United States Patent 1191
`Koshino
`
`USOO576625 1A
`[11] Patent Number:
`[45] Date of Patent:
`
`5,766,251
`Jun. 16, 1998
`
`[54] WEDGE-SHAPED SPACER FOR
`CORRECTION OF DEFQRMED
`
`8/1995 Steffee .................................... .. 623/17
`5,443,514
`5,571,190 11/1996 Ulrich eta], ............................ .. 623/17
`
`EXTREMITIES
`2451-112»
`[75] Invento? {:m?hisa
`aruyama _
`o nan- .
`Yokohama'shL Kanagawa 233~ Japan
`_
`_ _
`_
`[73] Asslgnce: Tomlhlsa Koshmo‘ Kanagawa‘ Japan
`
`[21] Appl. No.: 749,678
`[22] Filed:
`Nov. 15, 1996
`
`Related U.S.Applieation Data
`
`[63] Continuation-impart of Ser. No. 146,080, ?led as PCT/W93!
`00303’ Mal‘ 15’ 1993‘ abandmed-
`Foreign Applica?un priority Data
`
`[30]
`
`FOREIGN PATENT DOCUMENTS
`60-150756 11/1935 Japan.
`Primary Examiner-John G. Weiss
`Assistant Examiner—Bru0e E. Snow
`Attorney Agent, or Firm-Nikaido Marmelstein Murray &
`Oram LLP
`
`[57]
`
`ABSTRACT
`
`A wedge-shaped spacer usable for varus. valgus. ?exion.
`extension and derotalion osteotomies such as corrective
`osteotomy for femoral shaft deformity. supracondylar
`osteotomy of the femur. intraarticular osteotomy of the
`femur. intraarticular osteotomy of the tibia. high tibial
`osteotomy and subtuberosity osteotomy of the tibia. supra
`malleolar osteotorny of the tibia and. corrective osteotomy
`of the calcancus‘ is made of a
`hydroxyapa?t?
`Provided with a plurality of pfms having a pore sin? of 50
`to 250 pm and connected with each other and wlth the
`outside through a plurality of capillaries having a thickness
`of 0.5 to 5 pm. and having a compression strength of 300
`kg/cm2 and a porosity of 30 to 50%, and which spacer has
`at least one thorn-shaped projection extending outwardly in
`a projecting direction from at least one of the upper and
`lower surface thereof. and at least one hole extending from
`the upper surface to the lower surface therethrough in
`parallel to the projecting direction of the thorn-shaped
`Pmlectwn'
`
`5 Claims, 2 Drawing Sheets
`
`Japan .................................... n
`Mar. 13,
`[51] Int. Cl.6 ...................................................... .. A61F 2/28
`[52] Us Cl
`623/16 623/17_ 606/61
`[58]
`l'd
`’ 623/16’ 17 18
`9 0
`65 67‘ 69-72‘
`’
`‘
`_ 8
`
`a
`
`’
`
`‘
`
`'
`
`[56]
`
`.
`References cued
`US. PATENT DOCUMENTS
`1 I1 982 Pam
`4 309 777
`4:624:673 11/1986 Meyer ..... ..
`4,743,256
`5/1988 Brantigan .... ..
`5,306,307
`4/1994 Senter et a]. ..... ..
`
`623/17
`623/16
`623/17
`.. 623/17
`
`BEFORE OSTEOTOMY
`
`AFTER OSTEOTOMY
`
`DePuy Synthes Sales, Inc. & Depuy Synthes Sales, Inc.
`Exhibit 1008
`1 of 8
`
`

`
`US. Patent
`
`Jun. 16, 1998
`
`Sheet 1 0f 2
`
`5,766,251
`
`Fig.1
`
`BEFORE OSTEOTOMY
`
`AFTER OSTEOTOMY
`
`DePuy Synthes Sales, Inc. & Depuy Synthes Sales, Inc.
`Exhibit 1008
`2 of 8
`
`

`
`US. Patent
`
`Jun. 16, 1998
`
`Sheet 2 of 2
`
`5,766,251
`
`Fig.4
`
`BEFORE OSTEOTOMY
`
`AFTER OSTEOTOMY
`
`DePuy Synthes Sales, Inc. & Depuy Synthes Sales, Inc.
