Apparatus for treating a fracture

Abstract: Apparatus (10) for fixing a fracture of a bone including an elongated body member (12) having a proximal end (16) and a distal end (18) for insertion into the intramedullary canal of the bone; a tab member (14) having at least one aperture (30) to allow for passage of a screw for fastening of the tab member (14) to the bone; and a bolt (22) for selectively removably coupling the tab member (14) to the proximal end (16) of the body member (12). Preferably, the tab member (14) is of a hollow cylindrical configuration and removably interlocking the first plate member to a second plate member. In another embodiment, the apparatus include a body member for insertion into a bone cavity, the body member having at least one aperture (30) disposed in close proximity to its first end to allow for passage of a screw for fastening the body member (12) to the bone. The present invention is also directed to apparatus (10) for fixing a bone fracture including a first elongated plate member (12) having at least one aperture (64) so as to permit passage of a screw for attachment to the outer surface of a first portion of the bone. The first plate member (62) has a first end (63) and a second end (65) and has a predetermined curvature so as to conform generally to the curvature of the first portion of the bone. The apparatus includes a second elongated plate member (92) having a predetermined curvature so as to conform generally to the curvature of the second portion of the bone. A C-shaped channel is disposed on the first end (63) of the first plate member (62) for selectively removably interlocking the first plate member (62) to the second plate member (92).

Description: The present invention relates to devices and methods for treating a fractured bone. In particular, the present invention is directed to an intramedullary rod directed to the treatment of a bone fracture, for example, in the tibia and humerus, and also to plates for use, for example, on the pelvis, fibula, forearm and distal humerus. The utilization of intramedullary nails or rods in the treatment of bone fractures is well known in the art. Furthermore, a number of prior art intramedullary nail systems comprise intramedullary nails provided with holes therethrough adjacent the proximal and distal ends for insertion of locking screws. Depending upon the severity of the fracture, the intramedullary nail may be implanted without locking screws, with at least one locking screw either proximally or distally (known as either partial or dynamic locking) or with at least one locking screw both proximally and distally (known as either complete or static locking). Static locking neutralizes rotational stresses while preventing shortening of the limb. Dynamic locking neutralizes rotational stresses on one side of the fracture site while permitting axial loading. A static locking condition may be converted into a dynamic locking condition by removing either the proximal or distal screws, thereby permitting axial loading. Both a dynamic locking condition and static locking condition may be converted into an unlocked condition by removing all locking screws, thereby allowing rotational stresses across the fracture site and allowing axial loading of the fracture site. When properly permitted, rotational stresses and axial loading, combined with patient weightbearing, enhances the healing process. However, the removal of the locking screws has the severely adverse effect of permitting the intramedullary nail to migrate or back out of the intramedullary canal. Prior art devices for treating a bone fracture further include plates with holes therethrough for screws to be inserted. These plates are designed to impart compressive forces on the fracture site. A plate, known as a tension band plate, may be applied to one side of the fractured bone with a tension device, and secured with a number of screws which are inserted through the bone and which firmly attach the plate. A tension band plate applies compressive forces to the fracture site and resists rotational stress. In some round bones there is not enough room to apply the tension device. In such instances a semi-tubular plate with oval holes therethrough for screws to be inserted may be utilized. When screwed firmly to the bone, the edges of the semi-tubular plate press into the cortex and resist rotation. When screws are inserted eccentrically at one end of the oval, the plate is placed under tension as the spherical head of the screw engages the plate. Standard size prior art semi-tubular plates, for example, are made with oval holes which accept a single 4.5 mm cortex screw, while small plates accept one 3.5 mm cortex screw. Semi-tubular plates may be bent and twisted so as to fit the fractured bone. If it is necessary to use more than one plate, they can be applied adjacent one another but without