining the augment component to fill the defective bone(d) Determining the screw trajectories for fastening the prosthesis.(e) Generating the separation plane to separate a prosthesis into plurality of modules conducive to separate implantation, each of the modules comprising a shell component’s section, an augmentation component’s section, and a connector with which the plurality of modules communicates, thereby forming a shell component and an augmentation component which are disposed so as to share a substantially common center, said method comprising configuring the connector based upon the following parameters:(i) placement of fastening locations on the prosthesis,(ii) conditions of the bone on each plurality of the separate implant components.(iii) distribution of mechanical stress.

23. The method of making the prosthesis system of claim 22 wherein said step of determining the shell component’s position from medical images, thereby making the hemisphere correspond to the center of rotation on the other side of the femoral head.

24. The method of making the prosthesis system of any claim of claims 22 - 23 wherein said step of determining the shell component’s position from medical images, thereby making hemisphere to arrange an angle of the shell component 30 - 50 degrees abduction and 5 - 25 degrees anteversion.

25. The method of making the prosthesis system of any claim of claims 22 - 24 wherein said step of defining the augment component to fill the defective bone, thereby making a constraint defect points from the predetermined center of rotation to surface of defective bone to create an augment volume between the constraint defect points and edge of the shell component.

26. The method of making the prosthesis system of any claim of claims 22 - 25 wherein said step of defining the augment component to fill the defective bone, thereby constraint defect points are offset from the surface of defective bone in a range of compensation.

27. The method of making the prosthesis system of any claim of claims 22 - 26 wherein said step of determining at least two or more screw trajectories for placement of fastening locations on the augmentation component, using a procedure comprises taking into account one or more of the following criteria:(i) Achieving an optimal number of non-intersecting drill directions for screw trajectories;(ii) Attesting that said screw trajectories are installed through the optimal quality and volume of bone.(iii) Attesting the screw trajectory with optimal length.(iv) preserved surrounding healthy soft tissue.(v) ensuring that screw trajectory is accessible and not obstructed by surrounding tissue.

28. The method of making the prosthesis system of any claim of claims 22 - 27 wherein said step of determining conditions of the bone on each plurality of the separate implant components thereby using the volume ratio between sum of each smaller portion over the largest portion.

29. The method of making the prosthesis system of any claim of claims 22 - 28 wherein said step of separating components are defined criteria by using the non-intersecting fastening locations on the augmentation component.

30. The method of making the prosthesis system of any claim of claims 22 - 29 wherein said step of separating components are defined criteria by using the conditions of the bone on each plurality of the separate implant components within the volume ratio of 0.4 - 1.0.

31. The method of making the prosthesis system of any claim of claims 22 - 30 wherein said step of defining the connector thereby the received on the first prosthesis implant and sender on the following prosthesis implants.

32. A method of designing a prosthesis system, said method comprising: dividing a virtually preformed acetabular prosthesis through which one or more screw trajectory elongates, into a plurality of virtually preformed modules, said division being constrained by (i) the volumetric proportion of a smaller virtually preformed module to a larger virtually preformed module, (ii) avoidance of the said screw trajectory, and (iii) the mechanical stress distribution on the virtually preformed modules; and configuring a mating interface by which the said modules are to communicate following their separate and appositional fixation along the said screw trajectory to a defective pelvis bone.

Images