Method for selecting a femoral prosthesis corresponding to the patient s morphotype in a system of families of prostheses

Abstract

A computer-executable method for selecting a femoral prosthesis (1) is carried out by acquiring a 3D model of a patient's femur at a pre-operative stage. A plurality of identification parameters identifying the structure of the femoral bone are measured / acquired on that model. These parameters are used to query a database with the aim of identifying within it the prosthesis (1) that best approximates the structure of the femur. Based on a correspondence between the measured parameters and the ones present within the database, the femoral prosthesis (1) having the highest number of matches is selected. Also proposed is an arthroplasty system comprising a plurality of prostheses (1) subdivided into families according to respective identification parameters enabling the identification of the specific prosthesis (1) that best satisfies and adapts to the needs and morphotype of the patient.

Description

[0001] “METHOD FOR SELECTING A FEMORAL PROSTHESIS CORRESPONDING TO THE PATIENT’S MORPHOTYPE IN A SYSTEM OF FAMILIES OF PROSTHESES”

[0002] DESCRIPTION

[0003] The present invention relates to the technical field of medical devices, in particular prostheses, and methods for identifying and selecting them.

[0004] In particular, the present invention relates to a method for selecting a femoral prosthesis, as well as a knee arthroplasty system capable of optimising the processes of identifying and selecting a specific prosthesis based on operating needs.

[0005] In the setting of a bone reconstruction operation, it is necessary to perform a series of cuts on the bone to enable the subsequent insertion and coupling of a prosthesis replicating the shape of the damaged bone structure requiring replacement.

[0006] In order to be able to reduce the patient’s discomfort to a minimum and optimise the postoperative recovery and rehabilitation process, it is customary to carry out a design process whereby a special customised prosthesis, specifically modelled on the basis of measurements of the patient’s bone, as well as the geometry of the specific cuts to be performed during the operation, is generated for the individual patient.

[0007] This approach is particularly followed in the context of knee reconstruction operations, which can be carried out, for example, according to the kinematic alignment (KA) approach.

[0008] In accordance with this technique, the objective is to reconstruct the specific alignment of the patient’s limbs, as well as to completely restore his or her biomechanical situation on the basis of the specific kinematic axes of the patient him / herself.

[0009] By way of example, in the case of a patient affected by arthritis, it is possible to perform a femur arthroplasty operation by resecting the bone along cutting axes specifically selected on the basis of the patient’s pre- arthritic kinematic axes.

[0010] In this context, it appears to be particularly advantageous to produce a customised prosthesis in order to be able to obtain a replica as faithful as possible of the preoperative joint situation.

[0011] However, it is evident that a procedure of this type is extremely burdensome from both a cost and time standpoint.

[0012] In fact, the creation of a prosthesis having this level of customisation requires processing specifically designed around the patient’s bone measurements, thus leading to the generation of a substantially unique piece.

[0013] Thus, there is a strongly felt need in the sector to develop new operating methods, as well as new instruments, capable of providing an approach and solutions that are more generalised and universally applicable without, however, losing the advantages assured by the current level of customisation, thanks to which a satisfactory structural correspondence between the implanted prosthesis and the bone structure it replaces is ensured.

[0014] In this context, the technical task at the basis of the present invention is to propose a method for selecting a femoral prosthesis which overcomes at least some of the aforementioned drawbacks of the prior art.

[0015] In particular, it is an object of the present invention to provide a method capable of reducing the times and costs of selecting and obtaining the prosthesis, while at the same time maintaining an optimal correspondence between the selected prosthesis and bone structure to be repaired.

[0016] The stated technical task and specified objects are substantially achieved by a method comprising the technical features disclosed in one or more of the appended claims.

[0017] According to the present invention, a computer-executable method for selecting a femoral prosthesis is shown.

[0018] The method is carried out by acquiring a 3D model of a patient’s femur at a pre-operative stage. Then a plurality of identification parameters comprising at least one engagement parameter and a bone parameter are measured on the 3D model.

[0019] The engagement parameter is representative of a size and / or shape of a portion of the prosthesis suitable to engage a femoral bone as a function of one or more lines of cutting to be performed thereon.

