The present invention relates generally to the field of orthopaedic trauma, and more particularly to a device for positioning in the medullary canal of a long bone.
The skeletal system includes many long bones that extend from the human torso. These long bones include the femur, fibula, tibia, humerus, radius and ulna. These long bones are particularly exposed to trauma from accidents, and, as such, may be fractured during a trauma. Automobile accidents, for instance, are a common cause of trauma to long bones. In particular, the femur and tibia frequently fracture when the area around the knee is subjected to a frontal automobile accident.
Often the distal end or proximal portions of the long bone, for example the femur and the tibia, are fractured into several components and must be realigned. Mechanical devices, commonly in the forms of pins, plates, screws, nails, wires and external devices are commonly used to attach fractured long bones. The pins, plates, wires, nails and screws are typically made of a durable material compatible to the human body, for example titanium, stainless steel or cobalt chromium.
Subtrochanteric and femoral shaft fractures have been treated with the help of intramedullary rods or nails, which are inserted into the marrow canal of the femur to immobilize the femur parts involved in fractures.
As shown in
Referring now to
Intramedullary nails typically have a generally cylindrical cross section and may be cannulated. The intramedullary canals of long bones of humans such as femurs have a shape that varies from person to person. The intramedullary canals of femurs have an arc or bow in the anterior posterior plane. Intramedullary nails, such as femoral nails, are available with a bowed shape based on anatomical statistics to account for the bow of the human intramedullary canal. Femoral nails are typically inserted in the bone through the proximal epiphysis of the long bone, with the entry point positioned either centrally, through the piriformis fossa, or on a side, through the greater trochanter. Femoral nails are typically either in the form of a piriformis fossa nail, with a generally linear proximal end portion for insertion through the piriformis fossa, or in the form of a greater trochanter nail, with a generally curved proximal end portion for insertion through the greater trochanter. The linear proximal end portions and the curved proximal end portions that are shaped to account for the insertion of the nail in the piriformis fossa and the greater trochanter, respectively, compromise the otherwise anatomical shape of the nail when fully inserted and often result in an improper fit. As a result, in spite of efforts to provide an anatomical intramedullary nail, anatomical differences from patient to patient result in nails often failing to fit properly in the canal. If a nail does not match the human bone canal, the nail may impart thigh pain while the implant is in the human bone canal. Further, each of these two separate nail configurations needs to be manufactured and made available for surgeries. Therefore, it would be advantageous to provide a nail that could be easily modified to fit the patient.
According to one embodiment of the present disclosure, there is provided an intramedullary nail for use in a medullary canal of an epiphysis and a diaphysis of a long bone. The nail includes a body having a length in a longitudinal direction and a width in the transverse direction normal to the longitudinal direction. The body has a diaphyseal portion and a first epiphyseal portion. The diaphyseal portion has an external periphery configured for placement in the medullary canal of the diaphysis of the long bone. The diaphyseal portion defines a longitudinally extending first surface of the diaphyseal portion. The first surface defines a longitudinally extending first void. The first epiphyseal portion extends from the diaphyseal portion. The first epiphyseal portion is configured for placement in the medullary canal of the first epiphysis of the long bone. The nail also includes a first insert positioned in the longitudinally extending first void of the diaphyseal portion. The first insert and the diaphyseal portion of the body are made from different materials.
According to an aspect of an embodiment of the disclosure, the first void of the diaphyseal portion of the body may include a slot, an aperture or a groove. According to yet another aspect of an embodiment of the disclosure, the diaphyseal portion of the body is made of a first material and the first insert is made of a second material. The first material has a modulus of elasticity greater than the modulus of elasticity of the second material.
According to another embodiment of the present disclosure there is provided an intramedullary nail for use in a medullary canal of a long bone. The nail defines a body having a length in a longitudinal direction and a width in the transverse direction normal to the longitudinal direction. The body defines a longitudinally extending first void that does not penetrate the body in the transverse direction.
According to yet another embodiment of the present disclosure there is provided an intramedullary nail for use in a medullary canal of a long bone. The intramedullary nail includes a nail having a length in a longitudinal direction and a width in a transverse direction normal to the longitudinal direction. The nail is made of a first material and defines a longitudinally extending first void that does not penetrate the nail in the transverse direction. The intramedullary nail also includes a first insert made of a second material and configured for placement in the longitudinally extending void of the nail. The first material has a modulus of elasticity greater than the modulus of elasticity of the second material.
According to yet another embodiment of the present disclosure there is provided a method for performing trauma surgery on a long bone. The method includes the step of providing an intramedullary nail. The nail includes a body having a diaphyseal portion and an epiphyseal portion. The diaphyseal portion has a diaphyseal portion length in a longitudinal direction and a diaphyseal portion width in a transverse direction normal to the longitudinal direction. The diaphyseal portion defines a longitudinally extending void of the diaphyseal portion of the nail. The method also includes the step of providing a first insert made of a second material. The first material has a modulus of elasticity greater than the modulus of elasticity of the second material. The method further includes the step of positioning the first insert in the longitudinally extending void of the diaphyseal portion of the nail. The method also includes the step of positioning the nail in the medullary canal.
