CA2059310A1 - Proximal centralizer with removable handle - Google Patents
Proximal centralizer with removable handleInfo
- Publication number
- CA2059310A1 CA2059310A1 CA002059310A CA2059310A CA2059310A1 CA 2059310 A1 CA2059310 A1 CA 2059310A1 CA 002059310 A CA002059310 A CA 002059310A CA 2059310 A CA2059310 A CA 2059310A CA 2059310 A1 CA2059310 A1 CA 2059310A1
- Authority
- CA
- Canada
- Prior art keywords
- centralizer
- implant
- proximal
- handle
- spacing
- 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
Abstract
PROXIMAL CENTRALIZER WITH REMOVABLE HANDLE
Abstract of the Disclosure A proximal centralizer for positioning the proximal end of a femoral implant a predetermined distance from the medial wall of the intramedullary canal. The spacer is preferably formed from poly methyl methacrylate and includes a handle portion and a centralizer portion interconnected by a temporary living hinge. In use the centralizer portion of the centralizer is carried by the implant adjacent the collar in contact with the proximal medial wall and adjacent side walls of the implant. During insertion of the implant into the cement filled intramedullary canal the handle provides access to the surgeon to hold the centralizer portion tightly against the implant. After the implant with the centralizer attached is inserted into the intramedullary canal, the surgeon flexes the temporary living hinge to break off the handle portion of the centralizer. The handle portion is then discarded.
Abstract of the Disclosure A proximal centralizer for positioning the proximal end of a femoral implant a predetermined distance from the medial wall of the intramedullary canal. The spacer is preferably formed from poly methyl methacrylate and includes a handle portion and a centralizer portion interconnected by a temporary living hinge. In use the centralizer portion of the centralizer is carried by the implant adjacent the collar in contact with the proximal medial wall and adjacent side walls of the implant. During insertion of the implant into the cement filled intramedullary canal the handle provides access to the surgeon to hold the centralizer portion tightly against the implant. After the implant with the centralizer attached is inserted into the intramedullary canal, the surgeon flexes the temporary living hinge to break off the handle portion of the centralizer. The handle portion is then discarded.
Description
2 0 ~
Patent ~0163 PROXIMAL CENTRALIZER WITH REMOVABLE HANDLE
Field of the Invention This invention relates to a proximal centralizer for a femoral implant and has specific relevance to a proximal centralizer having a removable handle.
Summary of the Invention This invention relates to a proximal centralizer for positioning the proximal end of a femoral implant a predetermined distance from the medial wall of the intramedullary canal. The spacer is preferably formed from poly methyl methacrylate and includes as integral components a handle portion and a centralizer portion spaced apart from one another by breakable connectors. In use the centralizer portion of the centralizer is carried by the implant adjacent the collar in contact with the medial wall and adjacent side walls of the implant. During insertion of the implant into the cement filled intramedullary canal the handle provides access to the surgeon to hold the centralizer portion tightly against the implant. After the implant with the centralizer attached is inserted into the intramedullary canal, the surgeon pivots the handle portion abou-t the centralizer portion to break the breakable connectors adjacent the centralizer portion for removal of the handle portion. The handle portion is then discarded.
In the preferred embodiment, the handle portion may be substantially symmetrical with the centralizer portion in shape, but formed having a different cross-sectional thickness. In essence, the proximal centralizer of the preferred embodiment consists of two centralizer portions of distinct cross sectional thicknesses interconnected by a breakable connectors. During the implant procedure, the surgeon may position either centralizer portion adjacent the medial wall of the implant with the other 2~93~ -surgeon. Since the two centralizer portions on the cen~ralizer have distinct cross~sectional dimensions, the choice of which centralizer portion to use is dictated by the desired spaciny between the medial wall of the canal and the proximal medial wall of the implant as determined by the surgeon.
Accordingly, it is an object of the invention to provide a novel proximal centralizer for a femoral implant.
Another object of the invention is to provide a proximal centralizer for a femoral implant having a centralizer portion and a handle portion.
Yet another object of the invention is to provide a proximal centralizer for a femoral implant having a pair of centralizer portions connected by breakable connectors.
Still other objects of the invention will become apparent UpOIl a reading of the following description taken with the accompanying drawings.
Brief Description of the Fiqures Figure 1 is a perspective view of the invention.
Figure 2 is a top down elevational view taken from Fig. 1 Figure 3 is a fragmented side elevational view of the invention shown in use in its intended environment connected to a hip stem implant which is partially inserted within a prepared cement filled intramedullary canal. The implant and canal are shown in broken lines.
