U.S. patent application number 14/777717 was filed with the patent office on 2016-09-29 for set of instruments for the implantation of an acetabular prosthesis.
The applicant listed for this patent is MEDACTA INTERNATIONAL SA. Invention is credited to Massimiliano BERNARDONI, Matteo PONZONI, Alberto SICCARDI, Francesco SICCARDI.
Application Number | 20160278939 14/777717 |
Document ID | / |
Family ID | 48366375 |
Filed Date | 2016-09-29 |
United States Patent
Application |
20160278939 |
Kind Code |
A1 |
SICCARDI; Alberto ; et
al. |
September 29, 2016 |
SET OF INSTRUMENTS FOR THE IMPLANTATION OF AN ACETABULAR
PROSTHESIS
Abstract
A set of instruments for the implantation of an acetabular
prosthesis (100), comprises at least one tool (1; 2) designed to
operate in the acetabular cavity (101) of a patient and at least
one emitter (3) jointly associable with said tool and designed to
emit a control signal (31) to be aligned with a reference signal
(30) which identifies a correct orientation of said tool (1; 2)
relative to the acetabular cavity (101).
Inventors: |
SICCARDI; Alberto; (Sonvico,
CH) ; SICCARDI; Francesco; (Vico Morcote, CH)
; BERNARDONI; Massimiliano; (Figino, CH) ;
PONZONI; Matteo; (Montano Lucino, IT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MEDACTA INTERNATIONAL SA |
Castel San Pietro |
|
CH |
|
|
Family ID: |
48366375 |
Appl. No.: |
14/777717 |
Filed: |
March 13, 2014 |
PCT Filed: |
March 13, 2014 |
PCT NO: |
PCT/IB2014/059715 |
371 Date: |
September 16, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 2017/00725
20130101; A61B 17/16 20130101; A61B 17/92 20130101; A61F 2002/3097
20130101; A61B 17/1746 20130101; A61B 17/1666 20130101; A61F 2/34
20130101; A61F 2/4609 20130101; A61B 2017/568 20130101; A61F
2002/4687 20130101; A61F 2/4657 20130101 |
International
Class: |
A61F 2/46 20060101
A61F002/46; A61B 17/17 20060101 A61B017/17; A61B 17/16 20060101
A61B017/16; A61F 2/34 20060101 A61F002/34; A61B 17/92 20060101
A61B017/92 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 18, 2013 |
IT |
MI2013A000405 |
Claims
1. A set of instruments for the implantation of an acetabular
prosthesis comprising: at least one tool designed to operate in the
acetabular cavity of a patient; and at least one emitter jointly
associable with said at least one tool and designed to emit a
control signal to be aligned with a reference signal which
identifies a correct orientation of said at least one tool relative
to the acetabular cavity.
2. The set of instruments according to claim 1, further comprising
an acetabular reference guide which is fixable to a bone site of
the patient separate from the acetabular cavity and with which a
second emitter designed to emit said reference signal can be
jointly associated.
3. The set of instruments according to claim 2, further comprising
an acetabular calibration guide transitorily associable with the
acetabular cavity of the patient according to a desired
orientation, said acetabular calibration guide being jointly
associable with an emitter designed to emit a calibration signal
which identifies the orientation thereof, said reference signal
being able to be calibrated relative to said calibration
signal.
4. The set of instruments according to claim 3, wherein said
acetabular calibration guide comprises a positioning base that
precisely mates with the acetabular cavity of the patient.
5. The set of instruments according to claim 4, wherein said
positioning base has a supporting foot intended to abut against an
internal surface of said acetabular cavity, and a plurality of
positioning arms intended to engage with different points on the
periphery of said acetabular cavity.
6. The set of instruments according to claim 5, wherein said
positioning arms comprise a central positioning arm intended to be
inserted in the acetabular fossa.