[0020] The bone parameter is representative of a size and / or shape of a portion of the prosthesis adapted to replicate a respective portion of the femoral bone.

[0021] Then a database comprising prosthetic data identifying a plurality of femoral prostheses according to respective identification parameters is queried.

[0022] The femoral prostheses are subdivided into a plurality of distinct families, wherein each femoral prosthesis has the same engagement parameter as each other femoral prosthesis of the same family and at least one bone parameter different from a corresponding bone parameter of at least one other prosthesis of the same family.

[0023] Finally, a femoral prosthesis having the highest number of matches between the identification parameters thereof and those measured on the 3D image is selected from within the database.

[0024] Advantageously, the method presented here makes it possible to identify the specific femoral prosthesis that is best suited to the patient’s anatomy in a precise, rapid and accurate manner.

[0025] A system and a database are also described and claimed.

[0026] The system comprises a plurality of femoral prostheses identified by respective identification parameters.

[0027] The femoral prostheses are further subdivided into families based on said identification parameters.

[0028] The database stores prosthetic data identifying a plurality of femoral prostheses belonging to the system.

[0029] The dependent claims, which are incorporated herein by reference, correspond to different embodiments of the invention.

[0030] Additional features and advantages of the present invention will emerge more clearly from the approximate and thus non-limiting description of a preferred but not exclusive embodiment of a method for selecting a femoral prosthesis, as illustrated in the appended drawings, in which:

[0031] - figure 1 shows a femoral prosthesis;

[0032] - figures 2A-2B show in detail one component of the prosthesis in figure 1 ;

[0033] The method described herein makes it possible to select, in a particularly efficient and precise manner, a femoral prosthesis 1 to be used during a bone reconstruction operation.

[0034] The method has particular application in the selection of a prosthesis for reconstructing a distal end of a femur.

[0035] The method is executable by a computer, i.e. any electronic device comprising one or more processing units, processors, and electronic components endowed with a capacity to compute and to manipulate inputs required for the correct execution of the method itself, which are presented and described in detail further below in the present description.

[0036] In this context, the claimed method is carried out by acquiring a three- dimensional model of a patient’s femur at a pre-operative stage.

[0037] In other words, one acquires, by means of known methods (for example by means of a tomography technique or by reconstructing a three- dimensional model from two-dimensional X-ray images or else by means of magnetic resonance techniques), information making it possible to generate and acquire a three-dimensional representation of the femur on which the bone repair operation will be performed.

[0038] Once the image has been acquired, one proceeds to measure a plurality of identification parameters in that 3D model.

[0039] The identification parameters are generally parameters which enable specific structural and dimensional characteristics of the femur to be determined and categorised so as later to be able to identify the femoral prosthesis 1 that best reproduces and / or approximates those characteristics.

[0040] In greater detail, the identification parameters comprise at least one engagement parameter and at least one bone parameter.

[0041] In this context, the engagement parameter is a parameter representative of a size and / or shape of a portion of the femoral prosthesis 1 suitable and configured to engage a femoral bone as a function of one or more lines of cutting to be performed on that femoral bone.

[0042] In fact, in a bone reconstruction operation it is necessary to perform cuts on the patient’s femoral bone to enable the placement and coupling of the prosthesis (which in turn replicates the bone structure that was removed following the cuts).

[0043] The bone parameter, on the other hand, is representative of a size and / or shape of a portion of the prosthesis adapted to replicate a respective portion of said femoral bone.

[0044] Therefore, the engagement parameter identifies the structure, shape and size of the cuts and thus of the bone surface against which the prosthesis will be abutted or in any case of elements configured to interact directly with the bone to be repaired, whereas the bone parameter identifies the shape and size of the portion of bone that will be replaced by the prosthesis.

[0045] In greater detail, the present invention has particular application for reconstructing the distal end of the femur through the implementation of a prosthesis of the ball-and-socket type.

[0046] This type of prosthesis envisages replicating the joint mechanics of the knee by means of a main body 2 replacing the structure of the distal end of the femur and which is couplable to the tibia via a medial sphere.