Figure 4 is the fragmented side elevational view of Fig 3 with the implant fully inserted and the unused portion of the centralizer removed.
Figure 5 is a perspective view of an alternative embodiment.
Figure 6 is a top down elevational view of Fig. 5.
.
:-` 2 ~
Description of the P~referred ~ odiments The preferred embodiments herein described are not intended to be exhaustive or to limit the invention to the precise forms dlsclosed. Rather, they are chosen and described in order to best explain the invention so that others skilled in the art may utilize the teachings.
For the purposes of illustration a prosthetic hip implant 1 and proximal end of a prepared femur 6 is illustrated in Figs. 3 and 4 in broken lines only. Implant l includes a stem 4 and a neck 3 integrally formed and defining a collar 5 at their junction.
Stem 4 includes a medial wall 2. The femur 6 includes a prepared intramedullary canal 7 having a proximal end and a greater trochanter 8. A quantity of poly methyl methacrylate 9 is placed in canaI 7 in keeping with standard hip replacement techniques.
lS Proximal centralizer l~ as shown in Fi~s. 1-4 is illustrated as being an integral unit and includes a centralizer portion 12 and a centralizer portion ll. Centralizer portion 12 includes a generally U-shaped spacer 14 with integral breakable connectors 15 extending longitudinally as shown. Spacer 14 is inclined slightly relative to the vertical and has a cross-section of a predetermined thickness. Similarly, centralizer portion ll includes a generally U-shaped spacer 13 with integral breakable connectors 19 extending longitudinally as shown. Spacer 14 is also incline~ slightly relative to the vertical and is formed having a cross-section of a predetermined thickness. In the preferred embodiment, the spacers 13 and 14 are inclined relative to the vertical (as mentioned) to match the slope of the implant's proximal medial wall. Also in t~e preferred embodiment the cross-sectional thickness of spacer 14 is greater than the cross-section thickness of spacer 13. As mentioned, centralizer portion 12 and centralizer portion ll are interconnected by breakable connectors l~ and 19 at junction 16.
2~9~0 centralizer 10 is preferably relatively brittle when solid.
Therefore, connectors 15 and 19 are referred to as breakable since bending the connectors causes them ko break adjacen~ their respective spacer. The use of PMMA for spacers is well known and possesses many advantages in use with PMMA cement.
In use, a surgeon determines the amount of spacing desired between the medial wall of a prepared intramedullary canal and the - proximal medial wall of a femoral implant 1. The centralizer 10 is slid onto the distal end of the implant and along the stem toward the proximal end. Either centralizer portion 12 or centralizer portion 11 may be positioned to engage the underside of collar 5 of the implant to orient the particular centralizer portion desired adjacent the medial wall of the implant~ Which centralizer portion (11,12) is positioned adjacent the medial wall is one of surgeon choice dependent upon the desired spacing between the medial wall of the implant and the adjacent bone structure. For example, assume the thickness of spacer 13 is 2mm and the thickness of spacer 14 is lmm. If a surgeon determines a 2mm spacing between the proximal medial wall of the implant and the bone structure is appropriate, centralizer 10 would be positioned as illustrated in Fig. 3 with centralizer portion 11 in contact with the implant and portion 12 extending rearwardly therefrom and slightly above the greater trochanter. Centralizer portion 12 in assence becomes a handle for centralizer 10 to allow the surgaon to hold the centralizer portion 11 secure during insertion of the implant 1.
When the implant is fully inserted, centralizer portion 11 is between the ~emoral bone and the proximal medial wall of the implant thereby insuring a 2mm spacing between bone and implant.
If the surgeon requires only a lmm spacing between bone and implant then centralizer portion 12 is positioned adjacent the implant prior to insertion and portion 11 extends rearwardly to act as a handle. It should be understood that the exact thickness of spacers 13 and 14 is one of mere desi~n choice and should not ~e 2~3~
inserted into the intramedullary canal and the cement is allowed to at leas-t partially cure and polymerize wi~h the centralizer, th~
surgeon pivots the rearwardly extendiny centralizer portion (12 in Fig.~) upwardly toward implant neck 3. Pivoting the centralizer in this manner causes legs 19 in Fig. 4 to break from spacer 13 preferably adjacent the spacer. The unused centralizer portion is then discarded. It should be noted that centralizer portions 11 and 12 are angled slightly relative to one another to provide clearance for the greater trochanter when the implant and centralizer are insertion.
An alternative embodiment of the invention is illustrated in Figs. 5 and 6. The proximal centralizer 20 of Figs. 5 and 6 includes a centralizer portion 21 and a handle portion 22 interconnected by temporary living hinge 26 formed by recesses 27.
