CA2042642A1 - Prosthetic intramedullary femoral prosthesis with preformed sheath - Google Patents
Prosthetic intramedullary femoral prosthesis with preformed sheathInfo
- Publication number
- CA2042642A1 CA2042642A1 CA002042642A CA2042642A CA2042642A1 CA 2042642 A1 CA2042642 A1 CA 2042642A1 CA 002042642 A CA002042642 A CA 002042642A CA 2042642 A CA2042642 A CA 2042642A CA 2042642 A1 CA2042642 A1 CA 2042642A1
- Authority
- CA
- Canada
- Prior art keywords
- sheath
- femoral prosthesis
- stem
- prosthesis
- intramedullary femoral
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
- A61F2/02—Prostheses implantable into the body
- A61F2/30—Joints
- A61F2/32—Joints for the hip
- A61F2/36—Femoral heads ; Femoral endoprostheses
- A61F2/3662—Femoral shafts
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
- A61F2/02—Prostheses implantable into the body
- A61F2/30—Joints
- A61F2/30721—Accessories
- A61F2/30724—Spacers for centering an implant in a bone cavity, e.g. in a cement-receiving cavity
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
- A61F2/02—Prostheses implantable into the body
- A61F2/30—Joints
- A61F2/30767—Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
- A61F2/30907—Nets or sleeves applied to surface of prostheses or in cement
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
- A61F2/02—Prostheses implantable into the body
- A61F2/30—Joints
- A61F2/32—Joints for the hip
- A61F2/36—Femoral heads ; Femoral endoprostheses
- A61F2/3662—Femoral shafts
- A61F2/3676—Distal or diaphyseal parts of shafts
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
- A61F2/02—Prostheses implantable into the body
- A61F2/30—Joints
- A61F2002/30001—Additional features of subject-matter classified in A61F2/28, A61F2/30 and subgroups thereof
- A61F2002/30316—The prosthesis having different structural features at different locations within the same prosthesis; Connections between prosthetic parts; Special structural features of bone or joint prostheses not otherwise provided for
- A61F2002/30535—Special structural features of bone or joint prostheses not otherwise provided for
- A61F2002/30565—Special structural features of bone or joint prostheses not otherwise provided for having spring elements
- A61F2002/30571—Leaf springs
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
- A61F2/02—Prostheses implantable into the body
- A61F2/30—Joints
- A61F2002/30001—Additional features of subject-matter classified in A61F2/28, A61F2/30 and subgroups thereof
- A61F2002/30316—The prosthesis having different structural features at different locations within the same prosthesis; Connections between prosthetic parts; Special structural features of bone or joint prostheses not otherwise provided for
- A61F2002/30535—Special structural features of bone or joint prostheses not otherwise provided for
- A61F2002/30579—Special structural features of bone or joint prostheses not otherwise provided for with mechanically expandable devices, e.g. fixation devices
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
- A61F2/02—Prostheses implantable into the body
- A61F2/30—Joints
- A61F2/30767—Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
- A61F2/30771—Special external or bone-contacting surface, e.g. coating for improving bone ingrowth applied in original prostheses, e.g. holes or grooves
- A61F2002/30878—Special external or bone-contacting surface, e.g. coating for improving bone ingrowth applied in original prostheses, e.g. holes or grooves with non-sharp protrusions, for instance contacting the bone for anchoring, e.g. keels, pegs, pins, posts, shanks, stems, struts
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
- A61F2/02—Prostheses implantable into the body
- A61F2/30—Joints
- A61F2/30767—Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
- A61F2/30907—Nets or sleeves applied to surface of prostheses or in cement
- A61F2002/30919—Sleeves
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
- A61F2/02—Prostheses implantable into the body
- A61F2/30—Joints
- A61F2/46—Special tools or methods for implanting or extracting artificial joints, accessories, bone grafts or substitutes, or particular adaptations therefor
- A61F2002/4631—Special tools or methods for implanting or extracting artificial joints, accessories, bone grafts or substitutes, or particular adaptations therefor the prosthesis being specially adapted for being cemented
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2310/00—Prostheses classified in A61F2/28 or A61F2/30 - A61F2/44 being constructed from or coated with a particular material
- A61F2310/00005—The prosthesis being constructed from a particular material
- A61F2310/00353—Bone cement, e.g. polymethylmethacrylate or PMMA
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2310/00—Prostheses classified in A61F2/28 or A61F2/30 - A61F2/44 being constructed from or coated with a particular material
- A61F2310/00389—The prosthesis being coated or covered with a particular material
- A61F2310/00952—Coating, pre-coating or prosthesis-covering structure made of bone cement, e.g. pre-applied PMMA cement mantle
Abstract
ABSTRACT
A prosthetic intramedullary femoral prosthesis provided with a separate perforated sheath made from an acrylic material which is dimensioned to enclose the prosthesis stem from the distal tip to a location on the stem which will be adjacent the proximal cut end of the femur with which it will be used.
