Patent Publication Number: US-2020297356-A1

Title: Multifunction Device for Prosthetic Surgery and Corresponding Method of Use

Description:
FIELD OF THE INVENTION 
     The present invention concerns a multifunction device for hip prosthetic surgery interventions. 
     The multifunction device is of the convertible type, in that it can be used as a milling device, for example to make an acetabular seating to install an acetabular cup of a hip, or as a positioning device, for example to position and release the acetabular cup of a hip in the acetabular seating previously made. 
     BACKGROUND OF THE INVENTION 
     The devices that can be used during hip prosthetic surgery interventions are known. 
     In particular, it is known that during the steps of preparing the acetabular seating and implanting the corresponding prosthesis, many and different devices are required, the choice and conformation of which can also depend on the chosen surgical access route such as, for example, the posterolateral route or the anterior route. 
     In normal operating practice milling devices are used, to make coordinated and mating acetabular seatings suitable for the disposition and implant of corresponding acetabular cups, and positioning devices to allow the correct positioning, also angular, of the prostheses as above in the acetabular seatings and for their release into position. 
     The surgeon is therefore, on each occasion, called upon to choose in advance the devices to be used during the surgical operation, based on the chosen access route and, moreover, to use different devices for the above-described operations of milling the acetabular seating, positioning and release of the prosthesis. 
     In particular, known milling devices comprise a handling body provided with a proximal end, to which a drive member of the manual or motorized type is operatively associated, and a distal end, to which is operatively associated a milling tool that can be used for the realization of hemispherical acetabular seatings, or in any case with a spherical cap, suitable to install coordinated acetabular cups of the hip prostheses. 
     The rotational motion supplied by the drive member is transmitted to the milling tool through a transmission unit inside the handling body itself, for example a transmission system with cardan joints. 
     However, both the drive member and also the milling tool have connection portions able to be associated only with the determinate handling body which has attachment portions, mating with the connection portions as above, different from each other. 
     This requires the surgeon to purchase an entire tool kit from a single supplier. 
     Often, however, there is the need to choose a handling body that has a specific conformation, a milling tool or a drive member from different manufacturing companies, for example for practical reasons, but also due to needs related to the characteristics of the patient to be operated on such as the underlying pathology, age, body weight or the suffering of possible allergies to some materials. 
     In this regard, known milling devices are typically made of steel. The latter is an allergic material that, due to wear, rubbing or impacts, can release traces of metals, such as nickel and chromium, which can induce allergic reactions in the patient undergoing surgical treatment. 
     The positioning devices also comprise a handling body which at the proximal end, or in a nearby position, has an ergonomic grip, or handle, to allow the surgeon to correctly position the acetabular cup in the acetabular seating made, and at the distal end has a positioning element to which the acetabular cup as above can be associated, temporarily. 
     The desired angular position of the acetabular cup can be reached by acting on a transmission member that allows the rotation of the positioning element and therefore of the acetabular cup. 
     The transmission member is driven manually and can be provided in correspondence with the proximal end or in another position along the handling body, and is connected to the positioning element by means of a suitable transmission unit. 
     Once correctly positioned, the acetabular cup is released into the acetabular seating by means of a release mechanism, for example a pressure or spring mechanism, activated in correspondence with the transmission member by means of a trigger, or by means of a lever or by mechanical impact. 
     However, in the event the release mechanism is activated by mechanical impact, the stresses produced are discharged on the transmission unit causing its rapid deterioration. 
     The handling body of the positioning devices typically has an asymmetrical curved conformation to allow the surgeon to easily reach the acetabular seating. 
     One disadvantage of this conformation is that the mechanical impact to activate the release mechanism causes a moment of forces which tends to misalign, both axially and also angularly, the positioned acetabular prosthesis. 
     It is also known that the devices described above have to be subjected to washing and sterilization operations after each intervention, and have to therefore be made of a material suitable to withstand the attack of aggressive chemical agents, such as iodine-based disinfectants, and to withstand temperatures in the order of about 130° C. 
     In addition, known devices are complicated and consist of numerous components, which are difficult to disassemble, for sterilization, and to assemble, in order to be available during the surgical operation. 
     It is not unusual, in fact, that an incorrect assembly of the devices as above can cause malfunctions during the surgical operation. 
     There is therefore the need to perfect a device for prosthetic surgery that can overcome at least one of the disadvantages of the state of the art. 