As with centralizer 10 of the first embodiment, centralizer 20 is preferably formed from PMMA. Handle portion 21 includes a spacer 23 having a predetermined cross sectional thickness and being inclined slightly relative to vertical. Handle portion 22 includes slightly arcuate finger tabs 24,25 extending transversely relative to the plane of spacer 23. In use, centralizer 20 is slid upwardly on the stem of an implant (not shown) until butting against the collar of the implant. The implant is inserted into the intramedullary canal while the surgeon maintains centralizer 20 in position by grasping thè finger tabs 24, 25 and applying tension.
When the implant is fully seated and the cement is allowed to at least partially cure, the surgeon pivots handle portion 22 about hinge 26 to break off the handle from centralizer portion 210 Handle portion 22 may then be discarded.
It should be understood that the invention is not to be limited to the precise forms disclosed but may be modified within the keeping of the appended claims.
Patent ~0163 PROXIMAL CENTRALIZER WITH REMOVABLE HANDLE
Field of the Invention This invention relates to a proximal centralizer for a femoral implant and has specific relevance to a proximal centralizer having a removable handle.
Summary of the Invention This invention relates to a proximal centralizer for positioning the proximal end of a femoral implant a predetermined distance from the medial wall of the intramedullary canal. The spacer is preferably formed from poly methyl methacrylate and includes as integral components a handle portion and a centralizer portion spaced apart from one another by breakable connectors. In use the centralizer portion of the centralizer is carried by the implant adjacent the collar in contact with the medial wall and adjacent side walls of the implant. During insertion of the implant into the cement filled intramedullary canal the handle provides access to the surgeon to hold the centralizer portion tightly against the implant. After the implant with the centralizer attached is inserted into the intramedullary canal, the surgeon pivots the handle portion abou-t the centralizer portion to break the breakable connectors adjacent the centralizer portion for removal of the handle portion. The handle portion is then discarded.
In the preferred embodiment, the handle portion may be substantially symmetrical with the centralizer portion in shape, but formed having a different cross-sectional thickness. In essence, the proximal centralizer of the preferred embodiment consists of two centralizer portions of distinct cross sectional thicknesses interconnected by a breakable connectors. During the implant procedure, the surgeon may position either centralizer portion adjacent the medial wall of the implant with the other 2~93~ -surgeon. Since the two centralizer portions on the cen~ralizer have distinct cross~sectional dimensions, the choice of which centralizer portion to use is dictated by the desired spaciny between the medial wall of the canal and the proximal medial wall of the implant as determined by the surgeon.
Accordingly, it is an object of the invention to provide a novel proximal centralizer for a femoral implant.
Another object of the invention is to provide a proximal centralizer for a femoral implant having a centralizer portion and a handle portion.
Yet another object of the invention is to provide a proximal centralizer for a femoral implant having a pair of centralizer portions connected by breakable connectors.
Still other objects of the invention will become apparent UpOIl a reading of the following description taken with the accompanying drawings.
Brief Description of the Fiqures Figure 1 is a perspective view of the invention.
Figure 2 is a top down elevational view taken from Fig. 1 Figure 3 is a fragmented side elevational view of the invention shown in use in its intended environment connected to a hip stem implant which is partially inserted within a prepared cement filled intramedullary canal. The implant and canal are shown in broken lines.
Figure 4 is the fragmented side elevational view of Fig 3 with the implant fully inserted and the unused portion of the centralizer removed.
Figure 5 is a perspective view of an alternative embodiment.
Figure 6 is a top down elevational view of Fig. 5.
.
:-` 2 ~
Description of the P~referred ~ odiments The preferred embodiments herein described are not intended to be exhaustive or to limit the invention to the precise forms dlsclosed. Rather, they are chosen and described in order to best explain the invention so that others skilled in the art may utilize the teachings.
For the purposes of illustration a prosthetic hip implant 1 and proximal end of a prepared femur 6 is illustrated in Figs. 3 and 4 in broken lines only. Implant l includes a stem 4 and a neck 3 integrally formed and defining a collar 5 at their junction.