Technical advantages of the present invention will be readily apparent to one skilled in the art from the following figures, descriptions and claims.
Corresponding reference characters indicate corresponding parts throughout the several views. Like reference characters tend to indicate like parts throughout the several views.
Embodiments of the present invention and the advantages thereof are best understood by referring to the following descriptions and drawings, wherein like numerals are used for like and corresponding parts of the drawings.
According to the present disclosure and referring now to
While the body 106 may have any suitable shape, typically the body 106 has a shape that conforms to the medullary canal 22 of the femur 20. Since the shape of the medullary canal 22 is generally cylindrical and arcuate, the body 106 of the nail 100 typically has a generally cylindrical cross section and has an arcuate shape to match that of the canal 22.
The body 106 includes a central or diaphyseal portion 112. The diaphyseal portion 112 includes an external periphery 114 configured for placement in the medullary canal 22 of diaphysis 24 of the femur 20. The diaphyseal portion 112 defines the longitudinally extending first void 108. The diaphyseal portion 112 as shown in
The body 106 also includes a first or proximal epiphyseal portion 122 extending from the diaphyseal portion 112. The proximal epiphyseal portion 122 includes a proximal end 130 of the body 106 of the intramedullary nail 100. The proximal epiphyseal portion 122 is configured for placement in the medullary canal 22 of the proximal epiphysis 26 of the femur 20. Since the femur 20 includes a proximal metaphysis 30 positioned between the diaphysis 24 and the proximal epiphysis 26, a part of the diaphyseal portion 112 or a part of the proximal epiphyseal portion 122 of the body 106 of the nail 100, or both, passes through the proximal metaphysis 30 of the femur 20.
The proximal epiphyseal portion 122 may as shown have the same arcuate, cylindrical shape as the diaphyseal portion 112. Alternatively, the proximal epiphyseal portion may be straight and may have an irregular shape or a larger periphery than the diaphyseal portion of the nail. The proximal epiphyseal portion 122 of the nail 100 typically includes features for receiving fasteners to axially secure the nail 100 to the femur 20.
As shown in
Referring again to
It should be appreciated that the intramedullary nail 100 may include only the diaphyseal portion 112 and the proximal epiphyseal portion 122. The intramedullary nail 100 may, however, as is shown in
The distal epiphyseal portion 132 of the nail 100 is positioned in the distal epiphysis 28 of the femur 20. Since the distal metaphysis 32 of the femur 20 is positioned between the distal epiphysis 28 and the diaphysis 24, a part of the diaphyseal portion 112 or a part of the distal epiphyseal portion 132 of the body 106 of the nail 100, or both, passes through the distal metaphysis 32 of the femur 20.
The distal epiphyseal portion 132 typically includes features for securing the nail 100 to the femur 20 in the form of, for example, a first distal opening 150 extending transverse or normal to the longitudinal axis 138 of the nail 100. The distal epiphyseal portion 132 further includes a second distal opening 152 extending proximally from the first distal opening 150. The second distal opening 152 may similarly be transverse or normal to the longitudinal axis 138 of the nail 100. The first cortical screws 142 are fitted in the openings 150 and 152 and are secured to first cortical wall 44 and second cortical wall 46 of the femur 20. The distal epiphyseal portion 132 may further include additional openings 154 positioned normal to the first distal opening 150 and the second distal opening 152, as well as, normal to the longitudinal axis 138 of the nail 100. The first cortical screws 142 may similarly be fitted into the additional openings 154 in the distal epiphyseal portion 132 of the nail 100.
Referring now to
The diaphyseal portion 112 is arcuate and is defined by a radius RN extending from origin 156, as shown in
While the first void may have any suitable shape, as shown in
While the nail of the present disclosure may be utilized with a solitary void or channel, it should be appreciated that a second void 162, as shown in
The voids 108 and 162 may be positioned anywhere around the periphery of the body 106 of the nail 100. To provide additional flexibility in the anterior posterior plane to permit the nail to match the arcuate shape of the canal 22 of the femur 20 in the anterior posterior plane, the voids 108 and 162 are oriented relative to medial/lateral plane 186.
Referring again to
The diaphyseal portion 112 of the body 106 of the nail 100 has a length DL that is greater than length PEL of the proximal epiphyseal portion 122 of the body 106 of the nail 100 or length DEL of the distal epiphyseal portion 132 of the body 106 of the nail 100. For example length DL of the diaphyseal portion 112 may be at least twice as great as the length PEL of the proximal epiphyseal portion 122 or the length DEL of the distal epiphyseal portion 132. For example length DL of the diaphyseal portion 112 may be at least three times as great as the length PEL of the proximal epiphyseal portion 122 or the length DEL of the distal epiphyseal portion 132.