     In particular, one purpose of the present invention is to provide a multifunction device for prosthetic surgery which can selectively be a milling device or a positioning device. 
     Another purpose of the present invention is to provide a multifunction device for prosthetic surgery with which it is possible to operatively associate any drive member, any milling tool, and any positioning element whatsoever with respect to both the proximal and also the distal end. 
     Another purpose of the present invention is to provide a multifunction device for prosthetic surgery provided with a release mechanism of the acetabular cup the activation of which does not cause a deterioration of the transmission unit. 
     Another purpose of the present invention is to provide a multifunction device for prosthetic surgery made of hypoallergenic and biocompatible material. 
     Another purpose of the present invention is to provide a multifunction device for prosthetic surgery made up of a limited number of components. 
     Another purpose of the present invention is to provide a multifunction device for prosthetic surgery which is easy to disassemble and assemble. 
     The Applicant has studied, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages. 
     SUMMARY OF THE INVENTION 
     The present invention is set forth and characterized in the independent claims. The dependent claims describe other characteristics of the present invention or variants to the main inventive idea. 
     In accordance with the above purposes, a multifunction device for prosthetic surgery able to be converted from a milling configuration, to be used as a milling device for hip prosthetic surgery, to a positioning configuration, to be used as a positioning device to position an acetabular cup of a hip prosthesis comprises: 
     a single tubular oblong handling body  12 , which develops along an operating axis, provided with a distal end and a proximal end opposite each other, inside the handling body there is a unit to transmit the rotary motion from the distal end to the proximal end, the transmission unit ending in respective attachment portions, respectively distal and proximal, which are interchangeable with each other; 
     one or more acetabular milling cutters able to be releasably connected to one of the attachment portions in the milling configuration as above; 
     a positioning element able to be releasably fastened on one side directly to one of the attachment portions and on the other side to an acetabular cup of a hip prosthesis, in the positioning configuration as above; 
     a transmission element able to be releasably fastened to one of the attachment portions opposite the attachment portion to which the acetabular milling cutter or the positioning element is fastened, the transmission element being configured so that, in the milling configuration or respectively in the positioning configuration as above, it can be used to transmit, by means of the transmission unit, a rotation from one of the attachment portions to the other of the attachment portions, respectively associated with a specific acetabular milling cutter or with an acetabular cup associated with the positioning element, or again the transmission element, in the positioning configuration as above, is able to be struck by a striker member in order to transmit an impact force, through the handling body and the positioning element, to forcefully position the acetabular cup associated with the positioning element. 
     In accordance with some embodiments, there is provided a method to use the multifunction device for prosthetic surgery in a milling configuration, to be used as a milling device for hip prosthetic surgery, and in a positioning configuration, to be used as a positioning device to position an acetabular cup of a hip prosthesis. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other aspects, characteristics and advantages of the present invention will become apparent from the following description of some embodiments, given as a non-restrictive example with reference to the attached drawings wherein: 
         FIG. 1  is a lateral view of a handling body of a multifunction device for multifunction prosthetic surgery in accordance with some embodiments; 
         FIG. 2  is an exploded view of  FIG. 1 ; 
         FIG. 3  is an exploded lateral view of  FIG. 1 ; 
         FIG. 4  is a perspective view of a component of  FIG. 2 ; 
         FIG. 5  is a section along a vertical plane of  FIG. 4 ; 
         FIG. 6  is a perspective view of the multifunction device for prosthetic surgery, in accordance with the embodiment of  FIG. 1 , when it is used as a milling device; 
         FIG. 7  is an exploded view of  FIG. 6 ; 
         FIG. 8  is a section view of two components of  FIG. 7 ; 
         FIG. 9  is a section view of two components of  FIG. 7 ; 
         FIG. 10  is a perspective view of the multifunction device for prosthetic surgery, in accordance with the present invention, when it is used as a positioning device; 
         FIG. 11  is an exploded view of  FIG. 10 ; 
         FIG. 12  is a perspective view of a detail of  FIG. 11 ; 
         FIG. 13  is a section view of two components of  FIG. 11 ; 
         FIG. 14  is a section view of three components of  FIG. 11 ; 
         FIG. 15  is a lateral view of a handling body of a multifunction device for multifunction prosthetic surgery according to another embodiment; 
         FIG. 16  is an exploded view of  FIG. 15 ; 
         FIG. 17  is an exploded lateral view of  FIG. 15 ; 
         FIG. 18  is a perspective view of a component of  FIG. 16 ; 
         FIG. 19  is a lateral view of  FIG. 18 ; 
         FIG. 20  is a section along a vertical plane of  FIG. 18 ; 
         FIG. 21  is a perspective view of the multifunction device for prosthetic surgery, in accordance with the embodiment of  FIG. 15 , when it is used as a milling device; 
         FIG. 22  is an exploded view of  FIG. 21 ; 
         FIG. 23  is a section view of two components of  FIG. 21 ; 
         FIG. 24  is a section view of two components of  FIG. 21 ; 
         FIG. 25  is a perspective view of the multifunction device for prosthetic surgery, in accordance with the embodiment of  FIG. 15 , when it is used as a positioning device; 
         FIG. 26  is an exploded view of  FIG. 25 ; 
         FIG. 27  is a perspective view of a detail of  FIG. 11 ; 
         FIG. 28  is a view of an enlarged detail of  FIG. 25 ; 
         FIG. 29  is a section view of three components of  FIG. 28 ; 
         FIG. 30  is a view of an enlarged detail of  FIG. 25 ; 
         FIG. 31  is a section view of three components of  FIG. 30 . 
