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Publication numberUS20050075637 A1
Publication typeApplication
Application numberUS 10/816,674
Publication dateApr 7, 2005
Filing dateApr 2, 2004
Priority dateApr 4, 2003
Also published asUS7621913, US20070260247
Publication number10816674, 816674, US 2005/0075637 A1, US 2005/075637 A1, US 20050075637 A1, US 20050075637A1, US 2005075637 A1, US 2005075637A1, US-A1-20050075637, US-A1-2005075637, US2005/0075637A1, US2005/075637A1, US20050075637 A1, US20050075637A1, US2005075637 A1, US2005075637A1
InventorsElliot Semet
Original AssigneeSemet Elliot Charles
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Interlocking IM nails with outer screw
US 20050075637 A1
Abstract
This invention is a mechanism and design that uses headless screws that interlock with the Intramedullary Nail. Canulated outer screws engage the threads of the headless screws and further locks into the Intramedullary Nail. A sleeve on the outer end of the headless screw will aid in centering of the IM Nail. This process may be repeated contra laterally for optimal fixation and centering of the IM Nail when allowed by the anatomy. This mechanism ensures no play in the screw-nail interface which is inherent in current interlocking designs.
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Claims(1)
1. A mechanism to secure Intramedullary Nails by using headless screws to interlock with the Intramedullary Nail with a canulated outer screw that engages the headless screw's threads and further locks onto the Intramedullary Nail. This process may be repeated contra laterally. This mechanism immobilizes the Intramedullary Nail to maintain fracture reduction and aids in centering of the IM Nail.
Description
    CROSS REFERENCE TO RELATED APPLICATIONS
  • [0001]
    Provisional Patent Application No.: 60/459,952 with a filing date of Apr. 4, 2003 (submitted by inventor of this application)
  • [0002]
    U.S. Pat. No. 6,019,761, dated Feb. 1, 2000 suggests interlocking by using guidewire that goes in through the IM Nail holes, up or down the IM Nail and out the next hole.
  • [0003]
    U.S. Pat. No. 6,524,314, dated Feb. 25, 2003 suggests interlocking by using 2 lag screws and a locking screw through the IM Nail.
  • [0004]
    An Intramedullary Nail (IM Nail) is inserted into the cortical bone. Standard interlocking technique is used to place each of the screws into the nail. However, these screws are headless (versus a headed screw used in current techniques). The screwdriver for placing the headless screw remains attached to this headless screw after insertion. A decision is made on the length of the outer screw (the one that encapsulates the headless screw) to be placed so that the intramedullary nail is kept at a fixed distance from the cortex of the bone.
  • [0005]
    The headless screw is then over drilled with a canulated drill. The canulated outer screw is then placed over the modular screwdriver and then over the headless screw. The outer screw engages threads on the nail, locking the outer screw to the nail. The opening of the nail may be tapered such that it allows the outer screw a perpendicular insertion to the nail. The screw may also be tapered to all interlock with the IM Nail.
  • [0006]
    Additionally, a small thin sleeve may be on the outer screw that will allow for centering the headless screw in the nail opening. This will eliminate the play of the headless screw within the nail. Upon surgeon's discretion, a similar outer screw can be placed from the contra lateral side where the anatomy will allow it. Having screws on opposing sides of the IM Nail, will help to center the nail and guarantee locking and increases cortical purchase of the screws.
  • STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
  • [0007]
    Not Applicable
  • REFERENCE TO SEQUENCE LISTING
  • [0008]
    Not Applicable
  • BACKGROUND OF THE INVENTION
  • [0009]
    The current methods of fracture reduction are:
      • Casts/braces
      • Plates:
        • Conventional
        • Locking
      • External fixation
      • Intramedullary Nails
  • [0016]
    Intramedullary Nails have several advantages over other forms of fixation:
      • they are less invasive than plates;
      • they have a lower infection rate;
      • nails are stronger than the plates;
      • nails have a mechanical advantage compared to plates;
      • the screws used with nails are more resistant to breakage due to the decreased moment arm;
      • screws may be placed in different planes;
      • nails have a high rate of union;
      • nails allow for anatomic reduction;
      • cast/braces immobilize the limb and do not allow early motion;
      • external fixators have a risk of pin tract infections.