Stem 4 includes a medial wall 2. The femur 6 includes a prepared intramedullary canal 7 having a proximal end and a greater trochanter 8. A quantity of poly methyl methacrylate 9 is placed in canaI 7 in keeping with standard hip replacement techniques.
lS Proximal centralizer l~ as shown in Fi~s. 1-4 is illustrated as being an integral unit and includes a centralizer portion 12 and a centralizer portion ll. Centralizer portion 12 includes a generally U-shaped spacer 14 with integral breakable connectors 15 extending longitudinally as shown. Spacer 14 is inclined slightly relative to the vertical and has a cross-section of a predetermined thickness. Similarly, centralizer portion ll includes a generally U-shaped spacer 13 with integral breakable connectors 19 extending longitudinally as shown. Spacer 14 is also incline~ slightly relative to the vertical and is formed having a cross-section of a predetermined thickness. In the preferred embodiment, the spacers 13 and 14 are inclined relative to the vertical (as mentioned) to match the slope of the implant's proximal medial wall. Also in t~e preferred embodiment the cross-sectional thickness of spacer 14 is greater than the cross-section thickness of spacer 13. As mentioned, centralizer portion 12 and centralizer portion ll are interconnected by breakable connectors l~ and 19 at junction 16.
2~9~0 centralizer 10 is preferably relatively brittle when solid.
Therefore, connectors 15 and 19 are referred to as breakable since bending the connectors causes them ko break adjacen~ their respective spacer. The use of PMMA for spacers is well known and possesses many advantages in use with PMMA cement.
In use, a surgeon determines the amount of spacing desired between the medial wall of a prepared intramedullary canal and the - proximal medial wall of a femoral implant 1. The centralizer 10 is slid onto the distal end of the implant and along the stem toward the proximal end. Either centralizer portion 12 or centralizer portion 11 may be positioned to engage the underside of collar 5 of the implant to orient the particular centralizer portion desired adjacent the medial wall of the implant~ Which centralizer portion (11,12) is positioned adjacent the medial wall is one of surgeon choice dependent upon the desired spacing between the medial wall of the implant and the adjacent bone structure. For example, assume the thickness of spacer 13 is 2mm and the thickness of spacer 14 is lmm. If a surgeon determines a 2mm spacing between the proximal medial wall of the implant and the bone structure is appropriate, centralizer 10 would be positioned as illustrated in Fig. 3 with centralizer portion 11 in contact with the implant and portion 12 extending rearwardly therefrom and slightly above the greater trochanter. Centralizer portion 12 in assence becomes a handle for centralizer 10 to allow the surgaon to hold the centralizer portion 11 secure during insertion of the implant 1.
When the implant is fully inserted, centralizer portion 11 is between the ~emoral bone and the proximal medial wall of the implant thereby insuring a 2mm spacing between bone and implant.
If the surgeon requires only a lmm spacing between bone and implant then centralizer portion 12 is positioned adjacent the implant prior to insertion and portion 11 extends rearwardly to act as a handle. It should be understood that the exact thickness of spacers 13 and 14 is one of mere desi~n choice and should not ~e 2~3~
inserted into the intramedullary canal and the cement is allowed to at leas-t partially cure and polymerize wi~h the centralizer, th~
surgeon pivots the rearwardly extendiny centralizer portion (12 in Fig.~) upwardly toward implant neck 3. Pivoting the centralizer in this manner causes legs 19 in Fig. 4 to break from spacer 13 preferably adjacent the spacer. The unused centralizer portion is then discarded. It should be noted that centralizer portions 11 and 12 are angled slightly relative to one another to provide clearance for the greater trochanter when the implant and centralizer are insertion.
An alternative embodiment of the invention is illustrated in Figs. 5 and 6. The proximal centralizer 20 of Figs. 5 and 6 includes a centralizer portion 21 and a handle portion 22 interconnected by temporary living hinge 26 formed by recesses 27.
As with centralizer 10 of the first embodiment, centralizer 20 is preferably formed from PMMA. Handle portion 21 includes a spacer 23 having a predetermined cross sectional thickness and being inclined slightly relative to vertical. Handle portion 22 includes slightly arcuate finger tabs 24,25 extending transversely relative to the plane of spacer 23. In use, centralizer 20 is slid upwardly on the stem of an implant (not shown) until butting against the collar of the implant. The implant is inserted into the intramedullary canal while the surgeon maintains centralizer 20 in position by grasping thè finger tabs 24, 25 and applying tension.
When the implant is fully seated and the cement is allowed to at least partially cure, the surgeon pivots handle portion 22 about hinge 26 to break off the handle from centralizer portion 210 Handle portion 22 may then be discarded.
It should be understood that the invention is not to be limited to the precise forms disclosed but may be modified within the keeping of the appended claims.