`Exhibit 1008
`3 of 8
`
`

`
`1
`WEDGE-SHAPED SPACER FOR
`CORRECTION OF DEFORMED
`EXTREMITIES
`
`CROSS REFERENCE TO RELATED
`APPLICATION
`
`This application is a continuation-in-part application of
`application Ser. No. 08/146080. ?led as PCT/JP93/00308.
`Mar. 15 . 1993 now abandoned and also claims priority under
`35 USC. §120 PCI‘ application Ser. No. PCI‘lJP93/00308.
`?led Mar. 15. 1993.
`
`TECHNICAL FIELD
`
`The present invention relates to a wedge-shaped spacer
`usable for correction of the deformed extremities due to
`bowlegs. knock knees. knee recurvaturn. Blount’s disease.
`rickets. osteonecrosis of the hips and the knees. Charcot
`joint. rheumatoid arthritis and osteoarthritis of the hips and
`the knees.
`More particularly. the present invention relates to a
`wedge-shaped spacer usable for the correction of the
`deformed extremities to a normal limb form and alignment
`by inserting into the osteotomized portion formed by varus.
`valgus. ?exion. extension and derotation osteotomies. such
`as corrective osteotomy for femoral shaft deformity. supra
`condylar osteotomy of the femur. intraarticular osteotomy of
`the femur. intraarticular osteotomy of the tibia. high tibial
`osteotomy. subtuberosity osteotomy of the tibia. and supra
`malleolar osteotomy of the calcaneus.
`
`BACKGROUND ARI‘
`Among bowlegs. knock knees. knee recurvatum. Blount’s
`disease. rickets. osteonecrosis of the hips and the knees.
`Charcot joint. rheumatoid arthritis and osteoarthritis of the
`hips and the knees. the osteoarthritis of the knee is a most
`common orthopaedic disease of middle-aged and older
`persons.
`In an opening high tibial osteotomy which is an example
`of a surgical treatment for the osteoarthritis of the knee. it is
`necessary to graft bonechips from the patient to ?ll an
`opened space of the osteotomy site. For this necessity. there
`is a problem that fresh bonechips have to be taken from other
`sites of the patient body by another surgery. Also. there are
`problems that the bonechips from the patient to be grafted
`cannot be obtained in a desired form and the bone chips are
`hard to be obtained in the infants and the osteoporotic
`elderly; complications such as bleeding and infection occur
`in the donor site of the bonechips; even when desired
`bonechips can be taken. the grafted bonechips are absorbed
`and ,the remaining bone portion collapses and thus an
`expected result of correction is very hard to be obtained; and
`a complication such as infection occurs in the osteotomy
`site. If homograft is used. further problems occur such as
`infections. AIDS. immunological troubles. Under the above
`mentioned circumstances. an attempt has been made to
`insert an arti?cial spacer material made by a metallic mate
`rial or another material into the osteotomy site and to correct
`the deformed bone to a normal shape. Also. a method of
`gradually opening the osteotomy site by an external fixation
`has been attempted.
`These conventional spacers have the following problems.
`(1) Since the conventional spacer is inserted into and ?xed
`in the osteotomy space only by a physical contact. the union
`of the operated bones is unable to be expected; and after the
`osteotomy. the patient is unable to start early exercises of
`
`5.766.251
`
`2
`joint motion and weightbearing walking; and a long reha
`bilitation time is required.
`(2) The conventional spacer does not organically react
`with an organism and is not absorbed by the organism. and
`thus no vital tissue is regenerated. and the spacer remains as
`a foreign body in the vital tissue and causes various com
`plications after the insertion.
`(3) Therefore. the use of the conventional spacer causes a
`high risk of occurring of fracture or infection.
`Also. surgical treatments using external ?xation cause a
`very high risk of infection. skin injury and palsy due to nerve
`damage. and these diseases are dil?cult to be cured. requir
`ing a long period of hospitalization.
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`DISCLOSURE OF THE INVENTION
`An object of the present invention is to provide a wedge
`shaped spacer usable for varus. valgus. ?exion. extension
`and derotation osteotomies such as corrective osteotomy of
`femoral shaft deformity. supracondylar osteotomy of the
`femur. intraarticular osteotomy of the femur. intraarticular
`osteotomy of the tibia. high tibial osteotomy and subtuber
`osity osteotomy of the tibia. supramalleolar osteotomy of the
`tibia. corrective osteotomy of the calcaneus. in surgical
`treatments for bowlegs. knock knees. knee recurvatum.