A prosthetic intramedullary femoral prosthesis provided with a separate perforated sheath made from an acrylic material which is dimensioned to enclose the prosthesis stem from the distal tip to a location on the stem which will be adjacent the proximal cut end of the femur with which it will be used.
Description
20426~2 PROSTHETIC INTRAMEDULLARY FEMORAL PROSTHESIS WITH PREFORMED
SHEATH
This invention relates to a prosthetic intramedullary femoral prosthesis provided with a separate preformed sheath and to a preformed sheath for use with such a prosthesis.
Many kinds of prosthetic intramedullary femoral prostheses are held in position in the medullary canal of the femur in which the prosthesis is planted by bone cement.
In the type of prosthesis in which there is no neck collar the prosthesis stem can sink further into the cement after fitting but this can cause difficulties in re-engagement of the tapering stem. There have been cases where the cement has been squeezed away totally during operative implantation such that there is direct contact between the metal stem and the bone forming a window in the cement mantle. Such a window is highly undesirable, it can be the source of cracks progressing through the cement mantle, and it can be a route by which debris of polyethylene, metal or bone cement can travel down the interface between the stem and the cement and out through the window and there it lodges in the bone and can be a source of bonelysis (bone death or loss of substance).
The present invention is intended to overcome some of the disadvantages referred to above.
According to the present invention a prosthetic intramedullary femoral prosthesis is provided with a separate preformed sheath made from an acrylic material which is dimensioned to enclose the prosthesis stem from the distal tip to a location on the stem which will be adjacent the proximal cut end of the femur with which it is used.
SHEATH
This invention relates to a prosthetic intramedullary femoral prosthesis provided with a separate preformed sheath and to a preformed sheath for use with such a prosthesis.
Many kinds of prosthetic intramedullary femoral prostheses are held in position in the medullary canal of the femur in which the prosthesis is planted by bone cement.
In the type of prosthesis in which there is no neck collar the prosthesis stem can sink further into the cement after fitting but this can cause difficulties in re-engagement of the tapering stem. There have been cases where the cement has been squeezed away totally during operative implantation such that there is direct contact between the metal stem and the bone forming a window in the cement mantle. Such a window is highly undesirable, it can be the source of cracks progressing through the cement mantle, and it can be a route by which debris of polyethylene, metal or bone cement can travel down the interface between the stem and the cement and out through the window and there it lodges in the bone and can be a source of bonelysis (bone death or loss of substance).
The present invention is intended to overcome some of the disadvantages referred to above.
According to the present invention a prosthetic intramedullary femoral prosthesis is provided with a separate preformed sheath made from an acrylic material which is dimensioned to enclose the prosthesis stem from the distal tip to a location on the stem which will be adjacent the proximal cut end of the femur with which it is used.
2~26~2 By preforming such a sheath there is reduced adhesion between the cement which holds the stem in place and the polished surface of the stem and thus preferably the sheet is dimensioned and constructed to allow the stem to move further into it under load.
The chances of a window or cracks being formed in the cement mantle is therefore reduced.
Preferably the distal end of the sheath is in the form of a cup, the inner end surface of which is spaced away from the distal end of the prosthesis stem to provide a void when initially located in position to accept subsequent inward movement after fitting. This ensures that the end of the sheath is not pierced by the stem by subsequent movement.