The body 106 of the nail 100, as shown, is integral with the diaphyseal portion 112 and the epiphyseal portions 122 and 132 being made of the same material. The diaphyseal portion 112 may be made of any suitable durable material and may for example be made of a metal. The diaphyseal portion 112 should be a material compatible with the human anatomy. The diaphyseal portion 112, if made of a metal, may be made of, for example, a cobalt chromium alloy, a stainless steel alloy, or a titanium alloy.
With continued reference to
The inserts 110 and 170 may be fitted into the voids 108 and 162, respectively, in any suitable manner. For example and as shown in
Alternatively, the first insert 110 and the second insert 170 may be secured to the voids 108 and 162 by an adhesive, for example, glue. Alternatively, it should be appreciated that fasteners such as screws (not shown) may be utilized to secure the inserts 110 and 170 into voids 108 and 162 of the diaphyseal portion 112 of the body 106 of the nail 100.
Alternatively, it should be appreciated that the first insert 110 and the second insert 170 may flow into the voids 108 and 162, respectively, of the nail 110 in a liquid or molten state. Features may be provided in the surfaces of body 106 to secure the inserts 110 and 170 after the liquid material solidifies. The first insert 110 and the second insert 170 may be molded into the first void 108 and the second void 162 in any suitable fashion. For example, the first insert 110 and the second insert 170 may be molded onto the nail 110 as a procedure during the manufacturing of the nail 110 or may be placed onto the nail 110 in the operating room based upon patient's specific information.
The nail 100 may as shown in
The first insert 110 and the second insert 170 may be made of any suitable durable material compatible with the human anatomy and is typically made of a material having a rigidity which is less than the rigidity of the material of which the diaphyseal portion 112 of the body 106 of the nail 100 is made.
While many measurements of rigidity may be made. For simplicity for the materials utilized in this device the measurement of Modulus of Elasticity may be used. The Definition of Modulus of Elasticity is the ratio of stress (nominal) to corresponding strain below the proportional limit of a material. It is expressed in force per unit area, usually pounds per square inch or kilograms-force per square centimeter. For example, the first insert 110 and the second insert 170 may be made of a material having a modulus of elasticity which is less than the modulus elasticity of the diaphyseal portion 112. For example, the first insert 110 and the second insert 170 may be made of a polymer, for example polyethylene, for example ultra high molecular weight polyethylene, for example MARATHON® Cross-linked Polyethylene, sold by DePuy Orthopaedics, Inc., Warsaw, Ind.
As shown in
It should be appreciated that the first void 108 and the second void 162 should be sized such that the lands 166 and the web 168, in combination with the selection of the materials for the body 106 and the inserts 110 and 170, provide the nail 100 with the desired rigidity so that the nail 100 may be easily inserted through either the piriformis fossa or the greater trochanter.
When utilizing the composite flexible intramedullary nail of the present disclosure it may be desirable to provide rigidity to the nail that mimics or replicates the rigidity of the patient's bone. Thus, specific patient information, such as age, weight, and activity, as well as patient's specific bone geometry, may be utilized to obtain the desired rigidity of the nail 100. For example, X-Ray films or CAT scans may be taken of the patient's bone to ascertain the size of the bone and the thicknesses of the cortical walls to determine the rigidity of the patient's bone. Based on this information, the materials and shape of the nail 100 and the inserts 110 and 170 may be determined to obtain a nail with a rigidity matching that of the patient's bone.
To provide matching nails for a wide variety of patients, a kit 180 as shown in
According to the present disclosure and referring now to
The method 200 further includes a step 212 of providing a first insert. The first insert is made of a second material and is positionable in the longitudinally extending void of the diaphyseal portion of the nail. The first material has a modulus of elasticity greater than the modulus of elasticity of the second material. The method 200 further includes a step 214 of positioning the insert in the void of the nail. The method 200 further includes a step 216 of positioning the nail in the medullary canal.
