Orthopaedic device for the gradual correction of limbs

Abstract: An orthopaedic device for the gradual correction of angular and longitudinal defects of elongated bones, comprising at least one first clamp (3) for a first group of screws insertable in a proximal portion of a bone, and at least one second clamp (5; 40) for a second group of screws insertable in a distal portion of the bone, a longitudinal guide bar (2) positioned externally of the limb to be corrected for slidably supporting said clamps (3; 5; 40); at least one of the clamps is selectively orientatable about a substantially transverse axis for carrying out angular corrections of the bone. There are provided compression/distraction means movably coupleable with said clamps for carrying out longitudinal corrections of the bone. The orientatable clamp (3) has angular adjustment means (14) in a predetermined geometric plane, as well as transverse adjustment means (22) for the group of bone screws (4) carried by said clamp parallel to themselves for compensating the lateral movement induced by the angular correction.

Description: Technical Field The present invention relates to an orthopaedic device for the gradual correction of limbs, in accordance with the preamble of the claim 1. Background Art It is known that external fixation devices, adjustable in length and angular attitude, are commonly utilised for correcting certain angular and longitudinal deformations of long bones of limbs. Such fixation devices essentially comprise clamps which hold groups of bone screws inserted in the portions of the bone affected by defects, such clamps being slidably mounted on elements or guides longitudinally positionable externally to the limb to be treated. The correction is normally carried out gradually with the aid of compressor-distractor devices which act on the mobile clamps while the bone callous regenerates itself permitting its manipulation until the desired correction is obtained. One known device for the gradual correction of the limbs has a lateral clamp which allows an angular correction of the bone. Such known device has the drawback that the angular rotation induces a shifting of the screws in a transverse direction which renders the correction of the limb difficult. Orthopaedic devices according to the preamble of Claim 1 are shown in EP-A-0 699 419 or EP-A-0 385 929. Disclosure of the Invention One principal aim of the present invention is to overcome the above described drawbacks providing an orthopaedic device which allows a complete correction in geometric planes which are also inclined with respect to the lateral and front-rear planes, in a gradual and easily controllable manner. With this principal aim and others in view, there is provided an orthopaedic device for the gradual correction of angular and longitudinal defects of elongated bones, comprising at least one first clamp for a first group of screws insertable in a proximal portion of a bone, and at least one second clamp for a second group of screws insertable in a distal portion of the bone, a longitudinal guide bar positioned externally of the limb to be corrected for slidably supporting said first and second clamps in longitudinally distanced positions, at least one of said clamps being selectively orientatable about a substantially transverse axis for carrying out angular corrections of the bone, there being provided compression/distraction means movably coupleable with said clamps for carrying out longitudinal corrections of the bone, characterised by the fact that said at least one orientatable clamp has angular adjustment means in a predetermined geometric plane, as well as transverse adjustment means for the group of bone screws carried by said clamp parallel to themselves for compensating the lateral movement induced by the angular correction. Brief Description of Drawings The characteristics and advantages of the invention will become apparent from the following description of some preferred but not exclusive embodiments of an intramedullary cavity nail according to the invention, illustrated for illustrative and non-limiting purposes with the help of the attached drawing sheets in which: Fig. 1 illustrates a general front elevation view of the orthopaedic device according to a preferred aspect of the invention applied to a femur in a lateral position; Fig. 2 illustrates a variation of the device of Fig. 1 in enlarged scale and in a correction phase of an angular defect of a femur; Fig. 3 illustrates the device of Fig. 2 at the end of the correction; Fig. 4 illustrates the device of Fig. 1 used in a front-rear plane; Fig. 5 illustrates an enlarged front elevation view of a clamp of the assembly of Fig. 1; Fig. 6 illustrates a lateral elevation view of the detail of Fig. 5; Fig. 7 illustrates a section view of a first variation of the clamp of the assembly of Fig. 1; Fig. 8 illustrates a top plan view of the detail of Fig. 7; Fig. 9 illustrates a lateral elevation view of the detail of Fig. 7; Fig. 10 illustrates a section view of a second variation of the clamp of the assembly of Fig. 1; Fig. 11 illustrates a top plan view of the detail of Fig. 10; Fig. 12 illustrates a lateral elevation view of the detail of Fig. 10; Figs. 13 and 14 illustrate respectively a top plan