Quick attachment clamp for external fixation systems

Abstract

Clamp (1) for an external fixator, preferably of the quick attachment type, comprising: a plurality of attachments (2; 3) for blocking bars and/or bone screws; a connector (5), provided with an at least partially threaded stem (50), which passes through and connects in series said plurality of attachments (2; 3); at least one first attachment (2) comprising two arms (20; 21), connected by a C-shaped flexible bridge (22); said stem (50) passing through said first attachment (2) in an intermediate position between said flexible bridge (22) and the opposite free ends of said arms (20; 21); wherein, at the free ends, said arms (20; 21) define a screw housing seat (23) for a bone screw, said screw housing seat being selectively configurable, varying the deformation of the flexible bridge (22), to clamp bone screws having different diameter.

Claims

1. Clamp for an external fixator, comprising: a plurality of attachments for locking bars and/or bone screws; a connector provided with an at least partially threaded stem, which passes through and connects in series said plurality of attachments; at least one first attachment of said plurality of attachments comprising two arms, connected by a C-shaped flexible bridge; said stem passing through said first attachment in an intermediate position between said flexible bridge and the opposite free ends of said arms wherein, at the free ends, said arms define a screw housing seat for a bone screw; wherein said screw housing seat is selectively configurable, varying the deformation of the flexible bridge, to clamp bone screws having different diameter; wherein said screw housing seat allows at least the clamping of bone screws with diameters of 4 mm, 5 mm and 6 mm; wherein said first attachment also provides for a bar housing seat for a bar of the external fixator; wherein said bar housing seat is defined by an inner profile, substantially shaped as an arc of a circle, of the flexible bridge of the first attachment, said arc of a circle subtending an angle greater than 180°; and wherein at least one of said arms of the first attachment has an enlarged hole substantially wider with respect to the stem that passes through it, so that it does not interfere with said stem as the deformation of the flexible bridge varies, at least in the range which corresponds to the desired variability for the diameter of the bone screws that can be clamped within said housing seat.

2. Clamp according to claim 1, wherein said screw housing seat is defined by specular V-shaped profiles, which are facing and opposite one another, of respective jaws integral with the free ends of the arms of the first attachment.

3. Clamp according to claim 1, wherein said connector provides, at an end of the stem, for a coupling profile for a tightening tool and a tightening knob, with a diameter substantially greater with respect to said coupling profile, for the manual tightening of the connector.

4. Clamp according to claim 3, wherein said tightening knob has means to facilitate the manual gripping thereof, such as knurling or surface coating.

5. Clamp according to claim 1, further comprising a second attachment provided with a bar housing seat or a third attachment provided with one or more screw housing seats.

6. Clamp according to claim 1, wherein the arm of the first attachment that has the enlarged hole is an inner arm with respect to the overall structure of the clamp, namely it is the arm juxtaposed to a second attachment.

7. Clamp according to claim 6, wherein an external arm of said first attachment has a passage hole for said stem; said connector comprises a head integral with the stem and joined thereto with a concave surface; said external arm provides, at an outlet of said passage hole, for a convex seat adapted to contactingly match said concave surface even when the external arm is bent with respect to a condition of perpendicularity to the stem.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 shows a perspective view of a first attachment making part of the clamp for an orthopedic fixator according to the present invention;

(2) FIG. 2 shows a perspective view, according to a different angulation, of the attachment of FIG. 1;

(3) FIG. 3 shows a lateral view, sectioned along a median plane, of the attachment of FIG. 1;

(4) FIG. 4 shows a perspective view of the attachment of FIG. 1 sectioned along a median plane;

(5) FIG. 5 shows a perspective view of a second attachment making part of the clamp for an orthopedic fixator according to the present invention;

(6) FIG. 6 shows a perspective view, according to a different angulation, of the attachment of FIG. 5;

(7) FIG. 7 shows a perspective view of the attachment of FIG. 5 sectioned along a median plane;

(8) FIG. 8 shows a top view of the attachment of FIG. 5;

(9) FIG. 9 shows a lateral view of the attachment of FIG. 5;

(10) FIG. 10 shows a lateral view, sectioned along a median plane, of the attachment of FIG. 5;

(11) FIG. 11 shows a front view of a third attachment of the clamp for an orthopedic fixator according to the present invention;

(12) FIG. 12 shows a lateral view of the third attachment of FIG. 11;

(13) FIG. 13 shows a perspective view of a connector making part of the clamp for an orthopedic fixator according to the present invention;

(14) FIG. 14 shows a perspective view, sectioned along a median plane, of the connector of FIG. 13;

(15) FIG. 15 shows a lateral view, sectioned along a median plane, of the connector of FIG. 13;

(16) FIG. 16 shows a perspective view of an alternative connector for an orthopedic fixator of the type according to the present invention;

