# US 5,702,474 A · Coaxial ligamented hip prosthesis

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- Number: US 5,702,474 A
- Document ID: US5702474A
- Status: Granted
- Kind: A
- Application number: 08/589,644
- Filed: 1996-01-22
- Granted: 1997-12-30
- Earliest claimed: 1996-01-22
- Inventors: Robert McCandliss
- Web page: https://patentgrep.com/patent/US5702474A

## CPC

- A61B 17/7098: {wherein the implant is permeable or has openings, e.g. fenestrated screw (hollow surgical screws A61B17/864)}
- A61F 2/30742: {Bellows or hose-like seals; Sealing membranes (A61B17/8808 takes precedence; sealing membranes for retaining bone substitute A61F2/2846)}
- A61F 2/32: for the hip
- A61B 17/8875: {Screwdrivers, spanners or wrenches}
- A61F 2/08: Muscles; Tendons; Ligaments
- A61F 2/30744: {End caps, e.g. for closing an endoprosthetic cavity}
- A61F 2/3662: {Femoral shafts}
- A61F 2/367: {Proximal or metaphyseal parts of shafts (trochanteric devices connected to said proximal parts A61F2/30739)}
- A61F 2/488: {Means for detecting or monitoring wear}
- A61F 2002/30143: {hexagonal}
- A61F 2002/30154: {square}
- A61F 2002/30332: {Conically- or frustoconically-shaped protrusion and recess}
- A61F 2002/30405: {made by screwing complementary threads machined on the parts themselves}
- A61F 2002/30408: {Conical threadings}
- A61F 2002/30433: {using additional screws, bolts, dowels, rivets or washers e.g. connecting screws}
- A61F 2002/30448: {using adhesives}
- A61F 2002/30462: {retained or tied with a rope, string, thread, wire or cable}
- A61F 2002/30469: {using band clamps}
- A61F 2002/30495: {using a locking ring}
- A61F 2002/30507: {using a threaded locking member, e.g. a locking screw or a set screw}
- A61F 2002/30546: {for adjusting elasticity, flexibility, spring rate or mechanical tension}
- A61F 2002/30589: {Sealing means}
- A61F 2002/30593: {hollow}
- A61F 2002/30594: {slotted, e.g. radial or meridian slot ending in a polar aperture, non-polar slots, horizontal or arcuate slots}
- A61F 2002/30662: {with rotation-limiting means}
- A61F 2002/30682: {Means for preventing migration of particles released by the joint, e.g. wear debris or cement particles}
- A61F 2002/30683: {Means for collecting wear particles in a hollow cavity inside the prosthesis}
- A61F 2002/30688: {Means for allowing passage or sliding of tendons or ligaments}
- A61F 2002/30795: {Blind bores, e.g. of circular cross-section}
- A61F 2002/30939: {Means for modifying the geometry of articulating surfaces, e.g. for compensating excessive clearance caused by wear}
- A61F 2002/3241: {having a ring, e.g. for locking the femoral head into the acetabular cup}
- A61F 2002/3401: {with radial apertures, e.g. radial bores for receiving fixation screws}
- A61F 2002/3469: {with non-radial inner bores or canals}
- A61F 2002/3621: {pierced with a longitudinal bore}
- A61F 2002/3647: {pierced with a longitudinal bore}
- A61F 2002/365: {Connections of heads to necks}
- A61F 2220/0025: Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
- A61F 2220/0033: made by longitudinally pushing a protrusion into a complementary-shaped recess, e.g. held by friction fit
- A61F 2220/0041: using additional screws, bolts, dowels or rivets, e.g. connecting screws
- A61F 2220/005: using adhesives
- A61F 2220/0075: sutured, ligatured or stitched, retained or tied with a rope, string, thread, wire or cable
- A61F 2230/0017: Angular shapes
- A61F 2230/0021: square
- A61F 2250/0012: for adjusting elasticity, flexibility, spring rate or mechanical tension
- A61F 2310/00011: Metals or alloys
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- 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 (dental prosthetics A61C)

