Source: http://www.google.com/patents/US5549693?dq=5,960,411
Timestamp: 2015-05-06 02:37:34
Document Index: 619242038

Matched Legal Cases: ['art.\n8', 'art 18', 'art 18', 'art 18', 'art 18', 'art 18']

Patent US5549693 - Cotyloidal prostheses - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsA prosthesis has a ceramic part to cooperate with a spherical head. This ceramic part is a ring whose inside surface is part of a sphere. The prosthesis is suitable for coxofemoral joints....http://www.google.com/patents/US5549693?utm_source=gb-gplus-sharePatent US5549693 - Cotyloidal prosthesesAdvanced Patent SearchPublication numberUS5549693 APublication typeGrantApplication numberUS 08/258,827Publication dateAug 27, 1996Filing dateJun 13, 1994Priority dateJun 17, 1993Fee statusLapsedAlso published asDE69407667D1, DE69407667T2, EP0630624A1, EP0630624B1Publication number08258827, 258827, US 5549693 A, US 5549693A, US-A-5549693, US5549693 A, US5549693AInventorsChristiane Roux, Michel PequignotOriginal AssigneeRoux; Christiane, Pequignot; MichelExport CitationBiBTeX, EndNote, RefManPatent Citations (16), Referenced by (29), Classifications (28), Legal Events (5) External Links: USPTO, USPTO Assignment, EspacenetCotyloidal prostheses
US 5549693 AAbstract
A prosthesis has a ceramic part to cooperate with a spherical head. This ceramic part is a ring whose inside surface is part of a sphere. The prosthesis is suitable for coxofemoral joints.
1. Cotyloidal prosthesis, in particular for coxofemoral joints, comprising cup means having a contact surface for ball-and-socket contact with a ceramic spherical head, said cup means including a ceramic socket ring having a part-spherical inside surface defining said contact surface of said cup means, said cup means further comprising a plastic material cup member having an opening for introducing the part-spherical head, said cup member carrying said ceramic socket ring near the opening of the cup member, further comprising a metal liner lining said plastic material cup member, said metal lining not defining any part of said contact surface of said cup means.
2. Cotyloidal prosthesis according to claim 1 wherein said cup member has an inner surface radially outerwardly spaced from a sphere defined by said part-spherical inner surface of said ceramic socket ring.
3. Cotyloidal prosthesis according to claim 2 wherein said cup member has an inner surface which is also part-spherical, the radius of the part-spherical surface of said cup member being greater than that of the part-spherical surface of said ceramic socket ring.
4. Cotyloidal prosthesis assembly according to claim 3 and further comprising a fixing member surrounding and secured to the cup means of the cotyloidal prosthesis.
5. Cotyloidal prosthesis according to claim 1 further comprising an elastic material ring interposed between said cup member and said ceramic socket ring for enhancing damping properties of the prosthesis.
6. Cotyloidal prosthesis according to claim 1 wherein said ceramic socket part is in force-fit engagement with the plastic material cup.
7. Cotyloidal prosthesis according to claim 1 further comprising clipping means disposed between said plastic material cup member and said ceramic socket part.
8. Cotyloidal prosthesis, in particular for coxofemoral joints, comprising cup means having a contact surface for ball-and-socket contact with a ceramic spherical head, said cup means including a ceramic socket ring having a part-spherical inside surface defining said contact surface of said cup means, said cup means having an opening for introducing the part-spherical head, said ceramic socket ring having a front surface lying in a plane slightly set back relative to an equatorial plane of a sphere defined by the part-spherical inside surface, such that the ceramic socket ring lies entirely to one side of the equatorial plane remote from said opening.
9. Cotyloidal prosthesis according to claim 8 wherein said ceramic socket ring has an axis, the height of said ceramic socket ring, measured parallel to the axis, being at most equal to one-half the radius of a sphere defined by the part-spherical inside surface.
10. Cotyloidal prosthesis according to claim 9 wherein the height of said ceramic socket ring is between one-third and one-half the radius of the sphere defined by the part-spherical inside surface.
11. Cotyloidal prosthesis according to claim 8 wherein said ceramic socket part has front and rear surfaces lying in spaced parallel planes.
12. Cotyloidal prosthesis according to claim 8 wherein said ceramic socket ring has a cylindrical outer surface.
13. Cotyloidal prosthesis according to claim 8 wherein said ceramic socket ring has a cylindrical outer surface, and a hooping band bears along substantially the entire height of the cylindrical outer surface of the ceramic socket ring to increase the mechanical strength of the ceramic socket ring.