7. The set of instruments according to claim 5, wherein said
positioning arms comprise a lower positioning arm intended to abut
against the lower acetabular lip and an upper positioning arm
intended to abut against the upper acetabular lip of said
acetabular cavity.
8. The set of instruments according to claim 3, wherein the same
emitter can be associated alternatively with the different tools
and with the acetabular calibration guide.
9. The set of instruments according to claim 8, wherein said
emitter is mounted on a connector configured to be snap fitted to
adaptors associated with the different tools as well as to an
adaptor associated with the acetabular calibration guide.
10. The set of instruments according to claim 9, wherein said
second emitter is mounted on a connector configured to be snap
fitted to an adaptor associated with the acetabular reference
guide, said emitter and said second emitter with respective
connectors being interchangeable with each other.
11. The set of instruments according to claim 2, wherein said
emitters are optical collimators configured to emit optical
signals, two of which can be adjusted with each other overlapping
the track of said optical signals projected on a surface plate.
12. The set of instruments according to claim 1, wherein one of
said tools comprises an acetabular reamer.
13. The set of instruments according to claim 1, wherein one of
said tools comprises an impactor.
14. The set of instruments according to claim 1, wherein said
emitter is associated, by a pivotable joint, to a connector
configured to be fitted to specific adaptors integral with other
components of the set of instruments.
15. The set of instruments according to claim 14, wherein said
connector comprises a locking screw designed to selectively block
the rotation of the pivotable joint.
Description
TECHNICAL FIELD
[0001] The present invention relates, in its most general aspect,
to a set of instruments for the implantation of an acetabular
prosthesis.
[0002] The invention has useful application in the field of
orthopaedic surgery, with particular reference to interventions
involving a reconstruction of the acetabulum, as in the case, for
example, of total arthroprosthesis or hip resurfacing
arthroplasty.
[0003] The use of endoprostheses to eliminate pain and restore the
function of the hip joint, especially in patients suffering from
osteoarthritis, is a technique that was developed starting from the
second half of the last century and is by now well established in
the medical art.
[0004] In most cases, where both the acetabular cavity and the
femoral head of the patient are compromised by the pathology, a
total arthroprosthesis of the hip, also called THR--acronym for
total hip replacement--is performed. This operating technique
entails the implantation of an acetabular prosthesis in the
patient's pelvis on the one hand and, on the other hand, the
resection of the femoral head and replacement thereof with a
prosthetic stem endowed with an articulating ball that fits into
the aforesaid prosthesis.
[0005] Despite having led to some excellent clinical results in
terms of functional recovery of the joint, arthroprosthesis of the
hip has some major drawbacks. In particular, it has been observed,
due to the reduced diameter of the prosthetic ball, there are
frequent episodes of displacement of the artificial joint; not
rarely, for the same reason, an arthroprosthesis performed without
the necessary precision and expertise may lead to a disparity in
the length of the lower limbs. Finally, arthroprosthesis of the hip
does not enable the patient to engage in sports or other stressful
activities, making this an unsuitable solution especially for
younger patients.
[0006] In order to remedy the drawbacks observed in the art, an
alternative to the traditional arthroprosthesis of the hip has been
developed in recent times, namely, hip resurfacing.
[0007] This approach involves capping the articular surface of the
pelvis and femoral head with metal cups of modest thickness,
thereby preserving both the head and neck of the patient's femur.
This operation makes it possible to maintain a joint diameter that
is close to the physiological one, thus reducing the risk of
displacements and modifications in the length of the limb.
Furthermore, the wear on the components is more limited, with a
consequent lengthening in the average lifespan of the
prosthesis.
[0008] Both operating approaches summarily described here have in
common the need to prepare the surface of the acetabulum and
implant therein an acetabular prosthesis.
[0009] Preparation entails first of all a step of cleaning the
bone, removing in particular the soft tissues and cartilage which
preclude correct visualization of the bony landmarks (e.g. the
acetabular fossa) present on the periphery of the acetabulum.