     
    
    
     To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings. It is understood that elements and characteristics of one embodiment can conveniently be incorporated into other embodiments without further clarifications. 
     DETAILED DESCRIPTION OF SOME EMBODIMENTS 
     We will now refer in detail to the various embodiments of the invention, of which one or more examples are shown in the attached drawings. Each example is supplied by way of illustration of the invention and shall not be understood as a limitation thereof. For example, the characteristics shown or described insomuch as they are part of one embodiment can be adopted on, or in association with, other embodiments to produce another embodiment. It is understood that the present invention shall include all such modifications and variants. 
     Embodiments described using the attached drawings concern a multifunction device for prosthetic surgery indicated as a whole with reference number  10   a  and  10   b  in the attached drawings, according to the condition in which it is converted and used. 
     The multifunction device is able to be converted to be used, in accordance with a milling configuration, as a milling device  10   a  for hip prosthetic surgery, in particular to make an acetabular seating, and, in accordance with a positioning configuration, as a positioning device  10   b  for positioning an acetabular cup  11  of a hip prosthesis in the acetabular seating as above. 
     The multifunction device comprises a single tubular oblong handling body  12  which develops along an operating axis A. 
     The single handling body  12  is provided with a distal end  13  and with a proximal end  14  opposite each other. 
     Inside the handling body  12  there is a transmission unit  27  of the rotary motion from the distal end  13  to the proximal end  14 , the transmission unit  27  ending in respective attachment portions  15 ,  16  which are interchangeable with each other. 
     Hereafter, for ease of explanation, reference may also be made to a distal attachment portion  15  and a proximal attachment portion  16 , meaning, however, that they can be used indifferently for the functions that will be described in the following document, since they are interchangeable. 
     The multifunction device, also, comprises one or more acetabular milling cutters  17  able to be releasably connected to one of the attachment portions  15 ,  16  in the milling configuration as above. 
     Furthermore, the multifunction device comprises a positioning element  20  able to be releasably fastened on one side directly to one of the attachment portions  15 ,  16  and on the other side to an acetabular cup  11  of a hip prosthesis, in said positioning configuration. 
     Furthermore, the multifunction device comprises a transmission element  21  able to be releasably fastened to one of the attachment portions  16 ,  15  opposite the attachment portion  15 ,  16  to which the acetabular milling cutter  17  or the positioning element  20  is fastened, the transmission element  21  being configured so that, in the milling configuration as above or respectively in the positioning configuration as above, it can be used to transmit, by means of the transmission unit  27 , a rotation from one of the attachment portions  16 ,  15  to the other of the attachment portions  15 ,  16 , respectively associated with the specific acetabular milling cutter  17  or with the acetabular cup  11  associated with the positioning element  20 . 
     Or, again, the positioning element  20 , in the positioning configuration, is able to be struck by a striker member to transmit an impact force, through the handling body  12  and the positioning element  20 , to forcefully position the acetabular cup  11  associated with the positioning element  20 . 
     In accordance with some embodiments, the handling body  12  has an elongated conformation in the direction of the operating axis A as above passing through the attachment portions  15 ,  16  and comprises a first shell  22  and a mating second shell  23  able to be stably coupled to each other in a releasable manner in order to house, inside, the transmission unit  27  as above. 