[0047] The medial sphere in turn operatively defines at least in part a ball joint capable of ensuring optimal mobility of the limb at the end of the operation. In general, the engagement parameter comprises at least one of: a length and / or height and / or a maximum width and / or an inclination of one or more surfaces adapted and configured to abut against a respective surface of the distal end (this is specifically understood to mean the surface of the distal end following the completion of the cuts).

[0048] The engagement parameter thus defines in general a structure, geometry, and shape of the inner surfaces of the prosthesis, i.e. the surfaces configured to engage bone surfaces appropriately cut and shaped to receive that prosthesis.

[0049] In other words, in the specific case of prostheses of the ball-and-socket type, the engagement parameter can thus comprise a profile of the internal cut, hence the length, height, width, inclination of the inner surfaces of the prosthesis (i.e. the portion configured to define the seat suitable to accommodate the medial sphere), or parameters defined based on a couplability of the prosthesis with the patient’s femoral bone, such as, for example, the corresponding dimensions of the surfaces or bone structures of the patient that will abut against or in general will have to interact with one or more portions of the prosthesis.

[0050] The bone parameter, on the other hand, comprises at least one of: a radius of a sphere approximating the profile of a portion of the femoral prosthesis 1 replicating a femoral condyle, a maximum width and / or height of a portion of the prosthesis replicating a posterior and / or distal portion of the femoral condyle, a maximum width and / or height and / or an angle of inclination of a main axis of extension of a portion of the prosthesis replicating the intercondylar fossa.

[0051] The bone parameters can also comprise other parameters representative of the structure of the prosthesis, such as, for example, the orientation of the trochlea or the length and width of the anterior shield or the distal width or the height and width of the posterior condyles.

[0052] The bone parameter thus defines in general a structure, geometry, and shape of the outer surfaces of the prosthesis, i.e. the surfaces configured to replicate an outer structure / surface of one or more bone portions.

[0053] Advantageously, the bone parameters can also be defined on the basis of elements and anatomical structures external to the bone itself but nonetheless such as to be in direct contact with the bone.

[0054] In other words, the bone parameters can also be defined on the basis of parameters relating, for example, to connective tissues destined to engage the prosthesis 1 and / or comprise such parameters relating for example to connective tissues.

[0055] Operatively, the method described herein thus envisages making a series of measurements on the 3D image of the femur and identifying thereon the parameters that define the prosthesis best matching the patient’s specific anatomy, mainly considering the structure of the femoral bone and potentially also the structure and the characteristics of the adjacent tissues.

[0056] For example, by measuring the sizes of the cuts to be performed on the femoral bone it is possible to obtain the engagement parameter simply by defining the dimensions of the inner surface of the prosthesis that best match those sizes.

[0057] Similarly, by measuring for example a size of the patient’s condyles and / or acquiring data on the intercondylar fossa, it is possible to determine and define the corresponding bone parameters.

[0058] In more detail, the method is carried out by measuring at least one engagement parameter corresponding to a profile of the cuts to be performed on the femur, i.e. such at least one engagement parameter therefore corresponds to at least one of a length, height, width, inclination of at least one of the inner surfaces of the prosthesis 1 .

[0059] The bone parameters in this specific context comprise: an anteroposterior dimension of the patient’s femur, a length of the posterior condyle, a length of the intercondylar fossa, an orientation of the intercondylar fossa (for example the inclination thereof relative to one or more cutting planes), a sagittal profile of the intercondylar fossa, an axial profile of the intercondylar fossa, an axial or lateral position of the intercondylar fossa, and a dimensional measurement of an anterior shield of the prosthesis.

[0060] Once the identification parameters of interest have been acquired, one proceeds to query a specific database comprising prosthetic data identifying a plurality of femoral prostheses catalogued and categorised according to such identification parameters.

[0061] In particular, the femoral prostheses are stored and subdivided within the database into a plurality of distinct families.

[0062] The families are established in such a way that each femoral prosthesis 1 has the same engagement parameter as each other femoral prosthesis 1 of the same family and at least one bone parameter different from a corresponding bone parameter of at least one other prosthesis of the same family.

[0063] Therefore, each family is defined overall by all the femoral prostheses 1 suitable to be applied to a given cutting profile (and thus interfaceable with a femoral bone on which cuts having specific dimensional characteristics have been made) and contains within it a plurality of femoral prostheses 1 characterised by structures adapted to replicate respective bone structures of different sizes.