So-called acetabular reaming is then performed, using a special
tool inserted in the cavity. Acetabular reaming serves to smooth
the internal surface of the cavity in order to prepare it to
receive the acetabular prosthesis.
[0010] Another tool, called an impactor, is used to position and
fix the acetabular prosthesis.
[0011] This tool has a stem, to the end of which the replacement
cotyle is fixed; it enables the prosthetic device both to be
inserted in the bone cavity and mechanically locked in place before
the stem is withdrawn.
[0012] The above-mentioned operations of preparing, positioning and
fixing the acetabular prosthesis within the corresponding pelvic
cavity are extremely critical and delicate steps in an arthroplasty
procedure. The orientation of the acetabular prosthesis, which is
defined by these operations, in fact largely determines the
implant's success in the long term. A correct positioning will
result in an optimal distribution of loads and an ideal stability
of the prosthesis; an incorrect positioning, on the contrary, may
result in a rapid deterioration of the implant or in biological
complications of another kind.
[0013] It should be observed, moreover, that the aforesaid
procedures are complicated by the difficult access to the bone
site, and by the limited visibility of the latter. In particular,
while in the hip arthroprosthesis operations the removal of the
femoral neck serves in some way to make the route toward the
acetabulum more pervious, in hip resurfacing arthroplasty the
surgeon does not enjoy this relative advantage.
[0014] It may further be observed that the use of specific guides
realized with rapid prototyping systems, currently applied in other
orthopaedic surgical procedures, cannot be easily transferred to
operations on the acetabulum.
[0015] In fact, a vast, easily exposable bone area ensuring a
stable positioning on the physical guide is lacking around the
acetabular cavity.
[0016] International patent WO 2011/117644 proposes a set of
instruments that the surgeon can use to perform operations on the
acetabulum, comprising: [0017] locating means, temporarily located
in the acetabulum; [0018] guide means, set in a pre-established
position in relation to the locating means and serving as a guide,
when in that position, for the instruments used to prepare of the
acetabular surface (acetabular reamer) and position and fix the
prosthesis (impactor); [0019] as well as support means for
maintaining the guide means in that position when the locating
means have been removed.
[0020] The aforesaid set of instruments, though satisfactory in
certain respects, is clearly very complex in its use. The aforesaid
guide means also have a considerable bulk, which may hamper the
surgeon during his/her operation.
[0021] The technical problem at the basis of the present invention
is thus to devise set of instruments that enables a correct
positioning of the tools for preparing the acetabular cavity and
positioning an acetabular prosthesis, and which is more compact and
simpler to use than prior art devices.
[0022] The aforesaid technical problem is solved by a set of
instruments for the implantation of an acetabular prosthesis,
comprising:
[0023] at least one tool designed to operate in the acetabular
cavity of a patient;
[0024] at least one emitter, jointly associable with said tool and
designed to emit a control signal to be aligned with a reference
signal that identifies a correct orientation of said tool relative
to the acetabular cavity.
[0025] In a preferred embodiment, the emitter consists of an
optical collimator, for example a laser projector, configured to
emit an optical control signal, for example a laser beam. The
optical control signal can be aligned with a reference optical
signal, consisting, for example, of a second laser beam, so as to
collimate the spots of the two signals projected onto a target
surface.
[0026] It should be noted, moreover, that the possibility of using
other prior art technologies for generating and aligning control
and reference signals is not ruled out. For example, such signals
could be represented by ultrasound waves that are aligned by
equalizing the reflection times relative to a target surface.
[0027] As may be easily understood by a person skilled in the art,
the alignment of the optical collimator with a reference optical
signal provides a simple guide system for the surgical tools used
to implant the acetabular prosthesis, thus defining an advantageous
alternative to the physical guide structures known in the art. By
aligning the light beam of the collimator with the reference
signal, the surgeon can in fact control the degree of rotational
freedom of a tool whose operating head is inserted into the
acetabular cavity.