     The transmission unit  27  allows the transmission of the rotary motion, generated by the drive member, from the proximal portion  16  to the distal portion  15  or vice versa. 
     Advantageously the first shell  22  and the second shell  23  are identical and specular and are coupled to each other by means of tightening ring nuts  24  present on both the distal end  13  and also the proximal end  14 , coaxially with the respective attachment portions  15 ,  16 . 
     The configuration described, allows to simplify the assembly and disassembly of the handling body  12 , both for the surgical operation and also to sterilize all its components. 
     The handling body  12  has at least one inclined segment to aid the surgeon in moving and positioning the multifunction device toward the patient&#39;s acetabulum during the surgical operation. 
     Advantageously, the handling body  12  has two specular inclined segments  12   a,    12   c,  in correspondence with the distal attachment portion  15  and the proximal attachment portion  16  angled with respect to said operating axis A, and a linear segment  12   b,  comprised between the inclined segments  12   a,    12   c,  parallel to the operating axis A. 
     Advantageously, the inclined segments  12   a,    12   c  are angled with respect to the operating axis A by the same angle a comprised between about 15° and about 35°. 
     The handling body  12  has a conformation symmetrical with respect to a central axis S orthogonal to the operating axis A and passing through the center of the handling body  12 . 
     The handling body  12  has a conformation symmetrical with respect to a coupling plane passing through the operating axis A and with respect to which the first shell  22  and the second shell  23  are coupled. 
     This conformation of the handling body  12  is important both when the multifunction device is used as a milling device  10   a  to make an acetabular seating, and also when the device is used as a positioning device  10   b  to position and release the acetabular cup  11 . 
     Furthermore, the symmetrical conformation of the handling body  12  allows it to be used indiscriminately in one direction or another of the operating axis A as above. 
     The transmission unit  27  comprises rotation shafts  28   a,    28   b,    28   c,  respectively corresponding to the segments  12   a,    12   b,    12   c,  and connected by cardan joints  29  which allow the transmission of the rotary motion with respect to the incident directions of the segments  12   a,    12   b,    12   c.    
     In this specific case, the rotation shafts  28   a,    28   c  are the two outermost ones and are respectively connected on one side to the rotation shaft  28   b  and on the other, always by means of a cardan joint  29 , to a connection interface  30  configured to be associated respectively with the proximal attachment portion  16  and with the distal attachment portion  15 . 
     The transmission unit  27  is operatively inserted inside the handling body  12 , between the first shell  22  and the second shell  23 . 
     For this purpose, the first shell  22  and the second shell  23  comprise a plurality of support cavities  25  and passage cavities  26  suitable to contain, once coupled, the transmission unit  27 . 
     In particular, the transmission unit  27  comprises bearings  31  which, during use, are positioned resting in the support cavities  25  and allow the rotation of the shafts  28   a,    28   b,    28   c  without any friction against the internal walls of the first shell  22  and the second shell  23 . 
     Especially when the multifunction device is used as a milling device  10   a,  the bearings  31 , as well as preventing friction of the rotation shafts  28   a,    28   b,    28   c,  are configured to absorb the vibrations that are generated due to the inertia of the rotating members allowing a greater control of the milling device  10   a  by the surgeon. 
     According to some embodiments, the attachment portions  15 ,  16  are, in particular, the same and interchangeable each comprising a base  32 , a coupling head  35  and a plate  34  located intermediate. 
     The base  32  is provided with a connection compartment  33  with a shape mating with that of the connection interface  30  for the operative connection to the transmission unit  27 . 
     In accordance with some embodiments, shown in  FIGS. 1-14 , both the base  32  and also the connection interface  30  are provided, on a lateral surface, respectively with connection holes  36   a,    36   b  which during use are aligned in order to house an interference element which allows to make respectively the distal attachment portion  15  and the proximal attachment portion  16  integral at least temporarily with the transmission unit  27 . 
     In accordance with possible solutions, the interference element can be chosen in a group comprising a pin, a screw, a rivet or other similar or comparable elements. 
     In accordance with some embodiments, shown in  FIGS. 15-31  the base  32  is provided, on a lateral surface, with connection holes  36   a  ( FIGS. 18-19 ) which during use are aligned and house a respective interference element  55  ( FIG. 17 ) which is associated with the connection interface  30  in order to allow to make at least temporarily respectively the attachment portions  15 ,  16  integral with the transmission unit  27 . 