[0064] Based on the query just described, the specific femoral prosthesis 1 having the highest number of matches between the identification parameters measured on the 3D femur and the identification parameters of the femoral prosthesis is selected from within the database.

[0065] The expression “highest number of matches” is meant to identify the femoral prosthesis 1 that best approximates the highest possible number of parameters identifying the patient’s femoral bone.

[0066] In particular, the method is carried out by querying a database comprising prosthetic data identifying a plurality of femoral prostheses 1 according to respective identification parameters, wherein the femoral prostheses 1 are subdivided into a plurality of distinct families characterised by different values of at least one of the length, height, width, inclination of the inner surfaces of the prosthesis 1 .

[0067] In other words, different families have different values of at least one of the length, height, width, and inclination of the inner surfaces of the prosthesis, whilst the members of each family have the same engagement parameters, i.e. equal values for at least one of the length, height and width of the inner surfaces of the prosthesis, and different bone parameters.

[0068] For the sake of completeness, it is noted that there are different possible implementational situations in which, for example, a same family has the same value for only one of the length, height, width, inclination of the inner surfaces of the prosthesis, without placing particular constraints on the other parameters, or each family has the same value for two or even three of the parameters specified above, without placing particular constraints on the parameters not selected, or also be characterised by identical values of all four of the parameters specified above.

[0069] Advantageously, it is likewise possible to associate with each identification parameter (engagement or bone) a relative weight representative of a level of relevance thereof and the selection of the femoral prosthesis 1 is made also based on that relative weight.

[0070] Preferably, it is likewise possible to acquire at least one biometric parameter of the patient and the selection of the femoral prosthesis 1 can be made also as a function of that biometric parameter, possibly weighed on the basis of a specific relative weight thereof.

[0071] In particular, the biometric parameter can comprise a morphotype and / or a phenotype of the patient, such as, for example, a classification into varus / valgus or according to specific known classifications, e.g. CPAK.

[0072] Advantageously, it is likewise possible to edit or update the database by storing or modifying prosthetic data.

[0073] This operation may be carried out also on the basis of the outcomes of the femoral prosthesis 1 selection step in order to optimise and improve that process.

[0074] For example, if the selected femoral prosthesis 1 is not sufficiently satisfactory from the standpoint of adaptability to the patient’s anatomy, it will be possible to modify the relative weight of the parameters and / or modify the identification data of the prosthesis and repeat the database query in order to identify a femoral prosthesis 1 better suited to the bone repair operation that is being planned.

[0075] Once the femoral prosthesis 1 has been selected, it is possible, moreover, to query a tracking table in which tracking data of the femoral prostheses 1 are stored, i.e. data identifying the presence and preferably the position of the selected femoral prosthesis 1 within a storage warehouse.

[0076] In other words, the method envisages identifying a specific femoral prosthesis 1 and also identifying the position in which that prosthesis is to be found to enable an easier acquisition and possibly also automate a process of dispatching the prosthesis from the warehouse to the facility in which the bone reconstruction operation will be performed.

[0077] Advantageously, if it is not possible to identify a femoral prosthesis 1 sufficiently conforming and corresponding to the acquired identification parameters (or if the selected femoral prosthesis 1 is not present within the storage warehouse) it is possible to generate an alert signal.

[0078] For example, this signal can be generated when the database does not comprise prosthetic data identifying a femoral prosthesis 1 having at least one identification parameter corresponding to the identification parameters measured on the 3D femur.

[0079] It is worth highlighting that the correspondence is preferably a numerical correspondence and a confidence threshold can be set to determine when there is or is not a correspondence between the values analysed.

[0080] For example, a value can be considered to correspond if it falls within a range of values centred on the reference value and extending from -10% to + 10% of the reference value.

[0081] For example, considering a bone parameter corresponding to the radius of a sphere approximating the profile of a lateral condyle, given a measurement of 20 mm on the 3D image, one may consider all the femoral prostheses having a radius of a sphere approximating the profile of the portion of prosthesis which replicates the lateral condyle in the range of between 18 mm and 22 mm as conforming to that measurement. In this context, it is also possible to define a level of conformity in which prostheses with parameters coming closer to the specific value measured on the 3D image have a higher level of conformity than prostheses which, despite still being within the range indicated, are in any case farther from the reference value.