The method 200 may further include a step of providing a second insert made of a third material and configured for removable placement in the longitudinally extending void of the diaphyseal portion of the nail. The third material has a modulus of elasticity different from the modulus elasticity of the second material. The step of positioning the insert in the void of the nail 214 includes the steps of selecting one of the first insert and the second insert based on patient's specific information and positioning the selected one of the first insert and the second insert in the void of the nail. Thus, the surgeon may intraoperatively or preoperatively examine the patient and make measurements, observations, performs tests, and take data of the patient. The information obtained may include the patient's activity level, age, general health, weight and the specific characteristics of the patient's bone into which the nail is to be placed. The specific characteristics may include the overall size of the bone, the thickness of the cortical wall, and the density of the cancellous portion of the bone. The surgeon may then select the first insert or the second insert in order to build a nail that matches the rigidity of the patient's bone. The inserts, when used with the nail kit 180 of
The method 200 may further include a step of preparing a cavity in the medullary canal of the diaphysis of a long bone through a selected one of the piriformis fossa or the greater trochanter of the first epiphysis of the long bone. The surgeon may make his selection based upon the condition of the bone and/or his preference. The surgeon may utilize the intramedullary nail of the present disclosure and selectively prepare the cavity through the piriformis fossa or the greater trochanter and utilize the same nail. This is possible because of the added flexibility of the flexible composite nail of the disclosure. The step of positioning the nail in the medullary canal may include the step of inserting the nail through the selected one of the piriformis fossa or the greater trochanter.
While it should be appreciated that the nail of the present disclosure may include the pair of spaced apart voids or channels as shown in
The void 308 may have any suitable shape and, as shown in
The body 306 includes the diaphyseal portion 312 as well as the proximal epiphyseal portion 322 and the distal epiphyseal portion 332 and is shown with a unitary construction. Alternatively, the body 306 may be modular. The proximal epiphyseal portion 322 includes a first proximal opening 336 and a second proximal opening 340 spaced from the first proximal opening 336. The proximal openings 336 and 340 each receive a cortical bone screw 342 as shown in phantom. The proximal epiphyseal portion 322 further includes a proximal slot 344 for receiving a cancellous bone screw 346 as shown in phantom.
The distal epiphyseal portion 332 may include a first distal opening 350 and a spaced apart second distal opening 352. The distal openings 350 and 352 may be adapted to receiving the cortical bone screws 342. The distal epiphyseal portion 332 may further include additional transverse distal openings 354 spaced from the first distal opening 350 and the second distal opening 352. The additional distal openings 354 may be adapted for receiving the cortical screws 342.
Nail 300 further includes a first insert 310 that matingly fits in the longitudinally extending void 308. The first insert 310 has a size and shape that matingly fits in the void 308. The first insert 310 may be secured in the void 308 in any suitable fashion. For example, the first insert 310 may be interferencely fitted into the void 308 or the void 308 may be placed in a fluid or liquid state into the void 308 and secured by solidifying in the void 308. The diaphyseal portion 312 of the body 306 of the nail 300 may include a feature in the form of a notch 372 into which a protrusion 374 formed on the first insert 310 matingly fits.
The first insert 310 may be placed into the void 308 of the body 306 of the nail 300 preoperatively or intraoperatively. For example, the nail 300 may be provided with insert in tact upon receipt at the hospital. Alternatively, a variety of inserts each having different rigidities may be available for the surgeon to place in the body 306 of nail 300 in the operating room upon selection by the surgeon of the proper insert. Alternatively, the first insert 310 may positioned intraoperatively. If inserted intraoperatively, the first insert 310 may be positioned in the void 308 by inserting the insert 310 in a liquid form through longitudinal opening 378 in the body 306 of the nail 300.
Referring now to
The nail 400 further includes an insert 410 which is fitted in the void 408. The insert 410 has a generally circular cross section and is matingly fitted to fill the void 408 defined by void diameter VD. The insert 410 is inserted at proximal end 430 of the nail 400 into void 408. It should be appreciated that the insert 410 may be inserted in the nail through the proximal end 430 during manufacture, in the operating room, or intraoperatively, with the body 406 of the nail 400 inserted into the femur 20 of the patient prior to placing the insert 410 into the body 406. The insert 410 may be positioned or placed in a solid condition through the void 408 or may be placed as a liquid into the void 408. It should be appreciated that the insert 410 may be secured to the body 406 by a protrusion 474 that fits into a notch 472 formed in the diaphyseal portion 410 of the body 406 of the nail 400, by an interference fit, by fasteners, or by glue.
The proximal epiphyseal portion 422 of the body 406 of the nail 400 may further include proximal openings 436 and 440 for receiving cortical screws 442, as well as a proximal slot 444 for receiving a cancellous bone screw 446. The distal epiphyseal portion 432 of the body 406 of the nail 400 may include distal openings 450, 452 and 454 for receiving the cortical bone screws 442.
It should be appreciated that the void of the present disclosure may include void portions of various shapes or configurations. For example the void may include a slot portion, a groove portion and an aperture portion, or any combination of these portions. Alternatively a nail may include separate voids of various types including a slot, a groove and an aperture or any combination of these voids. Such nails may include insert that conform to the shapes of the respective slots, grooves and apertures or portion of slots, grooves and apertures.
Of course, numerous other adaptations are possible. Moreover, there are advantages to individual advancements described herein that may be obtained without incorporating other aspects described above. Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred embodiments contained herein.
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