view and a partially sectional view of a clamp of the device of Figs. 2 and 3. Best Modes for Carrying Out the Invention With reference to the cited figures, an orthopaedic device according to a preferred aspect of the invention, globally indicated by the reference numeral 1, for the gradual correction of angular and longitudinal defects of elongated bones, for example a femur F, essentially comprises a longitudinal guide bar 2 of generally semicircular cross section positioned externally to the limb to be corrected, upon which a first clamp 3 for a first group of screws 4 insertable in a proximal portion of the bone and a second clamp 5 for a second group of screws 6 insertable in a distal portion of the bone are mounted. The proximal clamp 3 comprises an attachment portion 7 movably anchorable to the bar 2, for example by means of a dovetail tenon 8 coupleable to a longitudinal cavity of the bar 2 and a blocking screw 9, upon which is mounted a bracket 10 rotatable about a first substantially longitudinal axis 11. An intermediate body 12 is hinged to the bracket 10 by means of a substantially transversal axis 13 for correcting the angular defects, and is micrometrically adjustable by means of a screw 14 having an end 15 hinged to the body 12, the opposite end 16 being provided with a hexagonal fitting and the central portion being engaged in a pivot member 17 united to the bracket 10. A substantially L-shaped support 18 is rotatably mounted on the intermediate body 12 about a substantially longitudinal second axis 19. The support 18 has two transverse spines 20 which guide a jaw 21 of the clamp and a micrometric screw adjustment mechanism 22 for promoting the controlled translation of the jaw 21 so as to compensate the lateral movements induced by the angular corrections. Fixed on the jaw 21 by means of screws is a jaw 21' of a per se known type. Expediently, there are provided stop screws 23, 24 for blocking the respective axes 11 and 19 so as to define a predetermined geometric plane for the angular correction. The device of Fig. 1 is shown in Fig. 4 but active in a front-rear plane. The second clamp 5, which is normally positioned in a distal or medial position, is of the swivelling type and is formed by a support plate 25 anchorable to the bar 2, upon which is hinged about a substantially longitudinal axis 26 a first jaw 27 of the clamp. A second jaw 28 is locked on the first jaw 26 by means of locking screws 29. Both the jaws have transverse seats of a per se known shape for accommodating the screws 6. The support plate 25 has means for connection to the bar which may be constituted by a dovetail tenon 30 engageable, before the mounting of the other clamp, in a countershaped cavity formed along the bar, and by a stop screw 31 passing through a longitudinal groove of the bar. In the alternative embodiment illustrated in the Figures 10 to 12, the connection means of the plate 25 to the bar 2 are constituted by a connecting block 32 anchored to the bar 2 by means of screws 33, 34 of which one serves to anchor the block allowing it to slide along the groove, while the other serves to block the longitudinal movement of the clamp. The plate has two end supports 35, 36 one of which has an arcuate eyelet hole 37 in which there passes a screw 38 with a hexagonal fitting 39 and also with radial holes 39' for its screwing in case of limited space for the surgeon. Thanks to its possibility of being able to swivel, the clamp 5 may be inclined allowing for the screws to be screwed into the bone also in case of notable curvature of the same, without having to move the clamp excessively towards the end of the bar. Another clamp, referenced by 40, is of an oscillating type, and is constituted by a base 41 anchorable to the bar 2 by means of a screw 42 and having a substantially flat external surface 43. A cover 44 is oscillatingly mounted on the flat base 41 about an axis 45 substantially perpendicular to the longitudinal axis of the bar. To the cover 44 there is fixed by means of a screw 46 a bracket 47 to whose end is hinged an internally threaded ring 48 in which is engaged a screw 49 having an end held axially by a sleeve 50 with a pin insertable in a hole provided in the base 25. The screw 49 has both ends with hexagonal set heads in order to allow to control it from both sides. For blocking the base 41 in the pre-established angular position, there is provided a stop 52 anchored to the base 41 by means of a screw 53 and having a cuneiform end which engages against the bottom of a circular cavity 54 with a bottom substantially countershaped with respect to the stop 52, formed on the external face of said cover. In such a manner it is possible to exert notable blocking forces rendering the orientation of the clamp more reliable and secure. The cover 44 has on its internal face which faces the base 41 five transverse seats 55 for the bone screws, with transverse cross section of greater value than the maximum diameter of the screws and with a V-shaped bottom for permitting the sliding of the screws 56 parallel to themselves in case of loosening of the cover 44. Obviously, all of the clamps have holes for the insertion of controlling ends of compressors/distractors in order to carry out an elongation of the bones.