`Blount’s disease. rickets. osteonecrosis of the femoral head
`and the knee. Charcot joint. rheumatoid arthritis and osteoar
`thritis of the hip and the knee. The spacer of the present
`invention is able to get rid of the abovementioned disad
`vantages of the conventional spacer used in varus. valgus.
`?exion. extension and derotation osteotomies such as cor
`rective osteotomy for femoral shaft deformity. supracondy
`lar osteotomy of femur. intraarticular osteotomy of femur.
`intraarticular osteotomy of tibia. high tibial osteotomy and
`subtuberosity osteotomy of tibia. supramalleolar osteotomy
`of the tibia. and corrective osteotomy of the calcaneus. and
`is capable of being securely ?xed in the osteotomized
`portion between the fragments formed by the above
`mentioned osteotomies.
`Another object of the present invention is to provide a
`wedge-shaped spacer usable for varus. valgus. ?exion.
`extension and derotation osteotomies such as corrective
`osteotomy for femoral shaft deformity. supracondylar
`osteotomy of the femur. intraarticular osteotomy of the
`femur. intraarticular osteotomy of the tibia. high tibial
`osteotomy and subtuberosity osteotomy of the tibia. and
`supramalleolar osteotomy of the tibia. corrective osteotomy
`of the calcaneus. which is capable of promoting the union of
`the osteotomized site so as to greatly shorten the necessary
`rehabilitation time and to enable the patient to start the early
`exercise of joint motion and weightbearing walking after the
`osteotomy. holding the movable range of the operated joint
`in a good condition. to enable the surrounding bones to be
`generated by stimulating the activity of the osteoblasts so as
`to regenerate the vital tissue.
`In the present invention. the above-mentioned problems
`can be successfully solved by forming a wedgeshaped
`spacer. to be inserted into an osteotomized site formed by the
`varus. valgus. ?exion. extension and derotation osteotomies
`such as corrective osteotomy for femoral shaft deformity.
`supracondylar osteotomy of the femur. intraarticular
`osteotomy of the femur. intraarticular osteotomy of the tibia.
`high tibial osteotomy and subtuberosity osteotomy of the
`tibia. supramalleolar osteotomy of the tibia. and corrective
`osteotomy of the calcaneus. made of a specific sintered
`ceramic material having an excellent a?inity to organism
`and a speci?c porous structure and provided with at least one
`
`DePuy Synthes Sales, Inc. & Depuy Synthes Sales, Inc.
`Exhibit 1008
`4 of 8
`
`

`
`5.766.251
`
`25
`
`30
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`35
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`3
`thorn-shaped projection extending outwardly and at least
`one hole extending from the upper surface to the lower
`surface thereof through the spacer.
`Namely. the wedge- shaped spacer of the present invention
`usable for varus. valgus. ?exion. extension and derotation
`osteotomies such as corrective osteotorny for femoral shaft
`deformity. supracondylar osteotorny of the femur. intraar
`ticular osteotorny of the femur. intraarticular osteotorny of
`the tibia. high tibial osteotorny and subtuberosity osteotorny
`of the tibia. supramalleolar osteotorny of the tibia. and
`corrective osteotorny of the calcaneus. comprises a sintering
`product of hydroxyapatite which is provided with a plurality
`of pores having a pore size of 50 to 250 pm and connected
`with each other and with the outside through a plurality of
`capillaries having a thickness of 0.5 to 5 pm. and has a
`compression strength of 300 kglcmz and a porosity of 30 to
`50%. and has an upper surface and a lower surface. at least
`one thorn-shaped projection extending outwardly from at
`least one of the upper and lower surface. and at least one
`hole extending from the upper surface to the lower surface
`through the wedge-shaped spacer.