[0082] In the event of complete equivalence between several prostheses (also after considering the number of parameters found to conform, the relative weight of each parameter and the level of conformity thereof) it is also possible to provide an indication and selection of all the prostheses considered to conform sufficiently to the patient’s anatomy.

[0083] In order to further optimise the selection of the most suitable femoral prosthesis 1 , the present method can also be carried out in such a way as to display the 3D model on a video terminal, superimposing thereon a graphic representation of the selected femoral prosthesis 1 .

[0084] On the video terminal it is thus possible to highlight any identification parameters for which there is not conformity between the 3D model and the graphic representation of the selected femoral prosthesis 1 .

[0085] In this manner it is possible to verify whether the selection of the relative weights of the various identification parameters is satisfactory or whether it is instead necessary to introduce modifications so as to select a different femoral prosthesis 1 that better approximates different structural features of the bone.

[0086] The method may also be carried out to store a result of the femoral prosthesis 1 selection step by populating a database of results.

[0087] In other words, the data of the specific femoral prostheses 1 selected in successive iterations of the method are stored in the database of results.

[0088] It is thus possible to apply a statistical analysis on the database of results by determining a selection incidence curve for the femoral prostheses 1 as a function of the identification parameters thereof.

[0089] Therefore, it is possible to generate a curve which represents the statistical use of the femoral prostheses 1 as a function of their structural and dimensional characteristics.

[0090] This information may be used to optimise the management of the families of femoral prostheses 1 by reducing the number of (or even eliminating) the femoral prostheses 1 that over time are not selected or selected a statistically insignificant number of times and instead increasing the number of femoral prostheses 1 whose use is more frequent.

[0091] In this manner, one optimises the possibility of always having available a given femoral prosthesis 1 that is suited to the patient’s anatomy in the event of a specific request for the performance of an arthroplasty operation.

[0092] It is also possible to use this information for the subsequent design of new prostheses, in order to populate the most widely used families of femoral prostheses 1 with a higher number of different copies and create new femoral prostheses 1 having identification parameters falling among the values of those that are most widely used.

[0093] If, for example, one finds a large use of prostheses belonging to adjacent families, i.e. ones having values of the engagement parameters immediately consecutive to each other, it will be possible to develop a new family having engagement parameters which are intermediate between the ones of the two most widely used families, thus also improving the precision with which the prostheses 1 can be selected.

[0094] Therefore, the method described thus far makes it possible to identify and select the femoral prosthesis 1 that best satisfies the patient’s needs, thanks to an optimised approach whereby the available femoral prostheses are categorised by means of objective criteria that can be rapidly and efficiently selected and if necessary also modified, while providing useful feedback for inventory management and for the design of new femoral prostheses 1 .

[0095] The present application also relates to a knee arthroplasty system comprising a plurality of families of prostheses for reconstructing a femoral bone.

[0096] These prostheses are specifically designed for the reconstruction of a distal end of the femoral bone and, as stated, essentially comprise a main body 2 and a medial sphere.

[0097] The main body, which may be seen in detail in figures 2A-2B, has a front portion 4 and two joint portions 5 that extend away from the front portion 4. The front portion 4 replicates the structure of the intercondylar fossa of the distal end of the femur and defines a portion of the prosthesis 1 identified as the front shield, whereas the joint portions 5 replicate the structure of the medial condyle and lateral condyle of the femur, respectively.

[0098] The arched shape of the front portion 4 and of the joint portions 5 combine to delineate a seat intended to abut at least partially against the femoral bone and inside which the medial sphere is accommodated.

[0099] The seat is defined in particular by a plurality of inner surfaces all delimited by sides that are either perpendicular or parallel to each other and, in particular, all the inner surfaces are shaped so as to be perpendicular, during use, to a sagittal plane of the patient.

[0100] Optionally, all the inner surfaces are delimited by sides that are either perpendicular or parallel to each other (thus perpendicular, during use, to the sagittal plane of the patient), with the exception of the inner surface corresponding to the front portion 4, i.e. the inner surface directly corresponding to the portion of prosthesis 1 that defines the front shield thereof.