     The plate  34  and the coupling head  35  are configured to cooperate with one of the acetabular milling cutters  17  as above, with the positioning element  20 , with a connection adapter possibly fastened to a respective acetabular milling cutter  17 , with another connection adapter  19  fastened to a motorized drive member, or directly to the transmission element  21 . 
     For this purpose, the plate  34  is provided with a support surface  34   a  which, during use, is coordinated with and facing, on each occasion, striker surfaces  37 ,  39 ,  40  respectively of the acetabular milling cutter  17 , of the connection adapters  19  and of the transmission element  21 . In particular, the support surface  34   a  and the striker surfaces  37 ,  39 ,  40  can be coupled with more or less wide play,  FIGS. 1-14 , or they can be located in contact,  FIGS. 15-31 . 
     The coupling head  35  develops from the plate  34  in the direction of the operating axis A, on the opposite side to that of the base  32 . 
     To promote the engagement of the coupling head  35  with the acetabular milling cutter  17 , with the positioning element  20 , with one of the connection adapters possibly fastened to a respective acetabular milling cutter  17 , with one of the other connection adapters  19  fastened to the motorized drive member, or directly with the transmission element  21 , the coupling head  35  can have a prismatic shape. 
     Especially in the case where the multifunction device is used as a milling device  10 a, the prismatic shape of the coupling head  35  allows to improve the transmission of the rotary motion both on the drive member side, and also on the acetabular milling cutter  17  side. 
     In particular, the coupling head  35  can have a polygonal-shaped section, in particular, but not limited to, quadrangular ( FIGS. 1-14 ), or hexagonal ( FIGS. 15-31 ), to allow a selectively releasable connection with the acetabular milling cutter  17 , with the positioning element  20 , with one of the connection adapters possibly fastened to a respective acetabular milling cutter  17 , with one of the other connection adapters  19  fastened to the motorized drive member, or directly with the transmission element  21 . 
     The hexagonal shape of the coupling head  35  allows, once the coupling with the acetabular milling cutter  17  has been made, to distribute the connection force in a more homogeneous manner between the coupling head  35  and an attachment part  45  of the acetabular milling cutter  17  as above. With the same transmitted force, the hexagonal shape, also, allows to reduce the sizes of the aperture  46  of the acetabular milling cutter  17  that houses the coupling head  35  as above. 
     In accordance with some embodiments, the coupling head  35  has clamping means  56  configured for a stable connection with the acetabular milling cutter  17 , with the positioning element  20 , with one of the connection adapters possibly fastened to a respective acetabular milling cutter  17 , with one of the other connection adapters  19  fastened to the motorized drive member, or directly with the transmission element  21 . 
     In accordance with some embodiments, shown in  FIGS. 1-14 , the clamping means  56  comprise at least one presser device  42  (see for example  FIGS. 4-5, 8-9, 13-14 ) configured to generate an interference with the translation in the direction of the operating axis A in order to ensure the clamping of the acetabular milling cutter  17 , of the positioning element  20 , of the connection adapters  19 , or of the transmission element  21 . In this case, the coupling head  35  has internally a housing compartment  41 , open toward the outside, to house the presser device  42  as above. For this purpose, at least one portion of the presser device  42  has to exit the profile of the coupling head  35  in a direction orthogonal to the operating axis A. 
     The housing compartment  41  is advantageously through so that possible organic residues, or possible condensation can easily be discharged during/after the washing and sterilization process. 
     In accordance with possible solutions, the presser device  42  can be chosen in a group comprising a spring presser, a ball presser, a spring and ball presser. 
     In the embodiment described here, the presser device  42  is of the spring and ball type and comprises an interference element  42   a  and an elastic element  42   b  that generates an elastic thrust on the interference element  42   a  in a direction orthogonal to the operating axis A. 
     In accordance with some embodiments, shown in  FIGS. 15-31 , the clamping means  56  comprise at least one magnetic element  57  (see for example  FIGS. 18, 20, 23-24, 29, 31 ), for example a permanent magnet, such as an annular element, or ring, of magnetic material. The at least one magnetic element  57  is advantageously configured to selectively go on each occasion in abutment with striker surfaces  37 ,  39 ,  40  respectively of the acetabular milling cutter  17 , of the connection adapters  19  and of the transmission element  21 . 
     The magnetic element  57  can be inserted in a specific seating made in the plate  34  and can define part of the support surface  34   a.    