(17) FIG. 17 shows a perspective view, according to a different angulation, of the connector of FIG. 16;

(18) FIG. 18 shows a perspective view, according to another different angulation, of the connector of FIG. 16;

(19) FIG. 19 shows a perspective view of a spacer making part of the clamp for an orthopedic fixator according to the present invention;

(20) FIG. 20 shows a perspective view, according to a different angulation, of the spacer of FIG. 19;

(21) FIG. 21 shows a perspective view, sectioned along a median plane, of the spacer of FIG. 19;

(22) FIG. 22 shows a perspective view of a clamp for an external fixator according to the present invention;

(23) FIG. 23 shows a perspective view of the clamp of FIG. 22 according to a different angulation;

(24) FIG. 24 shows a view of detached parts of the clamp of FIG. 22;

(25) FIG. 25 shows a front view of the clamp of FIG. 22 applied to a bar of an external fixator;

(26) FIG. 26 shows a perspective view of the clamp of FIG. 22 applied to two bars of an external fixator matched orthogonally one to another;

(27) FIG. 27 shows a view of detached parts of the configuration of FIG. 26;

(28) FIG. 28 shows a perspective view of the clamp of FIG. 22 applied to a bar of an external fixator matched orthogonally to a bone screw;

(29) FIG. 29 shows a perspective view of a first variant of clamp for an external fixator that can be realized by assembling components of the clamp according to the present invention;

(30) FIG. 30 shows a perspective view, sectioned according to a median plane, of the clamp of FIG. 29;

(31) FIG. 31 shows a view of detached parts of the clamp of FIG. 29;

(32) FIG. 32 shows an external fixator, comprising two clamps of the type in FIG. 29, matched to bone sites corresponding to a patient's wrist articulation;

(33) FIG. 33 shows a second variant of clamp for an external fixator that can be realized by assembling components of the clamp according to the present invention.

MODES FOR CARRYING OUT THE INVENTION

(34) The preferred embodiment described below provides for a system comprising a plurality of components, compoundable for realizing different variants of clamp, identified in the annexed figures with references 1, 1′ and 1″.

(35) Such clamp 1; 1′; 1″, as specified in the previous discussion on the background art, has been projected to function as connecting element of an external orthopedic fixator 100, in particular of a quick fixator of the type illustrated in FIG. 32. The clamp 1; 1′; 1″ is adapted to realize in a quick and efficient manner a temporary rigid connection between the two connecting bars 101 or between a bar 101 and a bone screw 102, of a diameter of 4 mm, 5 mm or 6 mm.

(36) The first variant of clamp 1, illustrated in FIGS. 22-28, comprises a first attachment 2 and a second attachment 3, conveniently held together by a connector 5; the realization also provides for two spacers 6 placed respectively between the jaws of the first attachment 2 and of the second attachment 3. The spacers, in addition to performing a centering function, in the case of the second attachment 3 have also the role of effectively spacing in such a way as to limit the bend of the attachment, preventing all break risks.

(37) The connector 5, individually shown in FIGS. 13-15, comprises a stem 50 provided with a threaded end 55. The opposite end of the stem 50 provides for an enlarged collar 57 for reinforcement and centering, followed by a head 51 joined to the collar 57 by means of a concave surface 52, of substantially spherical shape.

(38) The collar 57 has a diameter that allows to reduce the plays between stem 50 and passage holes of the attachments, favoring the joint of the reciprocal toothed surfaces to the interface of the attachments 2, 3.

(39) The head 51 provides for an externally knurled ring nut, which defines a tightening knob 54. Internally, separated from the tightening knob by a cavity 56 open in the opposite direction to the stem 50, a coupling profile 53 is adopted, in this particular case a hexagonal recess for hex key.

(40) The connector also provides for a tightening nut 57, adopted to be screwed on the threaded end 55, wrapping the attachments 2, 3 interposed between said elements. Moreover, it is to be noted that, in a variant of the project, the nut can be incorporated into the second attachment 3.

(41) The first attachment 2, individually shown in FIGS. 1-4, is provided with two arms, which we will identify respectively as inner 20 and external 21 ones with respect to the overall structure of the assembled clamp 1. The arms 20, 21 are connected by a C-shaped flexible bridge 22, namely by an elastic hinge that allows the bend thereof outside of a rest configuration of reciprocal parallelism.

(42) The flexible bridge 22 internally has a cylindrical surface, which develops on an arc slightly superior to 180°, to then join the internal planar surfaces of the two arms 20, 21. Such surface defines a bar housing seat 26, inside of which a connecting bar 101 of the external fixator 100 can be clamped.