`In the wedge-shaped spacer of the present invention
`usable for varus. valgus. ?exion. extension and derotation
`osteotomies such as corrective osteotorny for femoral shaft
`deformity. supracondylar osteotorny of the femur. intraar
`ticular osteotorny of the femur. intraarticular osteotorny of
`the tibia. high tibial osteotorny and subtuberosity osteotorny
`of the tibia. supramalleolar osteotorny of the tibia. and
`corrective osteotorny of the calcaneus. the hole preferably
`has a polygonal cross-sectional pro?le.
`Also. in the wedge-shaped spacer usable for varus.
`valgus. ?exion. extension and derotation osteotomies such
`as corrective osteotomy for femoral shaft deformity. supra
`condylar osteotorny of the femur. intraarticular osteotorny of
`the femur. intraarticular osteotorny of the tibia. high tibial
`osteotorny and subtuberosity osteotorny of the tibia. and
`supramalleolar osteotorny of the tibia. corrective osteotorny
`of the calcaneus. the upper and lower surfaces of the
`wedge-shaped spacer are preferably inclined in relation to
`each other at an angle of 5 to 15 degrees.
`Further in the wedge-shaped spacer usable for varus.
`valgus. ?exion. extension and derotation osteotomies such
`as corrective osteotorny for femoral shaft deformity. supra
`condylar osteotorny of the femur. intraarticular osteotorny of
`the femur. intraarticular osteotorny of the tibia. high tibial
`osteotorny and subtuberosity osteotorny of the tibia. and
`supramalleolar osteotorny of the tibia. corrective osteotorny
`of the calcaneus. the thorn-shaped projection preferably has
`a height of from 2 to 4 mm.
`Furthermore. in the wedge-shaped spacer usable for
`varus. valgus. ?exion. extension and derotation osteotomies
`such as corrective osteotorny for femoral shaft deformity.
`supracondylar osteotorny of the femur. intraarticular
`osteotorny of the femur. intraarticular osteotorny of the tibia.
`high tibial osteotorny and subtuberosity osteotorny of the
`tibia. supramalleolar osteotorny of the tibia. and corrective
`osteotorny of the calcaneus. optionally. a plate member is
`attached to a head portion of the wedge-shaped spacer.
`
`4
`osteotorny and subtuberosity osteotorny of the tibia. supra
`malleolar osteotorny of the tibia. and corrective osteotorny
`of the calcaneus.
`FIG. 2 is a front view of the wedge-shaped spacer of FIG.
`1 usable for varus. valgus. ?exion. extension and derotation
`osteotomies such as corrective osteotorny for femoral shaft
`deformity. supracondylar osteotorny of the femur. intraar
`ticular osteotorny of the femur. intraarticular osteotorny of
`the tibia. high tibial osteotorny and submberosity osteotorny
`of the tibia. supramalleolar osteotorny of the tibia. and
`corrective osteotorny of the calcaneus.
`FIG. 3 is an explanatory view showing an employment
`condition of the wedge-shaped spacer of the present inven
`tion usable for varus. valgus. ?exion. extension and derota
`tion osteotomies such as corrective osteotorny for femoral
`shaft deformity. supracondylar osteotorny of the femur.
`intraatticular osteotorny of the femur. intraarticnlar
`osteotorny of the tibia. high tibial osteotomy and subtuber
`osity osteotorny of the tibia. supramalleolar osteotorny of the
`tibia. and corrective osteotorny of the calcaneus. when the
`spacer is employed for an opening high tibial osteotorny for
`the correction of bowlegs which is one of the most typical
`deformities in osteoarthritis of the knee.
`FIG. 4 is a front view of another embodiment of the
`wedge-shaped spacer of the present invention usable for
`varus. valgus. ?exion. extension and derotation osteotomies
`such as corrective osteotorny for femoral shaft deformity.
`supracondylar osteotorny of the femur. intraarticular
`osteotorny of the femur. intraarticular osteotorny of the tibia.
`high tibial osteotorny and subtuberosity osteotorny of the
`tibia. supramalleolar osteotorny of the tibia. and corrective
`osteotorny of the calcaneus.
`FIG. 5 is a front view of an embodiment of a correction
`angle-controlling spacer. and
`FIG. 6 is an explanatory view showing bow legs of the
`patient with osteoarthritis of the knee and its correction
`effect of the high tibial osteotorny using the wedge-shaped
`spacer of the present invention usable for varus. valgus.
