Natural Polymer-Based Porous Orthopedic Fixation Screw for Bone Repair and Regeneration

• US 20170303980A1
• Filed: 07/13/2017
• Published: 10/26/2017
• Est. Priority Date: 02/23/2010
• Status: Abandoned Application

• Current Assignee: University of Connecticut (State of Connecticut)
• Original Assignee: University of Connecticut (State of Connecticut)
• Inventors: Kumbar, Sangamesh G., Laurencin, Cato T.
• Application Number:
  US15/649,044
• Publication Number:
  US 20170303980A1
• Time in Patent Office: Days
• CPC Class Codes: A61B 17/866 Material or manufacture
• CPC Class Codes: A61B 2017/00004 (bio)absorbable, (bio)resorbable, resorptive for implantable prostheses A61F2210/0004
• CPC Class Codes: A61B 2017/00526 Methods of manufacturing
• CPC Class Codes: A61L 31/042 Polysaccharides
• CPC Class Codes: A61L 31/125 having a macromolecular matrix
• CPC Class Codes: B29C 39/02 for making articles of definite length, i.e. discrete articles
• CPC Class Codes: B29C 39/38 Heating or cooling
• CPC Class Codes: B29C 67/04 Sintering combined with compression B29C43/00
• CPC Class Codes: B29C 67/24 characterised by the choice of material
• CPC Class Codes: B29K 2001/08 Cellulose derivatives
• CPC Class Codes: B29K 2001/12 Cellulose acetate
• CPC Class Codes: B29K 2005/00 Use of polysaccharides or derivatives as moulding material
• CPC Class Codes: B29K 2105/251 Particles, powder or granules expandable particles B29K2105/046
• CPC Class Codes: B29L 2031/7546 Surgical equipment

Abstract

A bone fixation device made of polysaccharide particles or microspheres fused into a solid structure is provided herein. The bone fixation device may be in the form of an orthopedic screw, orthopedic pin, or orthopedic plate. Methods of making the bone fixation devices described herein are provided as are methods of treating patients in need of bone repair or replacement by implanting a bone fixation device described herein in the patient at a site of bone damage, ligament damage, or bone deformity.

Claims

1. A bone fixation device comprising:

a cellulose acetate-hydroxyl apatite composite, wherein the composite comprises 15% hydroxyl apatite and wherein the cellulose acetate has a molecular weight of 30,000 Da or 50,000 Da, wherein the composite is comprised of fused microspheres having a diameter of between 50 um and 400 um.

2. The bone fixation device of claim 1, wherein the composite comprises a porosity of between 33% and 37%.

3. The bone fixation device of claim 1, wherein the composite comprises pore diameters of between 120 urn and 150 um.

4. The bone fixation device of claim 1, wherein the bone fixation device is a cylindrical screw or an interference screw.

5. The bone fixation device of claim 1, wherein the cellulose acetate has a molecular weight of 50,000 Da.

6. A method of making a bone fixation device comprising providing a plurality of polysaccharide microspheres or polysaccharide particles in a mold, wherein the mold is in the form of the bone fixation device;

providing a solvent system having an organic solvent fraction and an aqueous fraction dropwise in the mold;

removing excess solvent from the mold; and

drying the microspheres or particles in the mold.

7. A method of treating a patient in need of bone repair, comprising implanting a bone fixation device in the patient at a site of bone damage, ligament damage, or bone deformity, wherein the device consists of a cellulose acetate-hydroxyl apatite composite, wherein the composite comprises 15% hydroxyl apatite and wherein the cellulose acetate has a molecular weight of at least 30,000 Da.