[0028] It should be noted that the same inventive idea is
applicable, mutatis mutandis, to any other technologies for
generating and aligning the signals that might be used.
[0029] Moreover, it should be noted that the inventive idea can
similarly be applied to the various tools subsequently used to
prepare the acetabular cavity and in the subsequent steps of
inserting and fixing the acetabular prosthesis. Such tools may
include, for example, an acetabular reamer and/or an impactor for
the acetabular prosthesis to be implanted.
[0030] It may be noted that the reference signal can be obtained
and maintained with different methods.
[0031] If an optical collimator is used to generate an optical
control signal, the corresponding reference optical signal can be
processed, for example, by means of software using images of the
bone site of the patient and projected onto a target surface.
[0032] Preferably, however, the reference signal is obtained with a
second emitter, which is jointly associated with a bone structure
of the patient that is not involved in the operation of the
surgical tools to be oriented.
[0033] The set of instruments thus comprises an acetabular
reference guide fixable to a bone site of the patient which is
separate from the acetabular cavity and with which a second emitter
designed to emit said reference signal can be jointly associated.
Preferably, the bone site is chosen on the same hip bone that has
the acetabular cavity.
[0034] In the preferred case of an optical collimator used to
generate the (optical) control signal, an optical collimator (for
example, a laser projector) is used in the same way to generate the
reference signal.
[0035] The above-mentioned solution has the advantage of providing
a reference relative to the patient's hip bone, so that any
movements of the bone do not prejudice the correct calibration of
the reference provided.
[0036] The set of instruments according to the present invention
can advantageously comprise an acetabular calibration guide that
can be transitorily associated with the patient's acetabular cavity
according to a desired orientation, said acetabular calibration
guide being jointly associable with an emitter designed to emit a
calibration signal which identifies the orientation of the
acetabular guide itself, said reference signal being able to be
aligned with said calibration signal.
[0037] Once again, in the preferred case of an optical collimator
used to generate the (optical) control and reference signals, an
optical collimator (for example a laser projector) is used in the
same way to generate the calibration signal.
[0038] The acetabular calibration guide can be represented, in
particular, by a physical structure, preferably rod-shaped, which
is temporarily inserted into the acetabular cavity. Once the
desired orientation for the rod-shaped structure has been reached,
the signal emitted by the emitter associated with it enables the
reference signal provided by the second emitter to be calibrated.
Therefore, once the acetabular calibration guide has been removed,
the remaining reference guide, jointly implanted in a portion of
bone at a distance from the acetabulum, enables the orientation
previously assumed by the rod-shaped structure to be exactly
replicated.
[0039] The acetabular calibration guide can comprise, in
particular, a positioning base that precisely mates with the
patient's acetabular cavity.
[0040] This positioning base can be realized, for example, on the
basis of tomographic images of the bone site acquired prior to
surgery.
[0041] The acetabular base enables a specific planned orientation
to be immediately replicated, possibly with the aid of software for
the three-dimensional graphics, in the preoperative phase.
[0042] The positioning base can have, in particular, a supporting
foot intended to abut against the internal surface of said
acetabular cavity, and a plurality of positioning arms intended to
engage with different points on the periphery of said acetabular
cavity.
[0043] A central positioning arm can, for example, be intended to
be inserted in the acetabular fossa, a lower positioning arm to
abut against the lower acetabular lip and an upper positioning arm
to abut against the upper acetabular lip of said acetabular
cavity.
[0044] It should be noted that the same emitter, consisting in
particular of an optical collimator in a preferred embodiment of
the present invention, can be alternatively associated with
different tools (acetabular reamer, impactor) and with the
acetabular calibration guide. The second emitter, associated with
the acetabular reference guide, can also be of a type that is
identical to the first and interchangeable with it.
[0045] The emitter is preferably mounted on a connector, configured
to be snap-fitted to adaptors integral with the various tools as
well as on an adaptor integral with the acetabular calibration
guide. The same emitter can thus be used in the subsequent steps of
calibrating, reaming and implanting the acetabular prosthesis,
while a setting of the emitter relative to the connector is
maintained unchanged.