`?exion. extension and derotation osteotomies such as cor
`rective osteotorny for femoral shaft deformity. supracondy
`lar osteotorny of the femur. intraarticular osteotorny of the
`femur. iutraarticular osteotorny of the tibia. high tibial
`osteotorny and subtuberosity osteotorny of the tibia supra
`malleolar osteotorny of the tibia. and corrective osteotorny
`of the calcaneus.
`
`BEST MODE OF CARRYING OUT THE
`INVENTION
`A plan view of an embodiment of the wedge-shaped
`spacer of the present invention usable for varus. valgus.
`?exion. extension and derotation osteotomies such as cor
`rective osteotorny for femoral shaft deformity. supracondy
`lar osteotorny of the femur. intraarticular osteotorny of the
`femur. intraarticular osteotorny of the tibia. high tibial
`osteotorny and subtuberosity osteotorny of the tibia. and
`supramalleolar osteotorny of the tibia. corrective osteotorny
`of the calcaneus.. is shown in FIG. I and a front view of the
`spacer of FIG. 1 is shown in FIG. 2.
`In FIGS. 1 and 2. a spacer 1 has a wedge-like form and
`is provided with an upper surface 2 and a lower surface 3
`opposite to each other and inclined away from each other.
`In the spacer l of the present invention. at least one.
`preferably 4 to 8 thorn-shaped projections 4 are formed on
`at least one. preferably both. of the upper and lower surface
`2 and 3 in such a manner that the projections 4 extend
`outward from the surface or surfaces of the spacer. The
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`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 is a plane view of an embodiment of the wedge
`shaped spacer of the present invention usable for varus.
`valgus. ?exion. extension and derotation osteotomies such
`as corrective osteotorny for femoral shaft deformity. supra
`condylar osteotorny of the femur. intraarticular osteotorny of
`the femur. intraarticular osteotorny of the tibia. high tibial
`
`65
`
`DePuy Synthes Sales, Inc. & Depuy Synthes Sales, Inc.
`Exhibit 1008
`5 of 8
`
`

`
`5.766.251
`
`15
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`20
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`25
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`5
`thorn-shaped projections are very effective to securely ?x
`the spacer to the bone fragments above and below the spacer
`within the osteotomized region and to enhance the bone
`union of the osteotomy site.
`The secure ?xation of the wedge-shaped spacer in the
`osteotomized region is very important for promoting the
`union of the bone tissue located above and below the
`wedge-shaped spacer with each other. which will be further
`explained hereinafter.
`The dimensions and form of the thorn-shaped projections
`of the wedge-shaped spacer material of the present invention
`are not restricted to speci?c values and a speci?c form and
`the dimensions are variable depending on the dimensions
`and form of the osteotomized portion. Generally. the thorn
`shaped projections have a height of 2 to 4 mm and are in any
`form such as a circular cone. trigonal pyramid. quadrangular
`pyramid. polygonal pyramid and elliptical cone. Preferably.
`the thorn-shaped projections have a sharpened top end so as
`to enable the spacer material to be ?rmly anchored to the
`bone ?'agments above and below the spacer in the osteoto
`mized region.
`Also. the wedge-shaped spacer l of the present invention
`usable for varus. valgus. ?exion. extension and derotation
`osteotomies such as corrective osteotomy for femoral shaft
`deformity. supracondylar osteotomy of the femur. inn'aar
`ticular osteotomy of the femur. intraarticular osteotomy of
`the tibia. high tibial osteotomy and subtuberosity osteotomy
`of the tibia. supramalleolar osteotomy of the tibia. and.
`corrective osteotomy of the calcaneus. is provided with at
`least one. preferably 1 to 6 holes 5 through which the upper
`surface 2 and lower surfaces 3 are connected to each other.
`The holes 5 are used for insertion of the small bonechips of
`the patient thereinto which are able to be obtained around the
`osteotomy site. When a wedgeshaped spacer 1 having the
`small bonechips inserted into the holes Sis inserted into the
`osteotomized portion. the growth of bone is accelerated
`within a relatively short period so that the new bone forma
`tion of the inserted bonechips and the bone tissue located
`above and below the wedge-shaped spacer 1 are accelerated
`and these bones are united easily with each other. Further.