any cooperating engagement between them. Further detail review of such prior art devices are presented in the following publications which are incorporated herein: "The Grosse & Kempf™ Intramedullary Nailing System", Howmedica, Inc., 1983 and 1984; Boyle, Marc, M.D., "Howmedica™ Surgical Techniques -- Grosse & Kempf™ Surgical Technique", Howmedica, Inc., 1984; "Russell-Taylor Tibial Interlocking Nail Systems", Richards; "Brooker Tibial System" and "Brooker Tibial Nail Surgical Technique", Biomet Inc.; "Howmedica Quality Systems, The Howmedica ICS™ Stainless Steel Compression Systems", Howmedica, Inc., 1980; Ramon B. Gustilo, M.D. and Michael W. Chapman, M.D., "Orthopedic Surgery Viewpoints '83, Management of Type III Open Fractures", Eli Lilly and Company; "ECT European Compression Technique, Internal Fracture Fixation Reference Manual", Zimmer, Inc.; "Osteo Auto-Compression Plating System Catalog", Richards Medical Company, 1985; "ORIF", DePuy, Inc., 1986; "Introducing Two New Small Bone Sets From Synthes", Synthes Ltd., 1986; and "ASIF Technique", Synthes Ltd. DE-U-7115713 discloses a nail for insertion into a body cavity, the nail comprising a body member having first and second ends, and a tab member which may be coupled to the body member. The present invention is directed to an intramedullary nail comprising a body member for insertion into a bone cavity, the body member having a first end and a second end; a tab member having at least one aperture to allow for passage of a screw for fastening the tab member to the bone; and means for selectively removably coupling the tab member to the first end of the body member. According to one preferred embodiment, the tab member is generally of an annular configuration and has a first end for coupling with the first end of the body member. Its other end is beveled. The one aperture is disposed adjacent the beveled end. Preferably, the tab member has at least one protrusion and the body member has at least one recess configured and dimensioned so as to removably engage the protrusion. Also the body member has a bore at the first end. The bore is configured and dimensioned for engagement with a means for inserting and removing the body member from the bone cavity. This bore is threaded and the coupling means is a bolt disposed on the tab member and being configured and dimensioned for engagement with the bore. Preferably, the tab member and the aperture are configured and dimensioned so as to allow access to the aperture when the body member is disposed in the bone cavity and the tab member is selectively coupled to the body member. The tab member is generally of a hollow cylindrical configuration and has a distal end for coupling with the proximal end of the body member. Also, the tab member has two equally spaced apart protrusions disposed on its distal end and the body member has two equally spaced apart recesses disposed on the proximal end and which are configured and dimensioned so as to removably engage the protrusions respectively. In one preferred embodiment, the body member has a bore at the first end and the bore is configured and dimensioned for engagement with a means for inserting and removing the body member from the intramedullary canal. The bore is threaded and the coupling means is a bolt configured and dimensioned for seating within the hollow cylindrical tab member and for engaging with the bore so as to couple the tab member to the body member. The body member preferably has a first bend adjacent the proximal end of the body member and has a second bend adjacent the distal end of the body member. Also, the body member has at least one aperture generally transversely therethrough disposed between the first bend and the proximal end of the body member. In addition, the body member has at least one aperture generally transversely therethrough disposed between the second bend and the distal end of the body member. At least one ridge is disposed longitudinally along the outer surface of the body member. The body member and tab member are each formed of titanium or a titanium alloy. The body member has an axial passageway and is open ended for selective passage of a guide wire therethrough. The body member also has a beveled portion adjacent its distal end. FIG. 1 is an exploded broken side view illustrating a tibial intramedullary nail, a locking tab member and a driver cavity bolt according to the present invention. FIG. 2 is a partial enlarged side view partially in cross-section of the tibial intramedullary nail, locking tab member, driver cavity and driver cavity bolt as illustrated in FIG. 1. FIG. 3 is a broken cross-sectional side view of the tibial intramedullary nail of FIG. 1 illustrating the driver cavity and interior canal. FIG. 4 is a rear view of the locking tab member of FIG. 1. FIG. 5 is a cross-sectional side view of the locking tab member of FIG. 1. Referring