[0046] The same connector can also be snap fitted to an adaptor
integral with the acetabular reference guide; in this case, as
previously suggested, the two emitters with the respective
connectors are interchangeable with each other.
[0047] The emitters can thus be associated with connectors
configured to be fitted to specific adaptors integral with the
various components of the set of instruments. In particular, the
emitter is preferably associated with the connector by means of a
pivotable joint in order to facilitate calibration of the reference
signal.
[0048] The emitter can further comprise a locking screw serving to
selectively block the rotation of the pivotable joint once the
desired calibration has been reached.
[0049] Additional features and advantages of the present invention
will be apparent from the following description of an example of a
preferred embodiment given by way of non-limiting example with
reference to the appended drawings.
[0050] FIG. 1 represents a perspective view of a first tool and a
connector associated therewith, belonging to the set of instruments
according to the present invention, the first tool being engaged on
a bone site of the patient according to one use configuration;
[0051] FIG. 2 represents a perspective view of a detail of the
first tool in FIG. 1, without the associated connector;
[0052] FIG. 3 represents a perspective view of the first tool in
FIG. 1, with an optical collimator associated with the
connector;
[0053] FIG. 4 represents a perspective view of an adaptor belonging
to the first tool in FIG. 1;
[0054] FIG. 5 represents a perspective view of a second tool and an
optical collimator associated with it by means of a connector, both
belonging to the set of instruments according to the present
invention, the second tool being engaged on a bone site of the
patient according to one use configuration;
[0055] FIG. 6 represents a perspective view of the second tool in
FIG. 5, without the associated connector;
[0056] FIG. 7 represents a perspective view of an adaptor belonging
to the second tool in FIG. 5;
[0057] FIG. 8 represents a perspective view of an acetabular
calibration guide, belonging to the set of instruments according to
the present invention, engaged on a bone site of the patient
according to one use configuration;
[0058] FIG. 9 represents a perspective view of a positioning base,
belonging to the acetabular calibration guide in FIG. 8, engaged on
a bone site of the patient according to one use configuration;
[0059] FIG. 10 represents a perspective view of the positioning
base in FIG. 9, dissociated from the bone site of the patient;
[0060] FIG. 11 represents a perspective view, from a different
angle, of the positioning base in FIG. 10;
[0061] FIG. 12 represents a perspective view of a stem belonging to
the acetabular calibration guide in FIG. 8;
[0062] FIG. 13 represents a perspective view of a detail of the
acetabular calibration guide in FIG. 8, associated by means of a
connector to an optical collimator;
[0063] FIG. 14 represents a perspective view of a connector and of
a detail of an acetabular reference guide belonging to the set of
instruments according to the present invention;
[0064] FIG. 15 represents a perspective view of a femoral guide
belonging to the set of instruments according to the present
invention;
[0065] FIG. 16 represents a first step of a surgical method
implemented using the set of instruments according to the present
invention;
[0066] FIG. 17 represents a second step of a surgical method
implemented by means of the set of instruments according to the
present invention;
[0067] FIG. 18 represents a third step of a surgical method
implemented by means of the set of instruments according to the
present invention.
[0068] The set of instruments according to the present invention
comprises the following components, broadly described below: an
acetabular reamer 1, individually represented in the appended FIGS.
1-3; an impactor 2, individually represented in the appended FIGS.
5-6; and an acetabular calibration guide 5, individually
represented in the appended FIGS. 8-13.
[0069] The set of instruments further comprises an acetabular
reference guide 4, which may be seen in the overall FIGS. 16-18;
and at least two emitters, represented in particular by optical
collimators 3, identical to each other and associable with
connectors 6. The set of instruments can comprise, finally, a
femoral guide 7, individually represented in the appended FIG.
15.