`the grafted bonechips inserted into the holes rapidly gow
`and are united with each other. Due to the abovementioned
`union of the newly formed bones. the stability of the
`wedge-shaped spacer 1 in the osteotomized portion is
`enhanced so as to ensure the regeneration of the surrounding
`vital tissue. reformation and union of the bone.
`There are no speci?c limitations to the form and dimen
`sions of the holes 5. The form and dimensions of the holes
`5 may be appropriately established. Nevertheless. the holes
`5 preferably have a polygonal cross-sectional pro?le. more
`preferably a rectangular cross-sectional pro?le. When the
`cross-sectional pro?le of the hole of the wedge-shaped
`spacer is polygonal. the small bonechips of the patient.
`which are obtained from the bone tissue around the
`osteotomy site and inserted into the hole. grow in the hole
`of the corresponding cross-sectional pro?le and are con
`nected to the bone portions located above and below the
`spacer. and thus the spacer cannot rotate around the resultant
`shaft consisting of the grown bonechips with the polygonal
`cross-section. and can be maintained at the desired angle of
`correction without deviation. Also. in the case of derotation
`osteotomy. the tissues such as the muscle. the tendon. the
`ligament and the periosteum around the osteotomy site tend
`to be restored to the original state and thus rotational
`deformity tends to be recurred. The polygonal cross-section
`of the hole of the spacer e?ectively prevent the restoration
`of the axial rotation of the bone. The capability of the hole
`
`6
`for stabilizing the osteotomized bones against restoration
`becomes highest when the hole has a rectangular cross
`sectional pro?le.
`Polygons other than a rectangle are closer to a circle and
`thus may allow the rotationally osteotomized bone parts to
`be slightly restored.
`The corners of the holes with the polygonal cross-section
`are preferably slightly rounded. If sharply angled (not
`rounded). portions of the bonechip of the patient inserted
`into the hole with sharp corners have a reduced blood
`circulation in those corners and thus the bone tissue may
`have corner osteonecrosis.
`The wedge-shaped spacer usable for varus. valgus.
`?exion. extension and derotation osteotornies such as cor
`rective osteotomy for femoral shaft deformity. supracondy
`lar osteotomy of the femur. intraarticular osteotomy of the
`femur. intraarticular osteotomy of the tibia. high tibial
`osteotomy and subtuberosity osteotomy of the tibia. and
`suprarnalleolar osteotomy of the tibia. corrective osteotomy
`of the calcaneus. are made of a sintering product of
`hydroxyapatite which is one of bioactive ceramics. The
`sintering product of hydroxyapatite usable for the present
`invention has a plurality of pores having a pore size of 50 to
`250 um. preferably 70 to 200 pm and connected to each
`other and to the outside thereof through a plurality of
`capillaries having a thickness of 0.5 to 5 mm preferably 1 to
`3 pm. These pores and capillaries can receive thaein cells
`for the regeneration of the bone and prevent invasion of
`harmful substances. so as to promote the new formation of
`the bone and the regeneration of the surrounding vital
`tissues. Also. the spacer made by the above-mentioned
`porous hydroxyapatite sintering product can promote the
`union of the bone parts located above and below the Wedge
`shaped spacer with each other.
`The hydroxyapatite comprises. as a principal component.
`a compound of the composition formula: Ca5(PO4)3OH or
`Cam(P04)6(OH)2. and some Ca atoms are optionally
`replaced by at least one member selected from. for example.
`Sr. Ba. Mg. Fe. Al. Y. La. Na. K and H. Also. a portion of
`(P04) groups is optionally at least one member selected
`from V04. B03. 80... CO3. and SD... The hydroxyapatite
`may be in the form of an ordinary crystal. isomorphism type
`solid solution. substitution type solid solution. or penetration
`type solid solution. Also. the hydroxyapatite may have a
`structure with a non-quantum theoretical lattice defect.
`The pores formed in the sintered hydroxyapatite spacer
`are preferably in the forms of true spheres or balls. When the
`porous spacer is inserted into the osteotomized portion of the
`bone. the pores provide living spaces for biologically acti
`vate osteoclasts and osteoblasts. If the pore size is less than
`50 um or more than 250 um. the resultant pores cannot be
`suitable living spaces for the above-mentioned cells. Also.
