Fracture fixation systems

Abstract

Systems for bone fracture repair are disclosed. One system includes a biocompatible putty that may be packed about a bone fracture to provide full loadbearing capabilities within days. The disclosed putties create an osteoconductive scaffold for bone regeneration and degrade over time to harmless resorbable byproducts. Fixation devices for contacting an endosteal wall of an intramedullary (IM) canal of a fractured bone are also disclosed. One such fixation device includes a woven elongated structure fabricated from resorbable polymer filaments. The woven elongated structure has resilient properties that allow the woven structure to be radially compressed and delivered to the IM canal using an insertion tube. When the insertion tube is removed, the woven structure expands towards its relaxed cross-sectional width to engage the endosteal wall. The woven elongated structure is impregnated with a resorbable polymer resin that cures in situ, or in the IM canal.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority to U.S. Provisional Application Ser. No. 61 / 142,756, filed on Jan. 6, 2009, U.S. Provisional Application Ser. No. 61 / 084,237, filed on Jul. 28, 2008, U.S. Provisional Application Ser. No. 61 / 083,837, filed on Jul. 25, 2008, and G.B. Provisional Application Serial No. 0813659.0, filed on Jul. 25, 2008. The disclosure of each application is incorporated by reference in its entirety.BACKGROUND[0002]1. Technical Field[0003]This disclosure relates generally to orthopedic implants and, more particularly, to orthopedic implants adapted for fracture repair and methods for repairing fractures.[0004]2. Description of the Related Art[0005]A variety of systems and devices are conventionally used to treat bone fractures in humans or animals. Bone fractures typically heal naturally as a result of normal growth or regeneration processes. Treatment of bone fractures generally includes placing bone fragments into an anatom...

AI Technical Summary

Benefits of technology

[0014]The disclosed putties may include a first or primary filler in the form of biocompatible and osteoconductive particles that can form a scaffold structure that bridges healthy bone segments. The first or primary filler, preferably in the form of particles, may also provide porosity, bone ingrowth surfaces and enhanced permeability or pore connectivity. One suitable particulate filler material is hydroxyapatite (HA) although other suitable filler materials will be apparent to those skilled in the art such as calcium phosphates, orthophosphates, monocalcium phosphates, dicalcium phosphates, tricalcium phosphates, whitlockite, tetracalcium phosphates, amorphous calcium phosphates and combinations thereof.

[0017]In a refinement, the porosity and compressive properties of the disclosed putties may be manipulated using additional fillers materials that may be HA or another suitable biocompatible material. Such refinements include the addition of particles having mean diameters ranging from about 400 to about 4000 μm. In certain disclosed putties, the additional filler materials may be provided in one or more size distributions. For example, additional filler material is provided in size distributions ranging from about 400 to about 4200 μm, from about 400 to about 3200 μm, from about 600 to about 3000 μm, from about 800 to about 2800 μm, from about 400 to about 2200 μm, from about 800 to about 1800 μm, from about 1400 to about 3200 μm, from about 1800 to about 2800 μm, etc. The ratio of the particle size distributions can be manipulated depending upon the compression strength required or the porosity required. For example, large segmental defect injuries to load bearing bones will necessitate higher compression strength and possibly reduced porosity. In contrast, large segmental defect injuries to non-load bearing bones require less compression strength thereby enabling the surgeon to use the putty with a higher porosity for shorter healing times.

[0025]Fixation devices for contacting an endosteal wall of an intramedullary (IM) canal of a fractured bone are also disclosed. One such fixation device comprises a woven elongated structure fabricated from a resorbable polymer filaments. The woven elongated structure may have a relaxed cross-sectional width and a compressed cross-sectional width. The relaxed cross-sectional width may be at least about 50% larger than the compressed cross-sectional width. This resilient property allows the woven structure to be radially compressed, placed in an insertion tube and delivered to the IM canal using the insertion tube. When the insertion tube is removed, the woven structure expands towards its relaxed cross-sectional width to engage the endosteal wall. The woven elongated structure may have a closed distal end. The woven elongated structure is coated with a resorbable polymer resin that cures in situ, or in the IM canal. The combination of the woven elongated structure and the cured resin provides a strong internal fixation device.

[0035]The disclosed fixation systems and methods may yield one or more of the following benefits: (1) the patient may be more rapidly restored to ambulatory function while healing naturally occurs; (2) a single procedure may be employed that significantly simplifies orthopedic surgery; (3) fewer secondary fractures may result from use of the disclosed systems and methods thereby promoting normal healing and fewer infections; (4) reduction in recovery / rehabilitation time; (5) potential treatment for severe bone loss; (6) potential treatment for joint fractures; (7) reduction in the number of amputations; (8) the fixation systems are wholly or at least partly resorbable thereby avoiding the need for a secondary procedure to remove the fixation device after the bone has healed.

Problems solved by technology

The disclosed putties may also degrade over time to harmless resorbable by-products as normal bone regenerates.

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