Claims (7)
1. A proximal centralizer for a prosthetic hip implant comprising a centralizer means adapted for engagement with a proximal end of a stem of said implant for spacing said stem proximal end a predetermined distance from a supporting bone structure, means for providing a handle, and means for connecting said centralizer means to said handle means, said connecting means being breakable for disconnecting said handle means from said.
centralizer means.
centralizer means.
2. The proximal centralizer of Claim 1 wherein said centralizer means includes a generally U-shaped spacer having a predetermined cross-sectional thickness.
3. The proximal centralizer of Claim 1 wherein said handle means includes a pair of transverse projections extending therefrom.
4. The proximal centralizer of Claim 2 wherein said handle means includes a generally U-shaped spacer substantially symmetrical with said U-shaped spacer of said centralizer means and having a cross-sectional thickness, wherein the cross-sectional thickness of the spacer of said centralizer means is different than the cross-sectional thickness of the spacer of said handle means.
5. The proximal centralizer of Claim 4 wherein said handle means being adapted for engagement with said proximal end of the stem of said implant as an alternative to said centralizer means
6. The proximal centralizer of Claim 4 wherein the spacer of said centralizer means and said handle means are inclined relative
7. A method of spacing the proximal medial wall of a prosthetic hip implant a selected distance from the medial wall of a prepared intramedullary canal, said method comprising the steps of:
a. providing a spacing means having a generally U-shaped spacer member and a handle member integrally connected by temporary connector means, said spacer member adapted for engaging the proximal end of the stem of said implant and having a first cross-sectional thickness;
b. sliding said spacing means onto a distal end of said implant stem toward the proximal end of said stem until said spacing means is adjacent said proximal medial wall of said stem;
c. grasping said handle member and applying tension thereto to hold said spacing means in contact with said implant;
d. inserting said implant into said cement filled intramedullary canal until said spacing means is seated within said cement;
e. allowing said cement to cure slightly;
f. pivoting said handle means about said spacing means to break said temporary connector means for removal of said handle means.
a. providing a spacing means having a generally U-shaped spacer member and a handle member integrally connected by temporary connector means, said spacer member adapted for engaging the proximal end of the stem of said implant and having a first cross-sectional thickness;
b. sliding said spacing means onto a distal end of said implant stem toward the proximal end of said stem until said spacing means is adjacent said proximal medial wall of said stem;
c. grasping said handle member and applying tension thereto to hold said spacing means in contact with said implant;
d. inserting said implant into said cement filled intramedullary canal until said spacing means is seated within said cement;
e. allowing said cement to cure slightly;
f. pivoting said handle means about said spacing means to break said temporary connector means for removal of said handle means.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US65978491A | 1991-02-22 | 1991-02-22 | |
| US659,784 | 1991-02-22 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2059310A1 true CA2059310A1 (en) | 1992-08-23 |
Family
ID=24646830
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002059310A Abandoned CA2059310A1 (en) | 1991-02-22 | 1992-01-14 | Proximal centralizer with removable handle |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2059310A1 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5755793A (en) * | 1996-09-04 | 1998-05-26 | Bristol-Myers Squibb Company | Centralizer for a prosthetic implant |
| US5951606A (en) * | 1992-11-20 | 1999-09-14 | Burke; Dennis W. | Centering device for femoral implant and method and apparatus for implementation thereof |
| WO2003037192A1 (en) * | 2001-11-02 | 2003-05-08 | Eugene Sherry | Apparatus and methods for bone surgery |
| US7828805B2 (en) | 2006-02-02 | 2010-11-09 | Zimmer Technology, Inc. | Hip stem centralizer datum guide, and method |
-
1992
- 1992-01-14 CA CA002059310A patent/CA2059310A1/en not_active Abandoned
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5951606A (en) * | 1992-11-20 | 1999-09-14 | Burke; Dennis W. | Centering device for femoral implant and method and apparatus for implementation thereof |
| US6179877B1 (en) | 1992-11-20 | 2001-01-30 | Dennis W. Burke | Centering device for femoral implant and method and apparatus for implementation thereof |
| US5755793A (en) * | 1996-09-04 | 1998-05-26 | Bristol-Myers Squibb Company | Centralizer for a prosthetic implant |
| WO2003037192A1 (en) * | 2001-11-02 | 2003-05-08 | Eugene Sherry | Apparatus and methods for bone surgery |
| EA007729B1 (en) * | 2001-11-02 | 2006-12-29 | Интернэшнл Пэйтент Оунерз (Кайман) Лимитед | Apparatus for hip joint surgery |
| US7828805B2 (en) | 2006-02-02 | 2010-11-09 | Zimmer Technology, Inc. | Hip stem centralizer datum guide, and method |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |