Unbalanced prosthetic device for providing side-dependent twisting-rotational axial-loading coupling

• US 6,299,649 B1
• Filed: 07/26/1999
• Issued: 10/09/2001
• Est. Priority Date: 06/22/1996
• Status: Expired due to Fees

• Current Assignee: Fu-Kuo Chang, Hasan Yildiz, Stuart B. Goodman
• Original Assignee: Fu-Kuo Chang, Hasan Yildiz, Stuart B. Goodman
• Inventors: Chang, Fu-Kuo, Goodman, Stuart B., Yildiz, Hasan
• Primary Examiner(s): Prebilic, Paul B.
• Application Number:
  US09/360,926
• Time in Patent Office: 806 Days
• Field of Search: 623/16.11, 623/20.36, 623/23.32, 623/23.34, 623/23.44, 623/23.51
• US Class Current: 623/23.34
• CPC Class Codes: A61F 2/3094 Designing or manufacturing processes
• CPC Class Codes: A61F 2/30942 for designing or making customized prostheses, e.g. using templates, CT or NMR scans, finite-element analysis or CAD-CAM techniques
• CPC Class Codes: A61F 2/30965 Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping
• CPC Class Codes: A61F 2/36 Femoral heads ; Femoral endoprostheses
• CPC Class Codes: A61F 2/3662 Femoral shafts
• CPC Class Codes: A61F 2002/30009 differing in fibre orientations
• CPC Class Codes: A61F 2002/30014 differing in elasticity, stiffness or compressibility
• CPC Class Codes: A61F 2002/30065 thermoplastic, i.e. softening or fusing when heated, and hardening and becoming rigid again when cooled
• CPC Class Codes: A61F 2002/30084 Materials having a crystalline structure
• CPC Class Codes: A61F 2002/30955 using finite-element analysis
• CPC Class Codes: A61F 2002/30957 using a positive or a negative model, e.g. moulds
• CPC Class Codes: A61F 2002/30971 Laminates, i.e. layered products
• CPC Class Codes: A61F 2002/3625 Necks
• CPC Class Codes: A61F 2210/0071 thermoplastic
• CPC Class Codes: A61F 2250/0018 differing in elasticity, stiffness or compressibility
• CPC Class Codes: A61F 2250/0028 differing in fibre orientations
• CPC Class Codes: A61F 2310/00173 Graphite

Abstract

The present invention discloses a side-dependent prosthetic device. The side-dependent prosthetic device is a composite prosthetic device with a longitudinal direction. The composite prosthetic device includes a plurality of plies wherein each ply being composed of a plurality of reinforced fibers aligned in a ply orientational angle θi relative to the longitudinal direction of the prosthetic device, where i=1,2,3, . . . ,N and N being the number of the plies. The plurality of plies are laminated together for forming the prosthetic device wherein the ply orientational angles being arranged such that θ1+θ2+θ3+ . . . +θ_N−0 thus forming an unbalanced composite prosthetic device. In another preferred embodiment, the ply orientational angles θi forming a sequence which is represented by ((θ¹/θ²)_s)_n where a first ply with orientational angle θ¹ being followed by a second ply with orientational angle θ² wherein such a sequence repeated n-times and arranged to be symmetrical to a mid-plane, wherein θ¹ being an angle close to −10_i and θ² being an angle close to −20_i.

Claims

1. A composite prosthetic device provided for implanting in a femoral bone having a shaft and a neck, wherein said shaft oriented in a longitudinal stem-length direction defining a longitudinal axis and said neck extended from said shaft at a positive acute angle θ

_NECK relative to said longitudinal axis, said prosthetic device comprising;

a plurality of plies wherein each ply being composed of a plurality of reinforcing fibers aligned in a ply orientational angle θ

i relative to said longitudinal axis where i=1, 2, 3, . . . ,N and N being the number of said plies;

said plurality of plies being laminated together for forming said prosthetic device wherein said ply orientational angles represented θ

1, θ

2, θ

3, . . . , and θ

_N, are negative acute angles with respect to said longitudinal axis wherein θ

1+θ

2,+θ

3+ . . . +θ

_N, is a none-zero negative value thus forming an unbalanced prosthetic device.

2. The composite prosthetic device of claim 1 wherein:

said ply orientational angles θ

i, where i=1,2,3, . . . ,N, forming a sequence represented by ((θ

¹/θ

²)_s)_n where a first ply with orientational angle θ

¹ being followed by a second ply with orientational angle θ

² with such a sequence repeated n-times and arranged to be symmetrical to a mid-plane at about half-way between the two ply orientations wherein said θ

¹ being an angle close to −

10° and

θ

² being an angle close to −

20°

relative to said longitudinal axis wherein n(θ

¹+θ

²) is a none-zero negative value thus forming an unbalanced prosthetic device.

3. The composite prosthetic device of claim 2 wherein:

said plurality of reinforced fibers being embedded in a matrix of biocompatible polymeric material.

4. The composite prosthetic device of claim 1 wherein:

said plurality of plies composed of reinforcing fibers are bend plates composed of a plurality of bend reinforcing fibers aligned in a ply orientational angle θ

i relative to said longitudinal axis running along said stem length of said prosthetic device, where i=1, 2, 3, . . . ,N and N being the number of said plies and said θ

1+θ

2,+θ

3+ . . . +θ

_N, is a none-zero negative value thus forming an unbalanced prosthetic device.

5. The composite prosthetic device of claim 1 wherein:

said plurality of plies composed of reinforcing fibers are flat plates composed of a plurality of flat reinforcing fibers aligned in a ply orientational angle θ

i relative to said longitudinal axis running along said stem length of said prosthetic device, where i=1, 2, 3, . . . ,N and N being the number of said plies and said θ

1+θ

2,+θ

3+ . . . +θ

_N, is a none-zero negative value thus forming an unbalanced prosthetic device.