The sheath can be made from a material similar to bone cement material, fo~ example polymethylmethacrylate.
The sheath therefore forms what is, in effect, another layer of cement but it is not secured to the stem and it does ensure that the stem is completely covered.
The thickness of the sheath can be as small as possible provided it is strong enough not to crack during implantation and, for example, it can be between ~ mm and 5 mm and is preferably about 1 mm for practical use.
It will be appreciated that the sheath is moulded separately and is shaped to fit a particular size of prosthesis stem.
In a preferred embodiment the sheath is provided with means for centralising the prosthesis stem in the intramedullary canal and such centralising means may include outwardly projecting resiliently deformable abutments.
These abutments can be in the form of resilient wings, fins or arms which can deform inwardly and may be arranged to deform substantially radially inwardly or, deform circumferentially inwardly in the manner shown in the Applicants' co-pending British Patent Application No.
8924985.8 filed 6 November 1989 (Applicants' reference PCT
7713).
The invention also includes a preformed sheath for use with an intramedullary femoral prosthesis as set forth above.
The invention can be performed in various ways and two embodiments will now be described by way of example and with reference to the accompanying drawing in which :
Figure l is a side elevation of an intramedullary femoral prosthesis provided with a sheath according to the invention and, Figure 2 shows the dlstal end of a sheath according to a different embodiment.
As shown in Figure 1 an intramedullary femoral prosthesis 1 has a head 2 of known type which is connected through a neck 3 to an intramedullary stem 4~ The prosthesis is shown in position in a femur indicated by broken lines 5 the proximal cut end of which is indicated by reference numeral 6. In Figure 1 the prosthesis 1 is shown in position in the intramedullary canal 7 and is held by bone cement 8.
20426~
The stem 4 is enclosed in a sheath 9 which covers the stem from its distal tip lO to a location adjacent the proximal cut end 6 of the femur 5. In the arrangement shown this end 11 of the sheath is shown slightly protruding from the cement mantle 8.
The sheath is made from a material similar to bone cement material, for example polymethylmethacrylate, with a filler to make it more flexible, and its distal end 2 is somewhat longer than the end of the stem 10 to create a void 13.
The thickness of the sheath is about 1 mm and can be made as a separate moulding.
Moulded into the sheath are four thin outwardly projecting abutments 14 in the form of four equally spaced tangentially projecting wings or arms. These abutments act as a centraliser and to hold the stem 4 away from the wall of the medullary canal during implantation.
The projections can resiliently deform circumferentially inwardly as the stem, together with the sheath, is pushed into place in the canal 7.
With the sheath in position the centraliser provided by the abutments becomes well integrated with the cement, as does the remains of the sheath thus avoiding any weakening or hole creation.
If there is now a tendency for the stem to move further into the cement mantle this is accommodated by movement within the sheath which, it will be appreciated, has become integral with the cement mantlé itself but, because it is not connected to the stem adhesion between the 20426~2 cement and the stem is reduced and therefore the frictional resistance to the subsiding action or re-engagement of the stem is reduced.
An alternative construction of the sheath is shown in Figure 2 and in which similar reference numerals are used to indicated similar parts.
With this arrangement the void 13 is again created when the sheath 9 is placed on the stem 4 (not shown in Figure 2). In this construction however the abutments 14 are provided by three radially and upwardly extending arms 15 spaced around the sheath and which again act to centralise the stem in the medullary canal.
When the prosthesis is to be implanted the surgeon fits the appropriate size of preformed sheath to the stem of the prosthesis, the sheath including the integrally formed centraliser with a void creator on the distal tip. The assembled stem and sheath are then inserted into the bone cavity which has already been filled with normal bone cement in the normal way. The preformed cement sheath bonds directly with the bone cement inserted by the surgeon. The material of the sheath and the cement are identical or compatible so that they are bonded together.
It is important that the preformed sheath is separate from the stem, it cannot be provided merely by a coating applied to the stem as this will not give the same low friction characteristics at the surface of the stem which are required.