## Abstract

A hip prosthesis is disclosed herein intended to be fitted into a skeletal pelvis socket and which has a replacement socket that includes a metal semi-spherical acetabulum base with a plastic acetabulum liner for movably holding a spherical ball against the liner by a ligament rod. The rod passes through a head of a stem implanted into a femur and terminates with a ligament anchor plate fitted in the acetabulum base via an eyelet and pin connection. A tensioning nut is carried on the stem head in threadable connection with the rod. A conical cutout in the spherical ball permits movement of the ball with the apex of the cone at the center of the spherical ball under adjustable tensioning of the rod. A Wear compensation system is included by incorporating an open passageway in the base which communicates with a blister in the liner for accommodating the introduction of cement to compensate for wear. A boot of mesh material encloses portions of the base, liner and the ball.

## Claims

### Claim 1

A hip socket prosthesis for disposal between a skeletal femur and a pelvis socket comprising:
a metal semi-spherical acetabulum base;
a spherical ball;
a plastic acetabulum liner disposed in said metal semi-spherical acetabulum for movably holding said spherical ball;
an elongated stem having a head laterally projecting into securement with said spherical ball; and
a ligament rod movably carried on said head and secured to said metal semi-spherical acetabulum base for movably holding said spherical ball.

### Claim 2 (depends on 1)

The invention as defined in claim 1 wherein:
said spherical ball includes a recess occupied by said head and a conical opening coaxially disposed with respect to said head having its apex terminating at said head and outwardly flaring to terminate opposite said lining; and
said ligament rod having opposite ends separated by a midsection movable through said head;
one end of said ligament rod passing through said conical recess to be anchored with said metal semi-spherical acetabulum base.

### Claim 3 (depends on 2)

The invention as defined in claim 2 wherein:
said end of said ligament rod opposite to said one end is externally exposed within said head, and
means operably coupled to said end and bearing against said head for selectively and manually moving said head about said ligament rod to urge said spherical ball into engagement with said liner.

### Claim 4 (depends on 3)

The invention as defined in claim 3 wherein:
said moving means is a tensioning nut for adjusting the engagement force of said spherical ball against said liner.

### Claim 5 (depends on 4)

The invention as defined in claim 4 including:
a boot of mesh material carried between said head and said metal semi-spherical acetabulum base about said spherical ball for collecting debris worn from said liner, said base and said Spherical ball during use.

### Claim 6 (depends on 5)

The invention .as defined in claim 5 including:
a wear compensation means having an expandable portion provided in said liner; and
said base having an open passageway leading to said expandable portion for introducing an injected cement into said expandable portion urging said liner into forcible engagement with said spherical ball.

### Claim 7 (depends on 6)

The invention as defined in claim 6 wherein:
said liner includes a central opening accommodating said ligament rod and said anchoring connection with said metal semi-spherical acetabulum base.

### Claim 8

A replacement hip prosthesis for fitting into a skeletal pelvis socket comprising:
an elongated stem with a laterally projecting held;
an arcuate socket base with an internal liner;
a ball secured to said head and bearing against said liner; and
a ligament rod carried on said head and slidably extending through said ball terminating in an anchored connection with said socket base.

### Claim 9 (depends on 8)

The invention as defined in claim 8 including:
tension adjustment means disposed between said ligament rod and said head for selectively adjusting the bearing force applied by said ball to said liner.

### Claim 10 (depends on 8)

The invention as defined in claim 8 including:
a flexible mesh boot having opposite ends secured to said head and to said socket base respectively for collecting debris dislodged from said liner, said ball and said socket base during use.

### Claim 11 (depends on 8)

The invention as defined in claim 8 including:
means cooperating between said socket base and said liner for expanding said liner into close load bearing relationship with said ball.