to FIG. 1, a tibial or humeral intramedullary nail 10 according to the present invention is illustrated. The tibial intramedullary nail 10 includes body member 12 for insertion into the intramedullary canal of a tibia for treatment of a fracture of the tibia. Locking tab member 14 which is of a generally annular configuration as shown in FIG. 2 is provided for selectively removable engagement with body member 12. Body member 12 has a first or proximal end 16 and a second or distal end 18. Body member 12 and locking tab member 14 can be selectively coupled by bolt 22 as shown in FIG. 2. As illustrated in FIGS. 1-3, the first or proximal end 16 of body member 12 has a threaded driver cavity or bore 20 into which bolt 22 can be threaded. As shown in FIGS. 2 and 5, the locking tab member 14 has an aperture 24 through which bolt 22 can pass. Tab aperture 24 is configured and dimensioned so as to removably engage bolt 22 so that the locking tab member 14 can be selectively removably attachable to the proximal end 16 of body member 12 as shown in FIG. 2. According to the preferred embodiment, body member 12 has two equally spaced apart recesses 26, which can receive two correspondingly equally spaced apart locking tab protrusions 28 on tab member 14, as illustrated in FIGS. 1 and 3-5. As shown in FIG. 4, locking tab member 14 is provided with two locking tab apertures 30. As illustrated in FIG. 1, locking tab member 14 and locking tab apertures 30 are configured and dimensioned so as to allow for passage of a single straight locking tab screw through either of locking tab apertures 30 to secure the locking tab member to a predetermined portion of the tibia. Locking tab member 14 and locking tab apertures 30 are further configured and dimensioned so as to allow access to either locking tab aperture 30 when the first end 16 and the second end 18 of body member 12 are disposed within the intramedullary canal of the tibia and the locking tab member 14 is engaged with the body member 12. The present invention therefore allows a surgeon to insert a bone screw through either locking tab aperture 30 depending on whether the left or right tibia is fractured without the use of instrumentation and guides which would be necessary to insert a screw through a nonvisible aperture in a portion of body member 12 within the intramedullary canal. Furthermore, no additional incisions are required to insert a bone screw through either locking tab aperture 30 which presents a simple procedure whereby a surgeon can prevent an otherwise unlocked body member 12 from backing out of the intramedullary canal as well as reduce rotational stresses at the fracture site. When locking tab 14 is not attached to body member 12, a driver (not shown) for inserting and removing the body member 12 from the intramedullary canal of the tibia can be utilized. The driver is provided with a first end which is threaded and is configured and dimensioned so as to threadedly engage driver cavity or bore 20 of body member 12. Alternatively, the first end of the driver can be provided with two driver protrusions which are configured and dimensioned so as to removably engage the two recesses 26 provided on first end 16 of body member 12. The body member 12 according to the present invention can be provided in nominal outer diameter sizes ranging from 6 millimeters to 14 millimeters in 1 millimeter increments. The smaller sizes, such as 6 millimeters through 9 millimeters nominal outside diameter, are intended for insertion into a non-reamed intramedullary canal and do not require the use of a guide wire. Larger sizes, such as 10 millimeters through 14 millimeters nominal outside diameter, are intended for insertion into a reamed intramedullary canal and do require the use of a guide wire (not shown). As illustrated in FIG. 3, in the larger sizes the body member 12 is provided with an interior canal or axial passageway 32 having an interior canal entrance 34 located in driver cavity or bore 20 and an interior canal exit 36 located at second end 18 of body member 12. The interior canal accommodates the passage of the guide wire therethrough according to well-known procedures. The body member 12 is provided with a first bend 38 and a second bend 40, as shown in FIG. 1. The first bend 38 is nearer the first end 16 and the second bend 40 is nearer the second end 18. First bend 38 is preferably located approximately 37 mm (1 1/2 inches) to 50 mm (2 inches) from first end 16, and causes the portion of body member 12 from first bend 38 to first end 16 to be bent approximately 15° in the anterior direction when body member 12 is located within the tibial intramedullary canal. Second bend 40 is preferably located approximately 35 mm (1 3/8 inches) to 45 mm (1 13/16 inches from second end 18, and causes the portion of body member 12 from second end 18 to second bend 40 to be bent approximately 