[0101] In this context, said surface is inclined relative to the others and, specifically, it is inclined so as to form, during use, an angle ranging between - 5° and + 5° relative to the patient’s sagittal plane.

[0102] The medial sphere in turn is coupled with a tibial prosthesis 6 in order to interconnect the patient’s tibia and femur.

[0103] The use of a structure of the ball-and-socket type with the presence of the medial sphere makes it possible to define, operatively, a joint endowed with a high degree of freedom, such as to optimally replicate a healthy knee joint, resulting in a particularly efficient, robust prosthesis 1 and reducing the times (and thus also the costs) of a subsequent patient movement rehabilitation process.

[0104] Each family of femoral prostheses 1 comprises a respective plurality of femoral prostheses 1 whose structure is defined by at least one engagement parameter and one bone parameter.

[0105] These parameters are the same as listed above and thus the engagement parameter is representative of a size and / or shape of a portion of the prosthesis suitable to engage the femoral bone as a function of one or more lines of cutting to be performed thereon and the bone parameter, by contrast, is representative of a size and / or shape of a portion of the prosthesis adapted to replicate a respective portion of said femoral bone.

[0106] In this context, analogously to what was described above, each femoral prosthesis 1 has the same engagement parameter as each other femoral prosthesis 1 of the same family and at least one bone parameter different from a corresponding bone parameter of at least one other femoral prosthesis 1 of the same family.

[0107] In particular, the femoral prostheses 1 are subdivided into a plurality of distinct families characterised by different values of at least one of the length, height, width, inclination of the inner surfaces of the prosthesis 1 .

[0108] In other words, different families have different values of at least one of the length, height, width, and inclination of the inner surfaces of the prosthesis 1 whereas the members of each family have the same engagement parameters, i.e. equal values of at least one of the length, height and width, and inclination of the inner surfaces of the prosthesis 1 , and different bone parameters.

[0109] In this manner, it is possible to classify the femoral prostheses 1 , making them more easily identifiable and providing a wide array of solutions wherein the best solution is more easily identifiable and made immediately available thanks to the presence of a kit of different femoral prostheses 1 characterised by different shapes and sizes. Advantageously, each prosthesis 1 can be further catalogued, categorised or defined based on a biometric parameter representing an indication of potential patient phenotypes and / or morphotypes.

[0110] In other words, the biometric parameter identifies the respective prosthesis, defining an adaptability thereof to specific known phenotypes and / or morphotypes.

[0111] In particular, within every family of femoral prostheses there thus exist prostheses specifically adapted to best accommodate the needs of the specific patient morphotype / phenotype, such as, for example, a varus or valgus form of the hip-knee-ankle (HKA) angle according to the traditional classification or joint line obliquity (distal, neutral, proximal apex), according to the CPAK classification.

[0112] A customisation of the prosthesis 1 is thus made possible, while at the same time avoiding the need to design and produce individual prostheses 1 for every arthroplasty operation.

[0113] The present invention also relates, moreover, to a database comprising prosthetic data identifying a plurality of femoral prostheses 1 belonging to a system according to what was described in the previous paragraphs and thus subdivided according to respective identification parameters.

[0114] In particular, the femoral prostheses 1 are subdivided into a plurality of distinct families, wherein the femoral prostheses 1 of a same family have the same engagement parameter and at least one different bone parameter.

[0115] Moreover, the database is specifically queryable during the execution of the method described above.

[0116] In particular, the database comprises prosthetic data identifying a plurality of femoral prostheses as a function of respective identification parameters, wherein the femoral prostheses are subdivided into a plurality of distinct families characterised by different values of at least one of the length, height, width of the inner surfaces of the prosthesis.

[0117] In other words, different families have different values for at least one of length, height, and width of the inner surfaces of the prosthesis whereas the members of each family have the same engagement parameters, i.e. equal values for at least one of the length, height and width of the inner surfaces of the prosthesis, and different bone parameters. Preferably, the database also comprises a tracking table of femoral prostheses 1 containing tracking data of a position of the femoral prostheses 1 within a storage warehouse.