Prior art coxofemoral joint prostheses have two complementary parts: namely a hemispherical cup or cotyle adapted to be fixed directly or indirectly by means of a fixing member to the cotyloid cavity of the iliac bone of the patient and a ball-shaped spherical head at the end of a stem adapted to be inserted into the MNO of the patient.
Most coxofemoral joint prostheses are for older patients, in whom there is a particular tendency for eventual detachment of the cup when it is made from ceramic, this being attributable, for example, to poor attachment of the ceramic to the bone tissue in this case. For this reason, ceramic cups are at present usually employed only for younger patients whose bone tissue seems better able to accommodate this material, probably because the damping of normal impacts, such as those occasioned on walking, is better in these patients.
Apart from the inevitable production of polyethylene debris which is currently suspected of causing bone damage, coxofemoral joint prostheses including a synthetic material cup have the drawback of a shorter service life than those in which the cup is made from ceramic.
Various studies have shown that, regardless of the materials from which they are made, the spherical head moves progressively deeper into the cup, partly because of cold flow of the synthetic material of the latter and partly because the spherical head wears away the synthetic material.
Incidentally, this is the reason why coxofemoral joint prostheses using a ceramic-ceramic rubbing pair, i.e. in which the cup and the spherical head are both made of ceramic, are increasingly attracting interest, given the requirement for a long service life in younger patients.
A general object of the present invention is a cotyloidal prosthesis which, by virtue of improvements to the use of a ceramic-ceramic rubbing pair, provides in a very simple manner an advantageous compromise between coxofemoral joint prostheses with a ceramic cup and those with a synthetic material cup, and which additionally has further advantages.
It is based on the observation that, in bipeds, the parts of the bone components concerned, namely the cotyloid cavity and the femoral head, which are actually loaded are in practise usually restricted to a small portion of the joint crescent, substantially equivalent to the roof only of the cotyloid cavity.
The present invention consists in a cotyloidal prosthesis, in particular for coxofemoral joints, of the kind including a ceramic part adapted to cooperate with a spherical head, said ceramic part comprising a ring having a part-spherical inside surface, that is this surface is part of a sphere.
The invention thus divides functions between a ceramic internal part, in this instance the ring, whose function is to cooperate with the spherical head to make the joint, and an external part such as a synthetic material cup whose only function is to connect the ring to the cotyloid cavity, being fixed to the latter in the usual way and either directly, for example by cementing it in place, or indirectly, for example by means of a metal fixing member.
The quantity of ceramic used is therefore reduced very substantially, by a factor of 3 to 6, for example. Also, the cost of machining and polishing the ring is reduced as compared with a cup.
If a fixing member is used the presence of the ceramic ring has the advantage of providing as much room as is required on the external surface of the synthetic material cup for recesses to accommodate the fixing means for attaching the fixing member to the cotyloid cavity, with no risk that the resulting localized thinning of the cup at these locations leading, through cold flow and wear, to direct rubbing of the spherical head on the fixing means, as could happen if there were no such ring.
Given its reduced thickness, which provides the necessary room in the radial direction, the ceramic ring of the invention is advantageously externally hooped to increase its mechanical strength and in particular its resistance to impact and bursting.
The radial stresses due to hooping effectively oppose the propagation of microcracks, such as the cracks that can occur in ceramics, especially due to the action of alternating stresses and/or in the presence of a wetting liquid, as in the case of a joint prosthesis.
Given its relatively small dimensions, it is feasible to make the ceramic ring from a single crystal, cut on the appropriate axis, rather than by sintering, which would eliminate any risk of grain separation and the consequences thereof inherent to manufacture by sintering.
The features and advantages of the invention emerge from the following description given by way of example with reference to the appended diagrammatic drawings.
Referring to the figures, the cotyloidal prosthesis 10 in accordance with the invention includes, in the known manner, a synthetic material cup 11 adapted to be implanted in a cotyloid cavity (not shown) and to cooperate, internally, with a spherical head 12 shown in chain-dotted outline in FIG. 2.
The cotyloid cavity is in this case part of the ilium of the patient. The spherical head 12 is at the end of a stem 14 inserted in and fastened to the femur of the patient.
The spherical head 12 is a ceramic ball, for example an alumina ceramic ball. It is appropriately fastened to the stem 14, for example by means of a conical interference fit, and the stem 14 is made from metal, for example.