Claims: Orthopaedic device for the gradual correction of angular and longitudinal defects of elongated bones, comprising at least one first clamp (3) for a first group of screws insertable in a proximal portion of a bone, and at least one second clamp (5; 40) for a second group of screws insertable in a distal portion of the bone, a longitudinal guide bar (2) positioned externally of the limb to be corrected for slidably supporting said clamps (3; 5; 40) in longitudinally distanced positions, at least one of said clamps being selectively orientatable about a substantially transverse axis for carrying out angular corrections of the bone, there being provided compression/distraction means movably coupleable with said clamps for carrying out longitudinal corrections of the bone, characterised by the fact that said at least one orientatable clamp (3) has angular adjustment means (14) in a predetermined geometric plane, as well as transverse adjustment means (22) for the group of bone screws (4) carried by said clamp parallel to themselves for compensating the lateral movement induced by the angular correction. Orthopaedic device according to claim 1, wherein said angular (14) and transverse (22) adjustment means are of a micrometric type. Orthopaedic device according to claim 1, wherein said at least one orientatable clamp (3) has axial orientation means (11; 19) for selectively defining said angular adjustable geometric plane. Orthopaedic device according to claim 1, wherein said at least one orientatable clamp (3) comprises an attachment portion (8) movably anchorable to said longitudinal bar (2) upon which there is mounted a bracket (10) pivotable about a substantially longitudinal first axis (11). Orthopaedic device according to claim 1, wherein on said bracket (10) there is hinged about a substantially transverse axis (13) an intermediate body (12) united to said bracket by means of a screw and female thread micrometric adjusting mechanism (14). Orthopaedic device according to claim 1, wherein on said intermediate body (12) there is mounted a substantially L-shaped support (18) rotatable about a substantially longitudinal second axis (19). Orthopaedic device according to claim 1, wherein said support (18) has transverse guiding means (20) for a jaw (21) of said clamp and a screw and female thread micrometric adjustment mechanism (22) for promoting the controlled translation of said jaw (21) along said transverse guiding means. Orthopaedic device according to claim 1, wherein there are provided stop means (23, 24) for each of said substantially longitudinal rotation axes for selectively determining the angular adjustment plane of the clamp. Orthopaedic device according to claim 1, wherein the other one of said clamps (40) is of the oscillating type and has a base (41) anchorable to said bar (2) with a substantially flat external surface (43). Orthopaedic device according to claim 1, wherein on said base (41) there is mounted a cover (44) oscillable about an axis (45) substantially perpendicular to the longitudinal axis of said bar. Orthopaedic device according to claim 1, wherein there are provided screw and female thread adjustment means (49) adapted to selectively control the angular position of said cover (44) with respect to said base (41), with said screw (49) provided with holding means towards both its longitudinal ends. Orthopaedic device according to claim 1, wherein there is provided a cuneiform stop (52) screwable to said base for selectively engaging on the bottom of a circular seat (54) with a bottom substantially countershaped with respect to the stop formed on the external face of said cover (44). Orthopaedic device according to claim 1, wherein said cover has on the internal face which faces said base a plurality of transverse seats (55) for the bone screws, with transverse sections of greater size than the maximum diameter of the screws and with a V-shaped bottom for allowing the screws to slide parallel to themselves in case of loosening of the cover. Orthopaedic device according to claim 1, wherein there is provided a further clamp (5) for locking a group of screws (6) insertable in medial and distal portions of the bone. Orthopaedic device according to claim 14, wherein said medial clamp (5) is of the basculant type, and is formed by a support plate (25) anchorable to said bar to which is hinged with a substantially longitudinal axis (26) a first jaw (27) of said clamp to which is coupleable a second jaw (28) by means of locking screws (29). Orthopaedic device according to claim 15, wherein said support plate (25) has means for connecting to said bar constituted by a dovetail tenon (30) engageable, before the mounting of the other clamps, in a countershaped seat formed along said bar and by a stop screw (31) passing through a longitudinal groove of said bar. Orthopaedic device according to claim 15, wherein said support plate (25) has means for connecting to said bar (2) constituted by a connection block (32) screwed to said plate for blocking the separation of the bar (2) also after the mounting of the other clamps.

Inventors: FACCIOLI GIOVANNI, TEN VELDHUIS SANDER, VENTURINI DANIELE, FACCIOLI, GIOVANNI, TEN VELDHUIS, SANDER, VENTURINI, DANIELE
Applicants: ORTHOFIX SRL, ORTHOFIX S.R.L.
Application year: 1997
Main classification: A61B17
IPC codes: A61B17