[0118] The database can further comprise within it (allocated to a suitable local or distributed storage unit) a database of results adapted to store each femoral prosthesis selected by carrying out the selection method presented herein.

[0119] Advantageously, in all the aspects claimed and described, the present invention achieves the proposed objects, overcoming the aforementioned drawbacks in the prior art, by providing the user with a method for selecting femoral prostheses 1 , a system comprising such femoral prostheses 1 and a database enabling the desired prosthesis 1 to be identified within the system by carrying out the various operations envisaged by the method.

Claims

CLAIMS1. Computer-executable method for selecting a femoral prosthesis (1 ) comprising the steps of:- acquiring a 3D model of a patient's femur at a pre-operative stage;- measuring on said 3D model a plurality of identification parameters comprising at least one engagement parameter representative of a size and / or shape of a portion of the prosthesis (1 ) suitable to engage a femoral bone as a function of one or more lines of cutting to be performed on said femoral bone and selected from: a length, height, width, inclination of at least one inner surface of the prosthesis (1 ) and a plurality of bone parameters representative of a size and / or shape of a portion of the prosthesis (1 ) adapted to replicate a respective portion of said femoral bone and selected from: an anteroposterior dimension of the patient’s femur, a length of the posterior condyle, a length of the intercondylar fossa, an orientation of the intercondylar fossa, a sagittal profile of the intercondylar fossa, an axial profile of the intercondylar fossa, an axial or lateral position of the intercondylar fossa, a dimensional measurement of an anterior shield of the prosthesis;- querying a database comprising prosthetic data identifying a plurality of femoral prostheses (1 ) according to respective identification parameters, said femoral prostheses (1 ) being subdivided into a plurality of distinct families, wherein each femoral prosthesis (1 ) has the same engagement parameter as each other femoral prosthesis (1 ) of the same family and at least one bone parameter different from a corresponding bone parameter of at least one other prosthesis (1 ) of the same family;- selecting from said database a femoral prosthesis (1 ) with the highest number of matches between the identification parameters measured on the 3D femur and the identification parameters of said femoral prosthesis (1 )-2. Method according to claim 1 , wherein said femoral prosthesis (1 )comprises a prosthesis (1 ) of the ball-and-socket type for reconstructing a distal end of said femoral bone, and wherein said engagement parameter comprises at least one of: a maximum height and / or width of one or more surfaces adapted to abut against a respective surface of said distal end; and wherein said bone parameter comprises at least one of: a radius of a sphere approximating the profile of a portion of the femoral prosthesis (1 ) replicating a femoral condyle, a maximum width and / or height of a portion of the prosthesis (1 ) replicating a posterior and / or distal portion of said femoral condyle, a maximum width and / or height and / or an angle of inclination of a main axis of extension of a portion of the prosthesis (1 ) replicating the intercondylar fossa.

3. Method according to claim 1 or 2, comprising a step of acquiring at least one biometric parameter of the patient and said step of selecting a femoral prosthesis (1 ) is also performed according to said at least one biometric parameter.

4. Method according to claim 3, wherein the at least one biometric parameter comprises at least one of: a morphotype and a phenotype of the patient.

5. Method according to any one of the preceding claims, comprising a step of associating with each identification parameter a relative weight representative of a level of relevance of said identification parameter and said step of selecting a femoral prosthesis (1 ) is also performed as a function of said relative weight.

6. Method according to any one of the preceding claims, comprising a step of editing or updating the database by storing or modifying prosthetic data.

7. Method according to any one of the preceding claims, comprising a stepof querying a tracking table containing tracking data of a position of the femoral prostheses (1 ) to verify a presence and preferably a position of the selected prosthesis (1 ) within a storage warehouse.

8. Method according to any one of the preceding claims, comprising a step of generating an alert signal when the database does not include any prosthetic data identifying a femoral prosthesis (1 ) having at least one identification parameter corresponding to the identification parameters measured on the 3D femur.

9. Method according to any one of the preceding claims, comprising the steps of:- displaying the 3D model on a video terminal;- superimposing a graphic representation of the selected femoral prosthesis (1 ) on said 3D model;- highlighting on said video terminal any non-conforming identification parameters between the 3D model and said graphic representation of the selected prosthesis (1 ).