[0070] The components listed above, with the exception of the
femoral guide 7, are used in sequence, according to the procedures
described below, in order to implant an acetabular prosthesis 100,
which is known in itself, inside the acetabular cavity 101 of the
hip bone 102 of a patient. The femoral guide 7 is used, on the
other hand, to perform the resections and drilling operations
necessary to implant a prosthestic femoral component cooperating
with the acetabular prosthesis 100.
[0071] In the preferred embodiment represented here, the acetabular
reamer 1 comprises a stem 11 having a split form, provided on one
end with a head 12 for mounting a reamer, and at the opposite end
with a lateral Chana type handle 13.
[0072] At the point of attachment of the lateral handle 13, an
adaptor 10 is fitted over the stem, the adaptor being configured to
receive one of the connectors 6 of the optical collimators 3.
[0073] The adaptor 10, individually shown in FIG. 4, comprises a
collar-type coupling composed of two semi-cylindrical portions 14a;
14b hinged together. The two semi-cylindrical portions 14a; 14b are
configured to encircle a rectilinear portion of the stem 11 of the
acetabular reamer, abutting beneath a shoulder 17. The closure of
the collar-type coupling is assured by a fastening screw 15, which
passes through lateral flanges 16 of the two semi-cylindrical
portions 14a; 14b.
[0074] Integral with the attachment collar, there is a wedge-like
portion 18 of the adaptor 10, which bears a female coupling 19
intended to enable the snap fitting of a corresponding male
coupling 62 of the connector 6.
[0075] In the preferred embodiment represented here, the impactor 2
comprises a stem 21 having a split form and provided on one end
with a head 22 suitable for carrying an acetabular prosthesis 100,
and on the opposite end with a longitudinal handle 23.
[0076] The stem 21 has an oblique distal portion which follows the
longitudinal handle 23, then a longitudinal portion parallel to the
handle 23, and, finally, a proximal oblique portion which ends with
the head 22, aligned with the handle 23.
[0077] In correspondence of the oblique distal portion 23, an
adaptor 20 is fitted over the stem 21, the adaptor being configured
to receive one of the connectors 6 of the optical collimators
3.
[0078] The adaptor 20, individually shown in FIG. 7, comprises a
forked connector composed of two elastic walls 24a; 24b connected
to a same main body 28. The two elastic walls 24a; 24b are
configured to grasp the distal oblique portion 23 of the impactor
2, abutting below a shoulder 27. The closure of the forked
connector is assured by a connecting screw 25, which passes through
two end flanges 26 formed on the two elastic walls 24a; 24b.
[0079] Opposite the elastic walls 24a; 24b, the main body 28 has a
female coupling 29 intended to enable the snap fitting of a
corresponding male coupling 62 of the connector 6.
[0080] The acetabular reference guide 4 takes the form of a
supporting frame implantable on the hip bone 102 and intended to
support one of the optical collimators 3. It comprises, in
particular, a rectilinear stem 41, which is directly implantable on
the patient's bone and has an adaptor 40 on one end, configured to
receive one of the connectors 6 of the optical collimators 3.
[0081] The adaptor 40, represented in FIG. 14 together with the
connector 6, comprises in particular a female coupling 49 intended
to enable the snap fitting of a corresponding male coupling 62 of
the connector 6. The adaptor 40 also has a release button 48, which
enables the release of the male coupling 62.
[0082] The acetabular calibration guide 5 consists of a supporting
frame transitorily associable with the acetabular cavity 101 of the
patient according to a desired orientation and intended to support
one of the optical collimators 3.
[0083] The acetabular calibration guide 5 comprises, in particular,
an elbow-shaped stem 56, a positioning base 51 mounted on the
proximal end of said stem 56 and an adaptor 50, which is configured
to receive one of the connectors 6 of the optical collimators 3 and
mounted on the distal end of said stem 56.
[0084] The positioning base 51 is configured to mate precisely with
the acetabular cavity 101 of the patient; in order to achieve this
purpose, it is preferably designed on the basis of tomographic
images acquired prior to surgery.