It is possible to provide a lubricant between the preformed sheath and the stem in order to reduce friction still further, a suitable sterile lubricant being used, for 20426~2 example sterile liquid paraffin.
The invention is intended to provide an optimisation of the interface conditions between the cement in an intramedullary canal and the surface of the stem. The avoidance of windows in the cement and direct contact between metal and bone is also an advantage.
The chances of a window or cracks being formed in the cement mantle is therefore reduced.
Preferably the distal end of the sheath is in the form of a cup, the inner end surface of which is spaced away from the distal end of the prosthesis stem to provide a void when initially located in position to accept subsequent inward movement after fitting. This ensures that the end of the sheath is not pierced by the stem by subsequent movement.
The sheath can be made from a material similar to bone cement material, fo~ example polymethylmethacrylate.
The sheath therefore forms what is, in effect, another layer of cement but it is not secured to the stem and it does ensure that the stem is completely covered.
The thickness of the sheath can be as small as possible provided it is strong enough not to crack during implantation and, for example, it can be between ~ mm and 5 mm and is preferably about 1 mm for practical use.
It will be appreciated that the sheath is moulded separately and is shaped to fit a particular size of prosthesis stem.
In a preferred embodiment the sheath is provided with means for centralising the prosthesis stem in the intramedullary canal and such centralising means may include outwardly projecting resiliently deformable abutments.
These abutments can be in the form of resilient wings, fins or arms which can deform inwardly and may be arranged to deform substantially radially inwardly or, deform circumferentially inwardly in the manner shown in the Applicants' co-pending British Patent Application No.
8924985.8 filed 6 November 1989 (Applicants' reference PCT
7713).
The invention also includes a preformed sheath for use with an intramedullary femoral prosthesis as set forth above.
The invention can be performed in various ways and two embodiments will now be described by way of example and with reference to the accompanying drawing in which :
Figure l is a side elevation of an intramedullary femoral prosthesis provided with a sheath according to the invention and, Figure 2 shows the dlstal end of a sheath according to a different embodiment.
As shown in Figure 1 an intramedullary femoral prosthesis 1 has a head 2 of known type which is connected through a neck 3 to an intramedullary stem 4~ The prosthesis is shown in position in a femur indicated by broken lines 5 the proximal cut end of which is indicated by reference numeral 6. In Figure 1 the prosthesis 1 is shown in position in the intramedullary canal 7 and is held by bone cement 8.
20426~
The stem 4 is enclosed in a sheath 9 which covers the stem from its distal tip lO to a location adjacent the proximal cut end 6 of the femur 5. In the arrangement shown this end 11 of the sheath is shown slightly protruding from the cement mantle 8.
The sheath is made from a material similar to bone cement material, for example polymethylmethacrylate, with a filler to make it more flexible, and its distal end 2 is somewhat longer than the end of the stem 10 to create a void 13.
The thickness of the sheath is about 1 mm and can be made as a separate moulding.
Moulded into the sheath are four thin outwardly projecting abutments 14 in the form of four equally spaced tangentially projecting wings or arms. These abutments act as a centraliser and to hold the stem 4 away from the wall of the medullary canal during implantation.
The projections can resiliently deform circumferentially inwardly as the stem, together with the sheath, is pushed into place in the canal 7.
With the sheath in position the centraliser provided by the abutments becomes well integrated with the cement, as does the remains of the sheath thus avoiding any weakening or hole creation.
If there is now a tendency for the stem to move further into the cement mantle this is accommodated by movement within the sheath which, it will be appreciated, has become integral with the cement mantlé itself but, because it is not connected to the stem adhesion between the 20426~2 cement and the stem is reduced and therefore the frictional resistance to the subsiding action or re-engagement of the stem is reduced.
An alternative construction of the sheath is shown in Figure 2 and in which similar reference numerals are used to indicated similar parts.
With this arrangement the void 13 is again created when the sheath 9 is placed on the stem 4 (not shown in Figure 2). In this construction however the abutments 14 are provided by three radially and upwardly extending arms 15 spaced around the sheath and which again act to centralise the stem in the medullary canal.