10. Method according to any one of the preceding claims, comprising the steps of:- storing a result of said femoral prosthesis (1) selection step by populating a database of results;- applying a statistical analysis to said database of results by determining a selection incidence curve for said prostheses (1 ) as a function of the respective identification parameters.

11. A knee arthroplasty system comprising a plurality of families of prostheses (1 ) for reconstructing a femoral bone, preferably for reconstructing a distal end of said femoral bone, wherein each family of prostheses (1 ) comprises a respective plurality of femoral prostheses (1 ),and wherein a structure of each femoral prosthesis (1 ) is defined by at least one engagement parameter representative of a size and / or shape of a portion of the prosthesis (1 ) adapted to engage a femoral bone as a function of one or more lines of cutting to be performed on said femoral bone and selected from: a length, height, width, inclination of at least one inner surface of the prosthesis (1 ) and at least one bone parameter representative of a size and / or shape of a portion of the prosthesis (1 ) adapted to replicate a respective portion of said femoral bone and selected from: an anteroposterior dimension of the patient’s femur, a length of the posterior condyle, a length of the intercondylar fossa, an orientation of the intercondylar fossa, a sagittal profile of the intercondylar fossa, an axial profile of the intercondylar fossa, an axial or lateral position of the intercondylar fossa, a dimensional measurement of an anterior shield of the prosthesis; each femoral prosthesis (1 ) having the same engagement parameter as each other femoral prosthesis (1 ) of the same family and at least one bone parameter different from a corresponding bone parameter of at least one other prosthesis (1 ) of the same family.

12. System according to claim 11 , wherein each prosthesis (1 ) comprises a prosthesis (1 ) of the ball-and-socket type for reconstructing a distal end of the femoral bone, and wherein said engagement parameter comprises at least one of: a height and / or a maximum width of one or more surfaces adapted to abut against a respective surface of said distal end; and wherein said bone parameter comprises at least one of: a radius of a sphere approximating the profile of a portion of the femoral prosthesis (1 ) replicating a femoral condyle, a maximum width and / or height of a portion of the prosthesis (1 ) replicating a posterior and / or distal portion of said femoral condyle, a maximum width and / or height and / or an angle of inclination of a main axis of extension of a portion of the prosthesis (1 ) replicating the intercondylar fossa.

13. System according to claim 11 or 12, wherein each prosthesis is also categorised according to a biometric parameter identifying potential patient morphotypes and / or phenotypes.

14. Database comprising prosthetic data identifying a plurality of femoral prostheses (1 ) according to respective identification parameters comprising at least one engagement parameter representative of a size and / or shape of a portion of the prosthesis (1 ) suitable to engage a femoral bone as a function of one or more lines of cutting to be performed on said femoral bone and selected from: a length, height, width, inclination of at least one of the inner surfaces of the prosthesis (1 ) and at least one bone parameter representative of a size and / or shape of a portion of the prosthesis (1 ) adapted to replicate a respective portion of said femoral bone and selected from: a mediolateral dimension of the patient’s femur, an anteroposterior dimension of the patient’s femur, a length of the posterior condyle, a length of the intercondylar fossa, an orientation of the intercondylar fossa, a sagittal profile of the intercondylar fossa, an axial profile of the intercondylar fossa, an axial or lateral position of the intercondylar fossa, a dimensional measurement of an anterior shield of the prosthesis, said femoral prostheses (1 ) being subdivided into a plurality of distinct families, wherein the femoral prostheses (1 ) of the same family have the same engagement parameter and at least one different bone parameter.

15. Database according to claim 14, comprising a tracking table of said femoral prostheses (1 ) containing tracking data of a position of said femoral prostheses (1 ) within a storage warehouse.

16. Database according to claim 14 or 15, comprising a results database adapted to store each femoral prosthesis (1 ) selected by performing said selection method.

17. Database according to any one of claims 14 to 16, wherein said database is queryable during the execution of a method for selecting prostheses (1 ) according to any one of claims 1 to 10 and / or said database is configured to store prosthetic data identifying a plurality of femoral prostheses (1 ) belonging to a system according to claim 11 or 12.

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