[0085] The positioning base 51 has a supporting foot 52 intended to
abut against the internal surface of the acetabular cavity 101.
[0086] In a distal position relative to said supporting foot 52, at
the edge of the acetabular cavity 101, three positioning arms
branch off: an upper positioning arm 53 intended to abut against
the upper acetabular lip, a central positioning arm 54 intended to
be inserted into the acetabular fossa 104 and a lower positioning
arm 55 intended to abut against the lower acetabular lip.
[0087] The upper 53 and lower 55 positioning arms are coplanar and
at an angle relative to each other that can range from 50 to 200
degrees; the central positioning arm 54, which lies in a plane that
is slightly proximal relative to that of the other two arms 53; 55,
is in an intermediate angular position between them.
[0088] It should be noted, moreover, that whereas the upper 53 and
lower 55 positioning arms have a free T-shaped end, the central arm
54 does not have an enlarged end. The planar extension of the
T-shaped ends follows the profile of the acetabular lips; it may be
observed that the end of the lower arm 55 has a greater extension
than the corresponding end of the upper arm 53.
[0089] Above the positioning base 51 there is provided a through
hole 57, which passes through the supporting foot 52 to permit the
insertion of a pin for temporary fixation to the patient's
bone.
[0090] Above the positioning base 51 there is also provided an
insertion socket 58 oriented at 45.degree. relative to the
extension of the supporting foot 52; the proximal end of the
elbow-shaped stem 56, shown in detail in FIG. 12, is intended to be
snap fitted into the insertion socket 58.
[0091] It should be noted that the curvature of the elbow-shaped
stem 56 is such that the proximal portion of the stem is
substantially aligned with the supporting foot 52.
[0092] The adaptor 50, mounted on the distal end of the
elbow-shaped stem 56, comprises in particular a female coupling 59
intended to enable the snap fitting of a corresponding male
coupling 62 of the connector 6.
[0093] The connector 6, which may be seen in detail in FIG. 14, has
a male coupling 62 that can be snap fitted into any female coupling
19; 29; 49; 59 present on the adaptors 10; 20; 40; 50 described
previously. It should be noted that the male coupling 62 and the
female couplings 19; 29; 49; 59 have an eccentric structure so as
to preclude the relative rotation of the components associated by
means of a snap fit.
[0094] It may be noted that the configuration of the instruments
and of the couplings is such that the female couplings 19; 29; 59
respectively associated with the acetabular reamer 1, the impactor
2 and the acetabular calibration guide 5 have an identical position
and orientation, in the operative configuration, relative to the
acetabular cavity 101.
[0095] The connector 6 comprises a main body 63, which has the male
coupling 62 at one of its ends and a pivotable joint 61 at the
opposite end.
[0096] The pivotable joint 61 consist in particular of a ball
pivotably housed in a U-shaped seat of the main body 63. The
pivotable ball can be associated, by means of a screw integral with
a tightening knob 30, with the optical collimator 3, represented in
this case by a laser projector with an elongated shape.
[0097] Thanks to the pivotable joint 61, it is thus possible to
modify the orientation of the laser projector relative to the main
body 63 of the connector 6 which supports it.
[0098] A locking screw 60 which passes through the main body 63 of
the connector 6 enables the aforesaid pivotable joint 61 to be
locked in the desired position, so as to fix the position of the
laser projector relative to the main body 63.
[0099] The femoral guide 7, which can be part of the set of
instruments according to the present invention, comprises holes 71a
for connecting with a manual support pin and 71b for the insertion
of a temporary fixing pin. The surface 72a represents the cutting
surface on which the surgeon can rest the instrument for resecting
the femoral bone 103. Present on said surface 72a there is a block
72b for limiting the extent of the cut in order to preserve the
greater trochanter.