When the prosthesis is to be implanted the surgeon fits the appropriate size of preformed sheath to the stem of the prosthesis, the sheath including the integrally formed centraliser with a void creator on the distal tip. The assembled stem and sheath are then inserted into the bone cavity which has already been filled with normal bone cement in the normal way. The preformed cement sheath bonds directly with the bone cement inserted by the surgeon. The material of the sheath and the cement are identical or compatible so that they are bonded together.
It is important that the preformed sheath is separate from the stem, it cannot be provided merely by a coating applied to the stem as this will not give the same low friction characteristics at the surface of the stem which are required.
It is possible to provide a lubricant between the preformed sheath and the stem in order to reduce friction still further, a suitable sterile lubricant being used, for 20426~2 example sterile liquid paraffin.
The invention is intended to provide an optimisation of the interface conditions between the cement in an intramedullary canal and the surface of the stem. The avoidance of windows in the cement and direct contact between metal and bone is also an advantage.
Claims (12)
1. A prosthetic intramedullary femoral prosthesis provided with a separate perforated sheath made from an acrylic material which is dimensioned to enclose the prosthesis stem from the distal tip to a location on the stem which will be adjacent the proximal cut end of the femur with which it will be used.
2. A prosthetic intramedullary femoral prosthesis as claimed in claim 1 in which the sheath is dimensioned and constructed to allow the stem to move further into it under load.
3. A prosthetic intramedullary femoral prosthesis as claimed in claim 3 in which the distal end of the sheath is in the form of a cup the inner end surface of which is spaced away from the distal end of the prosthesis stem to provide a void when initially located in position, to accept subsequent inward movement after fitting.
4. A prosthetic intramedullary femoral prosthesis as claimed in claims 1 to 3 in which the sheath is made from a material similar to bone cement, eg. polymethylmethacrylate.
5. A prosthetic intramedullary femoral prosthesis as claimed in claims 1 to 4 in which the sheath has a thickness of between 1/2 mm and 2 mm.
6. A prosthetic intramedullary femoral prosthesis as claimed in claim 5 in which the sheath has a thickness of substantially 1 mm.
7. A prosthetic intramedullary femoral prosthesis as claimed in claims 1 to 6 in which said sheath is provided with means for centralising the prosthesis stem in the intramedullary canal of the femur with which it is to be used.
8. A prosthetic intramedullary femoral prosthesis as claimed in claim 7 in which the centralising means include outwardly projecting resiliently deformable abutments.
9. A prosthetic intramedullary femoral prosthesis as claimed in claim 8 in which the resilient abutments are in the form of resilient wings, fins or arms which can deform inwardly.
10. A prosthetic intramedullary femoral prosthesis as claimed in claim 9 in which the abutments can deform substantially radially inwardly.
11. A prosthetic intramedullary femoral prosthesis as claimed in claim 9 in which the abutments can deform circumferentially inwardly.