     Some embodiments, shown in  FIGS. 6-9  and  FIGS. 21-24 , concern a milling device  10   a  which comprises the handling body  12 , one or more acetabular milling cutters  17 , and possibly one or more connection adapters able to be fastened on one side directly to the distal attachment portion  15  and on the other side to a respective one of said acetabular milling cutters  17 . 
     In accordance with possible solutions, the acetabular milling cutter  17  can comprise a support part  43  that has a substantially hemispherical shape internally hollow and configured to support a plurality of cutting edges  44  distributed on it, in a desired manner. 
     The acetabular milling cutter  17  can, also, comprise an attachment part  45  stably fixed to the base of the support part  43  and provided with the contact surface  37  and an aperture  46  configured to cooperate respectively with the plate  34  and with the coupling head  35  of the distal attachment portion  15  or of the proximal attachment portion  16 . 
     Advantageously, the shape of the aperture  46  is mating with the shape of the coupling head  35  so that no connection adapters are needed between them. 
     In accordance with the embodiment, shown in  FIG. 8  and in  FIG. 23 , the acetabular milling cutter  17  is configured to couple directly with the distal attachment portion  15  or with the proximal attachment portion  16  with respect to the operating axis A. 
     In accordance with the embodiment, shown in  FIGS. 6-9 , the coupling head  35  once inserted into the aperture  46  in the direction of the operating axis A, will have penetrated therein by a height such that the presser device  42  is above the aperture  46  and below the support part  43  so as to axially clamp by interference the distal attachment portion  15  or the proximal attachment portion  16  with the acetabular milling cutter  17 . At the same time the surface  37  of the attachment wall  45  can be resting on the support surface  34   a  of the plate  34  in order to increase the overall coupling surface and, therefore, improve the stability of the connection. 
     In accordance with the embodiment, shown in  FIGS. 21-24 , the coupling head  35  once inserted into the aperture  46  in the direction of the operating axis A, will have penetrated therein by height such that the support surface  34   a  part of which has the magnetic element  57  goes into contact with the surface  37  of the attachment wall  45  suitably made of a metal material that has magnetic properties which allow an attraction suitable to make a stable connection. 
     The milling device  10   a,  also, comprises one or more further connection adapters  19  able to be fastened as a replacement of the transmission element  21 , in the milling configuration, on one side directly to a respective attachment portion  16 ,  15  and on the other side to a motorized drive member. 
     In accordance with the embodiment of  FIG. 7  and  FIGS. 21-22  three connection adapters  19  are shown each of which is configured to operatively connect a different motorized drive member, not shown, which will have a mating coupling compartment, with one of said distal attachment portions  15  or proximal attachment portion  16 . 
     Each connection adapter  19  comprises a universal attachment part  47 , able to be fastened to the proximal attachment portion  16  or to the distal attachment portion  15 , and a specialized attachment part  48 , able to be fastened to the specific motorized drive member. 
     The universal attachment part  47  is provided with a connection cavity  49  that has a shape mating with that of the coupling head  35 . 
     In accordance with the embodiment, shown in  FIG. 9 , the universal attachment part  47  has at least one interference channel  50  passing from the connection cavity  49  toward the outside and suitable to at least partly house the presser device  42 . 
     The coupling head  35  is inserted in the connection cavity  49  so that the presser device  42  is partly inserted in the interference channel  50  as above. 
     Advantageously, the universal attachment part  47  is provided with one or more interference channels  50  orthogonal to the operating axis A and angled with respect to each other so that the coupling head  35  is positioned so that the presser device  42  is aligned with any one of the angled directions of the interference channels  50 . 
     Advantageously, the interference channels  50  are through toward the outside so that possible organic residues, or possible condensation can easily be discharged during/after the washing and sterilization process. 
     In accordance with the embodiment, shown in  FIG. 24 , the connection between the coupling head  35  and the connection adapter  19  occurs between the support surface  34   a  part of which has the magnetic element  57  and the striker surface  39 . Also in this case, the particular hexagonal shape of the coupling head  35  allows a more effective transmission of the torque. 
     In some cases, it is necessary to drive the milling device  10   a  by means of the transmission element  21 . The transmission element  21  is configured to be connected directly to the distal attachment portion  15  or to the proximal attachment portion  16  and is typically driven by the surgeon in the final step of the process of making the acetabular seating. 
     Embodiments in which the multifunction device is converted into positioning device  10   b  are described using the  FIGS. 10-14  and the  FIGS. 25-31  and comprise the handling body  12  as above, the positioning element  20  able to be fastened on one side directly to the distal attachment portion  15  and on the other side to an acetabular cup  11  of a hip prosthesis. 