  • [0027]
    One of the current method of interlocking IM Nails is to solely use screws, which can result in loss of reduction because of the inherent play in screw-nail interface. A second way of interlocking IM Nails is to cap the screw at the contra lateral cortex, which increases fixation in the cortical bone; however, does not help the screw-nail interface; additionally, pressure applied by the capping on one end may cause the distal end to move out of position. A third available way of interlocking IM Nails is to have the hole of the IM Nail lined with rubber to provide a more grippable material for the screws; however, the inherent play in rubber does not provide sufficient locking. The rubber line IM Nails also have the possible for foreign body reactions with flaking of the rubber.
  • [0028]
    This new design, with threaded guidewire in between the screws, locks the screw in place to eliminate this play and result in a more stable form of fixation.
  • [0029]
    Two other patented ways of interlocking IM Nails were found, however, neither are currently marketed:
      • An interlocking Intramedullary Nail (U.S. Pat. No. 6,524,314, granted Feb. 25, 2003) provides for a different mechanism, using 2 lag screws and a locking screw. This product is currently not marketed; however, this would be a difficult mechanism because there are only a couple of safe zones where screws can be placed. With the addition of 2 screws placed for fixation, it may be difficult to find safe zones. Additionally, the may cross thread early prohibiting further insertion.
      • An interlocking Intramedullary Nail (U.S. Pat. No. 6,019,761, granted Feb. 1, 2000) provides for interlocking by placing a guidewire through one screw hole up to and out of the next. This patent also relies on drilling holes versus already manufactured holes and dropping wires through the holes and using the screws to cause the wires to interlock to the screws. This patent has a complete different means by which the interlocking would occur and be enhanced.
  • [0032]
    This new mechanism, with the headless screw and outer screw, locks the screw in place to eliminate this play and result in a more stable form of fixation. A sleeve on the outer end of the screw will aid in centering of the screw. Additionally, the option of placing an outer screw on both sides of the IM Nail offers a possibly stronger fixation with increased ability to center the IM Nail.
  • BRIEF SUMMARY OF THE INVENTION
  • [0033]
    This invention provides for a new method for locking Intramedullary Nails (IM Nails) with headless screws for performing interlocking with the IM Nail. The headless screw is over drilled with a canulated drill. A subsequent, outer screw is placed such that it encapsulates this headless screw. The outer screw engages threads on the nail, locking the outer screw to the nail. This method and design eliminates play in the screw-nail interface and result in a more stable form of fixation. The headless screw may also have a sleeve on the outer end which will aid in centering of the IM Nail. The outer screw may also be placed from the contra lateral side where the anatomy will allow it.
  • BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
  • [0034]
    Page 1: Diagram of Insertion of the first headless screw into Intramedullary nail
      • 1.Cortical bone
      • 2.Intramedullary Nail
      • 3.Headless screw
      • 4.Modulated screwdriver
  • [0039]
    Page 2: Diagram of over drilling around the headless screw with canulated drill.
      • 1.Headless screw
      • 2.Modulated screwdriver
      • 3.Are of over drilling around headless screw
      • 4.Intramedullary Nail
  • [0044]
    Page 3: Diagram of insertion and interlocking of outer screw to inner screw and Intramedullary Nail
      • 1.Canulated outer screw
      • 2.Optional sleeve with variable length
      • 3.Dotted line showing canulated outer screw to be placed over headless screw
      • 4.Engaged outer screw over headless screw
      • 5.Place where outer screw interlocks with Intramedullary Nail
      • 6.Intramedullary Nail
      • 7.Placement of additional optional outer screw on the contra lateral side
  • DETAILED DESCRIPTION OF THE INVENTION
  • [0052]
    The IM Nails and screws are manufactured with cobalt-chrome, titanium or other materials for strength and durability. The current methods do not address screw-nail interface locking and can cause loss in reduction. In this invention, the IM Nail is secured by headless screws and canulated outer screws that cap the headless screws; this will secure and eliminate movement of the screws to the IM Nail.