12. A perforated sheath for use with an intramedullary femoral prosthesis as claimed in any one of the preceding claims.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9011132.6 | 1990-05-17 | ||
GB909011132A GB9011132D0 (en) | 1990-05-17 | 1990-05-17 | Phosthetic intramedullary femoral prosthesis with preformed sheath |
Publications (1)
Publication Number | Publication Date |
---|---|
CA2042642A1 true CA2042642A1 (en) | 1991-11-18 |
Family
ID=10676187
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA002042642A Abandoned CA2042642A1 (en) | 1990-05-17 | 1991-05-15 | Prosthetic intramedullary femoral prosthesis with preformed sheath |
Country Status (12)
Country | Link |
---|---|
US (1) | US5197990A (en) |
EP (1) | EP0457464B1 (en) |
JP (1) | JPH0739558A (en) |
AT (1) | ATE104129T1 (en) |
AU (1) | AU642247B2 (en) |
CA (1) | CA2042642A1 (en) |
DE (2) | DE69101666T2 (en) |
DK (1) | DK0457464T3 (en) |
ES (1) | ES2051082T3 (en) |
GB (1) | GB9011132D0 (en) |
IE (1) | IE64392B1 (en) |
PT (1) | PT97691B (en) |
Families Citing this family (36)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5116380A (en) * | 1991-02-28 | 1992-05-26 | Zimmer, Inc. | Prosthetic implant with spacers having tapered trailing edges |
GR1002517B (en) * | 1991-09-30 | 1997-01-23 | Johnson & Johnson Orthopaedics Inc. | Hip prosthesis. |
GB9201734D0 (en) * | 1992-01-28 | 1992-03-11 | Howmedica | Femoral component for use in a replacement hip prosthesis |
GB9202248D0 (en) * | 1992-02-03 | 1992-03-18 | Howmedica | Prosthesis for attachement without bone cement and method of attaching |
US5571193A (en) * | 1992-03-12 | 1996-11-05 | Kampner; Stanley L. | Implant with reinforced resorbable stem |
EP0563502B1 (en) * | 1992-04-03 | 1995-11-29 | SULZER Medizinaltechnik AG | Metal stem |
US5314493A (en) * | 1992-09-10 | 1994-05-24 | Mikhail Michael W E | Femoral hip joint prosthesis |
IL104313A0 (en) * | 1993-01-06 | 1993-05-13 | Bromberg A & Co Ltd | Device for fixing a prosthesis to a bone |
WO1994020046A1 (en) * | 1993-03-12 | 1994-09-15 | Brigham And Women's Hospital | Bone prosthesis and method of implanting the same |
US5443523A (en) * | 1994-03-18 | 1995-08-22 | Mikhail; W. E. Michael | Femoral stem cement mantle |
US5507814A (en) * | 1994-03-30 | 1996-04-16 | Northwestern University | Orthopedic implant with self-reinforced mantle |
US5697932A (en) * | 1994-11-09 | 1997-12-16 | Osteonics Corp. | Bone graft delivery system and method |
DE19605735C2 (en) * | 1995-12-01 | 2002-01-10 | Dietmar A Kumm | Periprosthetic retention systems |
DE19613200C2 (en) * | 1996-04-02 | 2001-12-20 | Dietmar A Kumm | Periprosthetic mounting systems for femoral head endoprostheses |
US5871549A (en) * | 1996-12-12 | 1999-02-16 | Johnson & Johnson Professional, Inc. | Femoral stem with reduced coefficient of friction with respect to bone cement |
US5997581A (en) * | 1997-12-29 | 1999-12-07 | Johnson & Johnson Professional, Inc. | Hip stem cement spacer |
US6214053B1 (en) | 1998-06-04 | 2001-04-10 | Benoist Girard Sas | Prosthesis with centralizer and centralizer for use therewith |
GB9812069D0 (en) | 1998-06-04 | 1998-08-05 | Benoist Girard & Cie | Prosthesis provided with a mantle |
US6383226B1 (en) | 1998-06-09 | 2002-05-07 | The Board Of Trustees Of The Leland Stanford Junior University | Prostheses having curvilinear collars |
GB9821993D0 (en) * | 1998-10-08 | 1998-12-02 | Johnson & Johnson Medical Ltd | Centraliser |
GB0027893D0 (en) | 2000-11-15 | 2000-12-27 | Benoist Girard & Cie | Prosthetic implant cement deflector and a set of components to carry out a prosthetic implant employing such a deflector |