`pores having a size of more than 250 um cause the resultant
`wedge-shaped spacer to exhibit a signi?cantly reduced
`mechanical strength. and thus. after the osteotomy. the
`patient cannot start early walking with weightbearing. and
`the necessary rehabilitation time after the surgery cannot be
`shortened.
`The capillaries formed in the sintered hydroxyapatite
`spacer e?’ectively connect the pores to each other and to the
`outside of the spacer. and thus the osteoclasts. osteoblasts.
`red blood cells and body ?uid can freely penetrate into the
`spacer through the capillary. and development of blood
`capillaries is promoted. However. the capillaries formed in
`the sintered hydroxyapatite spacer have a thickness of 0.5 to
`5 pm. the osteoclasts and collagen ?bers are hard to in?ltrate
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`DePuy Synthes Sales, Inc. & Depuy Synthes Sales, Inc.
`Exhibit 1008
`6 of 8
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`into the spacer through the capillaries. and thus undesirable
`irregular growth of the collagen ?bers can be prevented.
`As mentioned above. the wedge-shaped spacer of the
`present invention usable for varus. valgus. ?exion. extension
`and derotation osteotomies such as corrective osteotomy for
`femoral shaft deformity. supracondylar osteotomy of the
`femur. intraarticular osteotomy of the femur. intraarticular
`osteotomy of the tibia. high tibial osteotomy and subtuber
`osity osteotomy of the tibia. supramalleolar osteotomy of the
`tibia. corrective osteotomy of the calcaneus. comprises a
`sintering product of hydroxyapatite which is a bioactive
`ceramic and has a speci?c porous structure. Therefore, the
`wedge-shaped spacer of the present invention can selec
`tively receive the cells which serve as the seed cells for the
`new bone formation while preventing the in?ltration of the
`harmful substances into the spacer. so that the growth of
`cells contributory to new bone formation is promoted. the
`regeneration of vital tissues. namely replacement of arti?cial
`implant by vital tissue is promoted. and the union of the bone
`parts located above and below the spacer to each other is
`ensured.
`The wedge-shaped spacer of the present invention usable
`for varus. valgus. ?exion. extension and derotation osteoto
`mies such as corrective osteotomy for femoral shaft
`deformity. supracondylar osteotomy of the femur. inn-aar
`ticular osteotomy of the femur. intraarticular osteotomy of
`the tibia. high tibial osteotomy and subtuberosity osteotomy
`of the tibia. supramalleolar osteotomy of the tibia. and
`corrective osteotomy of the calcaneus. has a compression
`strength of at least 300 kglcmz. preferably 400 to 500
`kg/cm2 and the sintering hydroxyapatite product has a
`porosity of 30 to 50%. preferably 34 to 45%. Namely. since
`the wedge~shaped spacer of the present invention usable for
`varus. valgus. ?exion. extension and derotation osteotomies
`such as corrective osteotomy for femoral shaft deformity.
`supracondylar osteotomy of the femur. intraarticular
`osteotomy of the femur. intraarticular osteotomy of the tibia.
`high tibial osteotomy and subtuberosity osteotomy of the
`tibia. supramalleolar osteotomy of the tibia. and corrective
`osteotomy of the calcaneus. is inserted into the osteotomy
`site. the compression sn'ength of the spacer must be 300
`kg/cm2 or more. If it is not. the patient cannot start early
`walking exercise. with weightbearing until the osteotomized
`sites are completely replaced by newly formed bone. and
`thus the necessary rehabilitation time cannot be minimized.
`To keep the compression strength of the sintering product
`of hydroxyapatite at a level of 300 kglcm2 or more. the
`porosity of the sintering product must be adjusted to 50% or
`less. Also. to provide the abovementioned living spaces for
`biologically activating the osteoclasts and osteoblasts and to
`promote the new bone formation. it is very important to
`adjust the porosity of the sintering product of hydroxyapatite
`to 30% or more.
`There are no speci?c limitations to the dimensions and
`form of the wedge-shaped spacer of the present invention
`usable for varus. valgus. ?exion. extension and derotation
`osteotomies such as corrective osteotomy for femoral shaft
`deformity. supracondylar osteotomy of the femur. intraar
`ticular osteotomy of the femur. intraarticular osteotomy of
`the tibia. high tibial osteotomy and subtuberosity osteotomy
`of the tibia. supramalleolar osteotomy of the tibia. and
`corrective osteotomy of the calcaneus.