[0100] We shall now go on to describe, with specific reference to
the appended FIGS. 16-18, a surgical method for the implantation of
an acetabular prosthesis according to the present invention.
[0101] In a first step of said method, following the traditional
operations of incision and preliminary cleaning of the bone site,
one proceeds to position the acetabular calibration guide 5.
[0102] As previously discussed, the acetabular calibration guide
can be associated with the acetabular cavity 101 of the patient in
a precise position so as to define a desired orientation for the
tools which will be subsequently used on the same bone site.
[0103] In this step, the optical collimator 3 must be fixed to the
acetabular calibration guide 5 by means of the connector 6. The
optical collimator 3 projects an optical calibration signal 32,
which serves to define a punctiform spot on a screen or another
target surface 33.
[0104] It may be noted in FIG. 16 that the target screen 33 can
consist of a concentric target for evaluating the accuracy of
alignment of two optical signals.
[0105] Again in this step, one proceeds to implant the previously
defined acetabular reference guide 4 on a portion of the patient's
hip bone 102 at a distance from the acetabular cavity 101. A
respective optical collimator 3 must be associated with this guide,
too. The collimator 3 projects a reference optical signal 30, which
serves to define a punctiform spot on the aforesaid target screen
33.
[0106] The method then envisages a step of calibrating the
reference optical signal 31. To calibrate this signal, the
punctiform spot defined on the target screen is collimated with the
one defined by the optical calibration signal 32 previously
defined, as shown in FIG. 16. The calibration can be performed by
acting upon the pivotable joint 61 of the connector 6 associated
with the acetabular reference guide 4.
[0107] Only after the reference optical signal 30 has been
calibrated, the acetabular calibration guide 5 is extracted so as
to disengage the acetabular cavity 101.
[0108] Subsequently, the acetabular cavity 101 is reamed by means
of the acetabular reamer 1, with which the optical collimator 3
previously fitted to the acetabular calibration guide 5 is
associated. The optical signal projected by the optical collimator
3 now takes on a function of controlling the orientation of the
tool, which is the reason why it will hereinafter be identified as
an optical control signal 30.
[0109] In this step, the surgeon can use the reference optical
signal 31 to orient the tool 1 in the desired direction, that is to
say, in the direction initially assumed by the acetabular
calibration guide 5. To achieve this, as illustrated in FIG. 17, it
is sufficient to collimate the spot of the optical control signal
30 with that of the reference optical signal 31.
[0110] In fact, the morphological identicalness between the
acetabular calibration guide 5 and acetabular reamer 1 ensures
that, in the event of alignment, the optical control signal 30 will
strike in the same point as the optical calibration signal 32,
previously collimated with the reference optical signal 31.
[0111] In a subsequent step of applying the acetabular prosthesis
100, use is made of the previously described impactor 2, which is
fitted with the optical collimator 3 previously used in combination
with the acetabular calibration guide 5 and the acetabular reamer
1.
[0112] In this case as well, as shown in FIG. 18, the surgeon has
the possibility of easily aligning the tool 2 with the chosen
spatial reference by collimating the punctiform spot generated by
the optical control signal 30 with the spot due to the optical
calibration signal 31.
[0113] It is wholly evident that the main advantage of the set of
instruments according to the present invention lies in its singular
structural simplicity.
[0114] The advantage of minimal invasiveness in the surgical area
is likewise important.
[0115] A further advantage lies in the fact that the surgeon is
allowed ample freedom of action during the operations of preparing
the acetabular surface. In fact, the surgeon can freely perform the
preliminary roughing operations according to his/her personal skill
and according to his/her perception of the circumstances, and then
be guided by the laser beam emitted by the tool only on the
occasion of the final finishing operations, aimed at achieving,
with precision, the final shape in the exact position desired.
[0116] Obviously, in order to satisfy specific contingent
requirements, the person skilled in the art may introduce numerous
modifications and variants to the above-described set of
instruments, all remaining within the scope of protection of the
invention as defined in the following claims.
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