ITPI20020002A1 (en) * | 2002-01-04 | 2003-07-04 | Pierluigi Versari | STABILIZED STEM FOR PROSTHESIS |
US7534271B2 (en) * | 2004-01-22 | 2009-05-19 | Smith + Nephew | Femoral hip prosthesis and method of implantation |
US20060241759A1 (en) * | 2005-04-25 | 2006-10-26 | Sdgi Holdings, Inc. | Oriented polymeric spinal implants |
US8961516B2 (en) | 2005-05-18 | 2015-02-24 | Sonoma Orthopedic Products, Inc. | Straight intramedullary fracture fixation devices and methods |
WO2006124764A1 (en) * | 2005-05-18 | 2006-11-23 | Sonoma Orthopedic Products, Inc. | Minimally invasive actuable bone fixation devices, systems and methods of use |
US9060820B2 (en) | 2005-05-18 | 2015-06-23 | Sonoma Orthopedic Products, Inc. | Segmented intramedullary fracture fixation devices and methods |
NL1032851C2 (en) * | 2006-11-10 | 2008-05-14 | Fondel Finance B V | Kit and method for fixing a prosthesis or part thereof and / or filling bony defects. |
CA2670263A1 (en) | 2006-11-22 | 2008-05-29 | Sonoma Orthopedic Products, Inc. | Fracture fixation device, tools and methods |
US20080149115A1 (en) * | 2006-11-22 | 2008-06-26 | Sonoma Orthopedic Products, Inc. | Surgical station for orthopedic reconstruction surgery |
AU2007323570A1 (en) * | 2006-11-22 | 2008-05-29 | Sonoma Orthopedic Products Inc. | Surgical tools for use in deploying bone repair devices |
US20080132896A1 (en) * | 2006-11-22 | 2008-06-05 | Sonoma Orthopedic Products, Inc. | Curved orthopedic tool |
WO2009152273A1 (en) * | 2008-06-10 | 2009-12-17 | Sonoma Orthopedic Products, Inc. | Fracture fixation device, tools and methods |
CA2738478A1 (en) | 2008-09-26 | 2010-04-01 | Sonoma Orthopedic Products, Inc. | Bone fixation device, tools and methods |
US9770278B2 (en) | 2014-01-17 | 2017-09-26 | Arthrex, Inc. | Dual tip guide wire |
US9814499B2 (en) | 2014-09-30 | 2017-11-14 | Arthrex, Inc. | Intramedullary fracture fixation devices and methods |
Family Cites Families (21)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1409053A (en) * | 1971-09-24 | 1975-10-08 | Nat Res Dev | Orthopaedic prosthetic devices |
CH557169A (en) * | 1972-10-26 | 1974-12-31 | Sulzer Ag | BONE IMPLANT. |
US4064567A (en) * | 1976-09-15 | 1977-12-27 | The Sampson Corporation | Prosthesis-to-bone interface system |
DE2808740A1 (en) * | 1978-03-01 | 1979-09-06 | Omar Pacha Nabil Dr | Artificial bone joint for permanent insertion in body - uses parts inside bones enclosed in compatible implantation material |
GB2052267B (en) * | 1979-06-30 | 1983-06-22 | Hardinge K | Medullary canal plug |
US4283799A (en) * | 1979-09-10 | 1981-08-18 | Massachusetts Institute Of Technology | Pre-coated body implant |
GB2104391B (en) * | 1981-08-25 | 1984-12-19 | Univ Exeter | Spacer for intra-medullary implant |
US4919665A (en) * | 1982-04-19 | 1990-04-24 | Homsy Charles A | Implantation of articulating joint prosthesis |
DE3334058C2 (en) * | 1983-09-21 | 1985-07-25 | Ulrich Dr.-Ing. 5600 Wuppertal Witzel | Thigh section for a hip joint prosthesis |
GB8401059D0 (en) * | 1984-01-16 | 1984-02-15 | Exeter University Of | Fixation of implants in bone |
GB8409714D0 (en) * | 1984-04-13 | 1984-05-23 | Finsbury Instr Ltd | Hip implant |
GB2162753A (en) * | 1984-06-22 | 1986-02-12 | Thackray C F Ltd | Sleeve for metal implant into bone |
GB8426866D0 (en) * | 1984-10-24 | 1984-11-28 | Finsbury Instr Ltd | Bone implants |
CH664081A5 (en) * | 1984-12-13 | 1988-02-15 | Sulzer Ag | HIP PROSTHESIS. |
US4735625A (en) * | 1985-09-11 | 1988-04-05 | Richards Medical Company | Bone cement reinforcement and method |