`The dimensions and form of the spacer are appropriately
`set forth in consideration of the dimensions and form of the
`osteotomy site of the bone. Nevertheless. the wedge-shaped
`spacer material of the present invention generally has a
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`45
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`55
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`65
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`25
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`length L of 30 to 80 mm. a largest width W1 of 10 to 25 mm.
`a smallest width W2 of 5 to 15 mm. a largest thickness of 3
`to 15 mm and a smallest thickness of l to 3 mm.
`The sintering product of hydroxyapatite usable for the
`present invention can be produced. for example. by mixing
`a desired amount of hydroxyapatite particles with organic
`synthetic resin particles having a particle size of 50 to 250
`pm in an amount corresponding to the desired porosity of the
`sintering product. shaping the mixture into desired form and
`dimensions. heating the resultant shaped article at a tem
`perature of 200° to 800° C. to decompose away the organic
`synthetic resin particles and ?nally sintering the heated
`article at a temperature of 800° C. to 1350° C.. preferably
`1000° C. to 1200° C. in an oxygen-containing oxidative
`atmosphere.
`In the wedge-shaped spacer of the present invention
`usable for varus. valgus. ?exion. extension and derotation
`osteotomies such as corrective osteotomy for femoral shaft
`deformity. supracondylar osteotomy of the femur. intraar
`ticular osteotomy of the femur. intraarticular osteotomy of
`the tibia. high tibial osteotomy and subtuberosity osteotomy
`of the tibia. supramalleolar osteotomy of the tibia. and
`corrective osteotomy of the calcaneus. the upper surface 2 is
`inclined from the lower surface 3 at an inclination angle 9.
`The inclination angle 6 is preferably in the range from 5 to
`15 degrees. When the inclination angle 0 is within the
`above-mentioned range. the resultant spacer can be easily
`inserted into an osteotomized space of the bone and the
`opening angle (correction angle) of the osteotomy site can
`be adequately controlled by regulating the insertion angle of
`the spacer.
`Referring to FIG. 3. a portion 6a of the bone 6 is
`osteotomized and opened. and a wedge-shaped spacer l of
`the present invention usable for varus. valgus. ?exion.
`extension and derotation osteotomies such as corrective
`osteotomy for femoral shaft deformity. supracondylar
`osteotomy of the femur. intraarticular osteotomy of the
`femur. intraarticular osteotomy of the tibia. high tibial
`osteotomy and subtuberosity osteotomy of the tibia. supra
`malleolar osteotomy of the tibia. and corrective osteotomy
`of the calcaneus. is inserted into the osteotomized and
`opened 60 space of the bone 6. a head portion of the spacer
`1 is held down by a metal or ceramic plate 7. and this plate
`7 is ?xed to the bone 6 by screws 8.
`As shown in FIG. 4. the wedge-shaped spacer of the
`present invention usable for varus. valgus. ?exion. extension
`and derotation osteotomies such as corrective osteotomy for
`femoral shaft deformity. supracondylar osteotomy of the
`femur. intraarticular osteotomy of the femur. intraarticular
`osteotomy of the tibia. high tibial osteotomy and subtuber
`osity osteotomy of the tibia. supramalleolar osteotomy of the
`tibia. and corrective osteotomy of the calcaneus. is option
`ally provided with a plate member 10 attached to a head
`portion 9 thereof having a largest thickness. The plate
`member 10 extends from the head portion 9 of the wedge
`shaped spacer at a desired length (or area) in a desired
`direction or directions. When the wedge-shaped spacer is
`inserted into the osteotomized and opened space of the bone.
`the plate member 10 can be ?xed to the bone by screws. and
`thereby the wedge-shaped spacer can be stabilized as a
`whole at a desired position in the bone.
`Where the wedge-shaped spacer of the present invention
`usable for varus. valgus. ?exion. extension and derotation
`osteotomies such as corrective osteotomy for femoral shaft
`deformity. supracondylar osteotomy of the femur. intraar
`ticular osteotomy of the