6° in the anterior direction when body member 12 is located within the tibial intramedullary canal. The first and second bends 38 and 40 cause a reduction in the pressure applied to the posterior wall of the intramedullary canal when inserting body member 12 therein and facilitate manipulation of body member 12 during such insertion. To further diminish impingement of second end 18 against the posterior wall of the intramedullary canal, body member 12 is provided with a beveled portion 42 adjacent second end 18, as shown in FIG. 1. When body member 12 is provided with an interior canal 32, interior canal exit 36 is located in beveled portion 42, as illustrated in FIG. 3. In the 8 millimeter and 9 millimeter nominal outer diameter sizes, body member 12 is preferably provided with a first proximal aperture 44 located between the first bend 38 and first end 16 and extending in the medial to lateral direction when body member 12 is disposed within the intramedullary canal. In the 10 millimeter nominal outer diameter size and larger sizes, body member 12 is preferably also provided with a second proximal aperture (not shown) located between first bend 38 and first proximal aperture 44 and extending in the anterior to posterior direction. In the 8 millimeter and 9 millimeter nominal outer diameter sizes, body member 12 is preferably also provided with first and second distal apertures 46 located between second bend 40 and second end 18 and extending substantially in the medial to lateral direction when body member 12 is disposed within the intramedullary canal. In the 10 millimeter nominal outer diameter size and larger sizes, body member 12 is preferably also provided with a third distal aperture located between first and second distal apertures 46 and extending in the anterior to posterior direction. As shown in FIG. 1 body member 12 is provided with six ridges 50, each extending from a predetermined location between first proximal aperture 44 and driver cavity 20 to beveled portion 42 at second end 18. The tibial intramedullary nail 10 according to the present invention can be made from any substantially rigid biocompatible material and is preferably made of metal. The preferred material of composition is titanium or a titanium alloy since the pliability of this metal in conjunction with the configuration and dimensions of body member 12 greatly diminish the force exerted on the posterior portions of the tibia by impingement of body member 12 thereon during insertion of body member 12 into the intramedullary canal. According to the present invention, the nail 10 can be secured to the bone by a screw passing through either of apertures 30 in tab member 14 when the body member is positioned in the bone cavity without the need to pass screws through any of nail apertures 44 or 46.

Claims: An intramedullary nail (10) comprising a body member (12) for insertion into a bone cavity, the body member having a first end (16) and a second end (18), and a tab member (14) to be coupled to the body member, characterised in that the tab member (14) has at least one aperture (30) for passage of a screw for fastening the tab member to the bone, and means (22) are provided for selectively removably coupling the tab member (14) to the first end (16) of the body member (12). A nail according to claim 1 characterized in that said tab member (14) is generally of an annular configuration. A nail according to claim 2 characterized in that said tab member (14) has a first end (29) for coupling with said first end (16) of said body member (12) and a second end (31) which is beveled. A nail according to claim 3 characterized in that said at least one aperture (30) is disposed adjacent said second end (31) which is beveled. A nail according to claim 4 characterized in that said tab member (14) has at least one protrusion (28) and said body member (12) has at least one recess (26) configured and dimensioned so as to removably engage said protrusion (28). A nail according to claim 1 characterized in that said body member 12 has a bore 20 at said first end 16. A nail according to claim 6 characterized in that said bore (20) is configured and dimensioned for engagement with a means for inserting and removing said body member (12) from said bone cavity. A nail according to claim 7 characterized in that said bore (20) is threaded and said coupling means (33) is a bolt (22) disposed on said tab member (14) and being configured and dimensioned for engagement with said bore (20) and characterized in that said body member (12) has a first bend (38) adjacent said first end (16) of said body member (12) and a second end (18) of said body member (12).2

Inventors: CHAPMAN MICHAEL W, EDWARDS CHARLES C, MEARS DANA C, CHAPMAN, MICHAEL W., EDWARDS, CHARLES C., MEARS, DANA C.
Applicants: HOWMEDICA, HOWMEDICA INC.
Application year: 1990
Main classification: A61B17
IPC codes: A61B17