US4728335A (en) * | 1986-12-15 | 1988-03-01 | Jurgutis John A | Hip prosthesis |
FR2610515A1 (en) * | 1987-02-09 | 1988-08-12 | Jean Lannelongue | SHOULDER PROSTHESIS |
US4888023B1 (en) * | 1988-01-19 | 1996-01-23 | Osteonics Corp | Femoral prosthesis with uncoupled distal tip |
DE3802214A1 (en) * | 1988-01-26 | 1989-07-27 | Roland Man Druckmasch | Adapter piece for anchorage of a prosthesis part in a bone |
GB8924985D0 (en) * | 1989-11-06 | 1989-12-28 | Howmedica | Centaliser for the stem of an intramedullary prosthesis |
US5080680A (en) * | 1990-09-04 | 1992-01-14 | Mikhail Michael W E | Femoral stem prosthesis with preapplied cement mantle |
-
1990
- 1990-05-17 GB GB909011132A patent/GB9011132D0/en active Pending
-
1991
- 1991-05-01 EP EP91303958A patent/EP0457464B1/en not_active Expired - Lifetime
- 1991-05-01 DE DE69101666T patent/DE69101666T2/en not_active Expired - Fee Related
- 1991-05-01 DK DK91303958.2T patent/DK0457464T3/en active
- 1991-05-01 AT AT91303958T patent/ATE104129T1/en not_active IP Right Cessation
- 1991-05-01 ES ES91303958T patent/ES2051082T3/en not_active Expired - Lifetime
- 1991-05-02 IE IE149191A patent/IE64392B1/en not_active IP Right Cessation
- 1991-05-10 AU AU76454/91A patent/AU642247B2/en not_active Ceased
- 1991-05-11 DE DE9105872U patent/DE9105872U1/de not_active Expired - Lifetime
- 1991-05-15 CA CA002042642A patent/CA2042642A1/en not_active Abandoned
- 1991-05-16 PT PT97691A patent/PT97691B/en not_active IP Right Cessation
- 1991-05-16 JP JP3111870A patent/JPH0739558A/en active Pending
- 1991-05-16 US US07/701,556 patent/US5197990A/en not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
---|---|
ATE104129T1 (en) | 1994-04-15 |
IE64392B1 (en) | 1995-08-09 |
DE69101666D1 (en) | 1994-05-19 |
EP0457464B1 (en) | 1994-04-13 |
PT97691A (en) | 1993-07-30 |
ES2051082T3 (en) | 1994-06-01 |
DK0457464T3 (en) | 1994-06-27 |
EP0457464A1 (en) | 1991-11-21 |
DE69101666T2 (en) | 1994-07-28 |
DE9105872U1 (en) | 1991-07-18 |
US5197990A (en) | 1993-03-30 |
JPH0739558A (en) | 1995-02-10 |
AU7645491A (en) | 1991-11-21 |
IE911491A1 (en) | 1991-11-20 |
PT97691B (en) | 1998-12-31 |
AU642247B2 (en) | 1993-10-14 |
GB9011132D0 (en) | 1990-07-04 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP0457464B1 (en) | Prosthetic intramedullary femoral prosthesis with preformed sheath | |
AU654226B2 (en) | Femoral component for use in a replacement hip prosthesis | |
US6214053B1 (en) | Prosthesis with centralizer and centralizer for use therewith | |
EP0501116B1 (en) | Prosthetic implant with spacers having tapered trailing edges | |
US5092892A (en) | Intramedullary centralizer | |
US4302855A (en) | Plug for the intramedallary canal of a bone and method | |
US5755793A (en) | Centralizer for a prosthetic implant | |
GB2104391A (en) | Spacer for intra-medullary implant | |
EP1195148A2 (en) | Intramedullary centralizer having fins of varying length and associated method of implanting an orthopaedic component into a patient | |
EP0993811B1 (en) | Centraliser | |
US20010004712A1 (en) | Prosthesis provided with a mantle | |
EP0962198B1 (en) | Plugging and centralising device for locating the stem of a prosthesis | |
AU781903B2 (en) | Prosthetic implant cement deflector and a set of components to carry out a prosthetic implant employing such deflector | |
EP0962197A2 (en) | Prosthesis with centraliser and centraliser for use therewith | |
EP0995410A2 (en) | A prosthetic implant cement deflector |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
FZDE | Discontinued |