  • [0053]
    The screwdriver for placing the headless screw remains attached to this headless screw after insertion. A decision is made on the length of the outer screw (the one that encapsulates the headless screw) to be placed so that the intramedullary nail is kept at a fixed distance from the cortex of the bone. The headless screw is then over drilled with a canulated drill. The outer screw is then placed over the modular screwdriver and then over the headless screw. The outer screw engages threads on the nail, locking the outer screw to the nail. The opening of the nail may be tapered such that it allows the outer screw a perpendicular insertion to the nail. The screw may also be tapered such that it can also interlock with the IM Nail.
  • [0054]
    Additionally, a small thin sleeve may be on the outer screw that will allow for centering the headless screw in the nail opening. This will eliminate the play of the headless screw within the nail. Upon surgeon's discretion, a similar outer screw can be placed from the contra lateral side where the anatomy will allow it.
  • [0055]
    Current methods of interlocking IM Nails do not eliminate the screw-nail interface play. Therefore, current methods can result in loss of reduction of the fracture. This method and design in locking eliminates play in the screw-nail interface and results in a more stable form of fixation.
Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US4467794 *Feb 8, 1982Aug 28, 1984Ernest MaffeiIntramedulary bone-setting assembly
US5769852 *May 10, 1996Jun 23, 1998Medevelop AbImplantable anchoring element and anchoring assembly for prostheses
US6126662 *Nov 25, 1998Oct 3, 2000Carmichael; Robert P.Bone implant
US6736818 *May 10, 2002May 18, 2004Synthes (U.S.A.)Radially expandable intramedullary nail
US20030040747 *Aug 24, 2001Feb 27, 2003Dean John C.Interlocking intramedullary nail
US20040127898 *Oct 9, 2003Jul 1, 2004Michael AdamBone fixing system
US20040147930 *Dec 15, 2003Jul 29, 2004Nils ZanderOsteosynthetic aid
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US8128627Dec 29, 2008Mar 6, 2012Sonoma Orthopedic Products, Inc.Segmented intramedullary system and apparatus
US8287540Jun 18, 2010Oct 16, 2012Kettering UniversityEasily implantable and stable nail-fastener for skeletal fixation and method
US8430879Apr 30, 2013Sonoma Orthopedic Products, Inc.Segmented intramedullary structure
US8496658Sep 11, 2012Jul 30, 2013Sonoma Orthopedic Products, Inc.Segmented intramedullary structure
US8652136Aug 15, 2011Feb 18, 2014Zimmer, GmbhFemoral fracture fixation device
US8668695Oct 13, 2009Mar 11, 2014Zimmer GmbhIntramedullary nail
US8771272Sep 24, 2012Jul 8, 2014Kettering UniversityEasily implantable and stable nail-fastener for skeletal fixation and method
US20080287951 *Mar 21, 2008Nov 20, 2008Stoneburner James DSegmented intramedullary structure
US20090157079 *Feb 19, 2009Jun 18, 2009Wright Medical Technology, Inc.Intramedullary fixation assembly and devices and methods for installing the same
US20090228007 *Dec 29, 2008Sep 10, 2009Osteolign, Inc.Segmented intramedullary system and methods
US20090228008 *Dec 29, 2008Sep 10, 2009Osteolign, Inc.Segmented intramedullary system and apparatus
WO2011159902A2 *Jun 16, 2011Dec 22, 2011Kettering UniverisityAn easily implantable and stable nail-fastener for skeletal fixation and method
WO2011159902A3 *Jun 16, 2011Apr 5, 2012Kettering UniverisityAn easily implantable and stable nail-fastener for skeletal fixation and method
Classifications
U.S. Classification606/304, 606/321, 606/64, 606/328
International ClassificationA61B17/72
Cooperative ClassificationA61B17/725, A61B17/72
European ClassificationA61B17/72, A61B17/72E4