(43) At the opposite end with respect to the flexible bridge 22, the arms 20, 21 have respective jaws 27a, 27b. Such jaws 27a, 27b, thickened with respect to the rest of the arm, have opposite planar surfaces on which two V-shaped splines are obtained, extended transversally to the attachment. The two splines, faced one another, define a screw housing seat 23 which can contain screws of 4 mm, 5 mm or 6 mm, according to the bend given to the arms by the clamping of the connector 5.

(44) The two arms 20, 21 further comprise respective holes 24, 25 adopted for the passage of the stem 50 of the connector 5. The hole realized on the inner arm 20 is an enlarged hole 24, of oval conformation extended in the sense of extension of the arm, with a substantially greater area with respect to the circumference of the stem 50. On the contrary, the passage hole 25 on the external arm 21 is circular and substantially proportional to the stem 50, still providing for a clearance sufficient to allow the bends of the attachment 2.

(45) Outside of the hole of passage 25 a spherical flaring, namely a convex seat 28 for the concave surface 52 of the connector 5, is realized, which rests on it with substantial contact also in conditions of non-perpendicularity of the external arm 21 with respect to the stem 50.

(46) Last, it is noted that the inner arm 20 is defined, in one of the intermediate portions thereof, by a cylindrical bush 29. Such bush exhibits a radial toothing 29a adopted to be constrained against a corresponding toothing of the juxtaposed attachment, guaranteeing the flexural stability of the clamp 1. Further, on the outer surface rises 29b are provided for, evenly spaced angularly, in the particular case at 90°, which can be used as angular references to guarantee the perpendicularity between connecting bars 101 and screw bones 102.

(47) The second attachment 3, individually shown in FIGS. 5-10, has an analogous structure to that of the first attachment 2, except that it is not provided with jaws that define the seat for the bone screw. It is also provided with two arms, inner 30 and external 31 ones, with respect to the overall structure of the assembled clamp 1, connected to a C-shaped flexible bridge 32.

(48) The flexible bridge 32 defines also in this case a bar housing seat 36, inside of which a connecting bar 101 of the external fixator 100 can be clamped.

(49) The two arms 30, 31 comprise the respective holes 34, 35 adopted for the passage of the stem 50 of the connector 5. The hole realized on the inner arm 30 is an enlarged hole 34 analogous to that obtained on the inner arm 20 of the first attachment 2. The passage hole 35 on the external arm 21 is also here substantially proportional to the stem 50, providing for a clearance sufficient to allow the bends of the attachment 3.

(50) Outside of the passage hole 35 a hexagonal recess 38 is realized for the housing of the clamping nut 57, which, as previously mentioned, can be incorporated in the attachment 3 itself during the printing process.

(51) Also in this case the inner arm 30 is defined, in a terminal and not intermediate portion, by a cylindrical bush 39. Such bush exhibits a radial toothing 39a adopted to be constrained against the toothing of the juxtaposed attachment and rises 39b of reference spaced of 90° one from another.

(52) The spacers 6, individually shown in FIGS. 19-21, are substantially cylindrical sleeves, provided with opposite flanges and lateral flattenings, adopted to ring themselves on the stem 50, separating the arms 20, 21; 30, 31 of a single attachment 2; 3; or, as mentioned above, they can also have a mere centering function, in particular when used in combination with the first attachment 2.

(53) The second variant of clamp 1′, illustrated in FIGS. 29-32, comprises a second attachment 3 of the previously described type and a third attachment 4, held together by a connector 5′.

(54) The third attachment 4, individually illustrated in FIGS. 11 and 12, is composed by two plates 40 substantially counter formed which define to the interface thereof splines and lateral grooves for holding bone screws 102. The splines and/or lateral grooves intersect one another at 90°, and define two pairs of seats for bone screws 102 having different diameter and/or different center to center distance. In particular, in this particular case: in a front-rear direction the plates 40 define two lateral grooves 41 for holding screws of diameter 5 mm or 6 mm, with a center to center distance around the 20 mm; in a right-left direction the plates define two passage holes 42 for holding screws of diameter 4 mm with a center to center distance around the 14 mm.

(55) The connector 5′ for this type of clamp 1′, individually illustrated in FIGS. 16-18, is slightly different with respect to the previously discussed one. In fact, it presents a stem 50′ of an inferior length and a head profile 51′ with only circumferential abutment 52′ to be loaded only on the external part of the third attachment 4 where the profile is realized as a yielding cantilever. In particular, as shown in FIG. 30, such circumferential abutment 52′ does not impinge on the radial toothing of the third attachment 4.

(56) The third variant of clamp 1″, illustrated in FIG. 33, comprises a second attachment 3 and two third attachments 4 overlapped one to another, held together by a connector 5.

(57) Obviously, to the invention described above an expert of the sector, in order to meet temporary and specific needs, can introduce several amendments and variants, all however contained in the field of protection of the invention as defined by the following claims.