     The positioning element  20  comprises a connection body  51  provided with a connection seating  53  for housing the distal attachment portion  15  or the proximal attachment portion  16 , and a holding element  52  for the connection to the acetabular cup  11 . 
     The connection body  51  advantageously has a flared shape in the direction of the holding element  52  so as not to interfere at other points with the acetabular cup  11 . 
     In accordance with the embodiment, shown in  FIGS. 25-31 , the positioning element  20  and the transmission element  21  are provided with respective releasable clamping devices  58 ,  59  which allow respectively to make the positioning element  20  integral with the handling body  12  and to clamp the rotation of the transmission element  21  which determines the motion of the transmission unit  27 . 
     In this way, once the correct position of the acetabular cup  11  with respect to suitable surgical references has been determined, this position remains unchanged even in case of accidental movements of the surgeon during the operating technique, or during the strikes inflicted by the striker member to transmit the impact force. 
     The releasable clamping devices  58 ,  59  each comprise a respective tightening lever  60 ,  61  which allows to selectively make integral respectively the positioning element  20  and the transmission element  21  with the handling body  12 . 
     The tightening lever  60  of the releasable clamping device  58  of the positioning element  20  has an open position, suitable to allow the engagement of the positioning element  20  on an attachment portion  15 ,  16  and its correct angular position with respect to the operating axis A, and a closing position, suitable to make the positioning element  20  integral with the handling body  12 . 
     The closing position is necessary to guarantee that, during the impact action of the striker member on the transmission element  21  for the fixing in position of the acetabular cup  11  in the acetabular seating, made previously or already present, the strike inflicted transmits the force required for the fixing as above. In fact, otherwise, the strike inflicted by the striker member could be ineffective and transmit the impact force onto the surgeon&#39;s arm. 
     The correct angular position with respect to the operating axis A is the one that guarantees the minimum bulk of the tightening lever  60  during the surgical technique and can be defined by aligning suitable references on the handling body  12  and on the positioning element  20 . 
     In addition, in operating techniques of revision of prosthetic implants of the hip, the opening position allows a rotation of the acetabular cup  11 , previously fixed to the positioning element  20 , to allow a correct alignment thereof for the insertion of fixing screws. 
     The tightening lever  61  of the releasable clamping device  59  of the transmission element  21  has an open position, suitable to allow the engagement of the transmission element  21  on an attachment portion  15 ,  16  and its rotation with respect to the operating axis A in order to activate the transmission unit  27  and transmit the rotary motion from the distal end  13  to the proximal end  14 , and a closing position, suitable to clamp the transmission element  21  to the handling body  12  preventing the activation of the transmission unit  27 . 
     The tightening levers  60 ,  61  are configured to at least partly wind the handling body  12  in correspondence with the distal end  13  and the proximal end  14  or vice versa. In particular, the tightening action of the tightening levers  60 ,  61  as above acts on the respective portion of the handling body  12  close to the ring nuts  24  on the opposite side with respect to the attachment portions  15 ,  16 . 
     In accordance with the embodiment, shown in  FIGS. 10-14 , the holding element  52  is fixed. 
     In accordance with the embodiment, shown in  FIGS. 25-31 , the holding element  52  is mobile in rotation, about the operating axis A, in a housing cavity  62  of the positioning element  20 . 
     The housing cavity  62  is open on one side toward the connection seating  53 , so as to allow the holding element  52  to connect with the attachment portion  15 ,  16  or with the attachment portion  16 ,  15 , and on the opposite side toward the outside so as to allow the connection of the holding element  52  with the acetabular cup  11 . 
     The holding element  52  has a threaded tip for the anchoring to the acetabular cup  11 . 
     In particular, when the tightening lever  60  of the releasable clamping device  58  of the positioning element  20  is in the closing position and the tightening lever  61  of the releasable clamping device  59  of the transmission element  21  is in the open position, it is possible, by rotating the latter, to firmly screw the acetabular cup  11  to the positioning element  20 . 
     Furthermore, the screwing action allows to compact the holding element  52  and the acetabular cup  11  toward the attachment portion  15 ,  16  creating a very stable tightening. In accordance with the embodiment, shown in  FIGS. 25-31 , the transmission element  21  has the shape of a handle intended for the grip to rotate and position the acetabular cup  11  as described above and intended to be struck by a striker member to fix the acetabular cup  11  in its seating. 