The cup 11 is made from high-density polyethylene, for example, and for fixing it to the cotyloid cavity it is associated with a fixing member 15 disposed around it, as shown diagrammatically in chain-dotted outline in FIG. 2, and which is also generally cup-shaped. It is clipped into this member, for example.
To be more precise, in these embodiments the front surface 20 of the ring constituting the ceramic part 18 lies in a plane which is slightly set back relative to the equatorial plane P of the sphere S perpendicular to the axis A, between this equatorial plane P and the far end 19 of the cup 11.
In the embodiments shown, the height H' of this cylindrical bearing surface 27 is slightly greater than that H of the ring constituting the ceramic part 18 with the result that the front surface 20 of the latter is set back relative to the opening 16 of the cup 11.
Starting from the ring constituting the ceramic part 18, and therefore from the transverse shoulder 26, the inside surface 28 of the cup 11 is preferably spaced from the sphere S of which the inside surface 19 of the ring constituting the ceramic part 18 is part.
In the embodiment shown the inside surface 28 of the cup 11 is part of a sphere S' concentric with the sphere S and the diameter R' of the sphere S' is greater than that R of the sphere S.
Alternatively, as shown in FIGS. 5 and 6, the cup 11 has an annular bead 34 with a frustoconical outside surface projecting from its cylindrical bearing surface 27, starting from its opening 16, which clips over the ring constituting the ceramic part 18.
In particular, although the synthetic material cup has benefits of its own, in particular its damping capability and the ease with which it provides the necessary adaptation between the ring constituting the ceramic part and the external fixing member, this ring can be carried directly by the fixing member, being directly hooped by the latter.
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assembly and joint member thereforUS8323346Nov 16, 2007Dec 4, 2012Scyon Orthopaedics AgWear-reducing geometry of articulations in total joint replacementsUS8652213Jun 29, 2011Feb 18, 2014DePuy Synthes Products, LLCAspheric hip bearing coupleUS8715364 *Feb 5, 2007May 6, 2014DePuy Synthes Products, LLCAspheric hip bearing coupleUS8790412Sep 30, 2011Jul 29, 2014Smith & Nephew, Inc.Containment system for constraining a prosthetic componentUS8840676 *May 7, 2010Sep 23, 2014Smith & Nephew, Inc.Modular trial heads for a prostheticUS9005306Nov 7, 2007Apr 14, 2015Biomedflex, LlcMedical Implants With Compliant Wear-Resistant SurfacesUS9005307Dec 5, 2011Apr 14, 2015Biomedflex, LlcProsthetic ball-and-socket jointUS20090326669 *Aug 6, 2007Dec 31, 2009Roman PreussInsertion of vibration-damping elements in prosthetic systems for the manipulation and damping of natural frequenciesUS20120239160 *May 7, 2010Sep 20, 2012Smith & Nephew, Inc.Modular trial heads for a prostheticUS20140200675 *Jul 18, 2012Jul 17, 2014Hip Innovation Technology, LLCLined Femoral CupWO2011073351A2Dec 16, 2010Jun 23, 2011Slobodan TepicPartial hip prosthesisWO2013030668A1Aug 31, 2012Mar 7, 2013Scyon Orthopaedics AgWear-reducing ring for articulations in total joint replacements* Cited by examinerClassifications U.S. Classification623/22.14International ClassificationA61F2/30, A61F2/32, A61L27/10, A61F2/36, A61F2/00, A61F2/34Cooperative ClassificationA61F2310/00017, A61F2002/30685, A61F2002/3414, A61F2002/3448, A61F2310/00203, A61F2002/3411, A61F2002/305, A61F2002/3625, A61F2/32, A61F2002/3241, A61F2002/30563, A61F2002/30489, A61F2310/00023, A61F2220/0025, A61F2/34, A61F2002/30968, A61L27/105, A61F2002/3225, A61F2002/3611European ClassificationA61L27/10A, A61F2/34Legal EventsDateCodeEventDescriptionOct 26, 2004FPExpired due to failure to pay maintenance feeEffective date: 20040827Aug 27, 2004LAPSLapse for failure to pay maintenance feesMar 17, 2004REMIMaintenance fee reminder mailedFeb 25, 2000FPAYFee paymentYear of fee payment: 4Apr 19, 1999ASAssignmentOwner name: TEXAS INSTRUMENTS INCORPORATED, TEXASFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:STASZEWSKI, ROBERT B.;SPAGNA, FULVIO;REEL/FRAME:009911/0709;SIGNING DATES FROM 19990405 TO 19990413RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services