     In particular,  FIG. 28-29 , the transmission element  21  comprises a coupling end  63  provided with the releasable clamping device  59  and an opposite abutment end  64  suitable to be struck by a striker member, for example by a surgical hammer. 
     The coupling end  63  is, also, provided with a coupling seating to receive one of the attachment portions  15 ,  16 . 
     The acetabular cup  11  has a substantially hemispherical hollow shape and is provided, on its top, with a holding hole  54  in which the holding element  52  of the positioning element  20  is temporarily inserted, by interference ( FIG. 10-14 ) or by screwing ( FIGS. 25-31 ). 
     In accordance with one aspect of the present invention, the transmission element  21  and the positioning element  20  are resting only on the corresponding ring nuts  24  of the handling body  12 , in the direction of the operating axis A, so that the strike of the striker member on the transmission element  21  is transmitted through the handling body  12  onto the positioning element  20  without affecting the transmission unit  27 . 
     In this way, once the strike is generated on the transmission element  21 , the acetabular cup  11  disengages from the holding element  52  of the positioning element  20  and remains in position in the acetabular seating made with the milling device  10   a  waiting to be permanently fixed therein by means of for example, screws or surgical cement. 
     In the event the acetabular cup  11  is of the helicoidal type, the positioning device  10   b  is, also, suitable to screw it into the acetabular seating made with the milling device  10   a.    
     In accordance with one aspect of the present invention, at least the handling body  12  and the acetabular milling cutter  17  are made of biocompatible and hypoallergenic metal material. 
     In preferred embodiments, at least the handling body  12  and the acetabular milling cutter  17  are made of titanium which ensures high biocompatibility with the human body preventing problems of postoperative rejection; it is in fact biocompatible and hypoallergenic. 
     Advantageously, the connection adapters, the additional connection adapters  19 , the transmission element  21 , and the positioning element  20  can also be made of biocompatible and hypoallergenic metal material such as, for example, titanium. 
     In other embodiments, at least the handling body  12  and the acetabular milling cutter  17  are made of steel. 
     Embodiments of the present invention concern a method to use the multifunction device for prosthetic surgery described above. 
     The method to use the multifunction device provides the conversion from a milling configuration, to be used as a milling device  10   a  for prosthetic hip surgery, to a positioning configuration, to be used as a positioning device  10   b  to position an acetabular cup  11  of a hip prosthesis; the method as above comprises:
         making available a single tubular oblong handling body  12  which develops along the operating axis A, provided with the distal end  13  and the proximal end  14  opposite each other, inside the handling body  12  there is the transmission unit  27  of the rotary motion from the distal end  13  to the proximal end  14 , the transmission unit  27  ending in the respective attachment portions  15 ,  16 , respectively distal and proximal, which are interchangeable with each other;   when the device is converted into the milling configuration as above, releasably connecting the specific acetabular milling cutter  17  to one of the attachment portions  15 ,  16  in the milling configuration as above;   when the device is converted into the positioning configuration as above, releasably fastening the positioning element  20  on one side directly to one of the attachment portions  15 ,  16  and on the other side to the acetabular cup  11  of a hip prosthesis;   when the device is converted into the positioning configuration as above, releasably fastening the transmission element  21  to one of the attachment portions  16 ,  15  opposite the attachment portion  15 ,  16  to which the acetabular milling cutter  17  or the positioning element  20  is fastened, the transmission element  21 , in the milling configuration as above or respectively in the positioning configuration as above, transmitting, by means of the transmission unit  27 , a rotation from one of the attachment portions  16 ,  15  to the other one of the attachment portions  15 ,  16 , respectively associated with the specific acetabular milling cutter  17  or with the acetabular cup  11  associated with the positioning element  20 , or again the positioning element  20 , in the positioning configuration as above, is struck by a striker member to transmit an impact force, through the handling body  12  and the positioning element  20 , to forcefully position the acetabular cup  11  associated with the positioning element  20 .       

     It is clear that modifications and/or additions of parts and/or steps may be made to the multifunction device for prosthetic surgery and to the corresponding method of use as described heretofore, without departing from the field of the present invention as defined by the claims. 
     It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art shall certainly be able to achieve many other equivalent forms of multifunction device for prosthetic surgery and corresponding method of use, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby. 
     In the following claims, the references in brackets have the sole purpose to facilitate reading and they must not be considered as restrictive factors with regard to the field of protection claimed in the specific claims.