Custom ceramic bones aid accident recovery

Strong implants can be made to fit from the X-ray scans directly and the surgeon only needs to open up the fracture area for a very short time to insert a well-fitting implant.

Road accidents can leave people with complex fractures that traditionally require implants, pins, traction and a considerable amount of surgical skill to treat.

Often the bone ends at the fracture have lost their blood supply and simply do not knit together.

Bone grafts are one way of improving this situation, but this means the patient has to recover from two invasive procedures.

In recent years there has been a gradual adoption of implants made from "artificial bone", which is usually based on a ceramic called hydroxyapatite.

These implants are generally porous ceramic pieces which can be fashioned to fit the fracture site by the surgeon during an operation.

In 2006 a group of UK businesses and universities came together to work on a new way of making "bespoke" ceramic implants quickly.

The eventual procedure will be for the patient in the emergency department to undergo a scan.

The data from the scan will then be converted into a computer model of the implant needed which is then split into layers.

This computer file is used to drive a special machine which builds the implant layer by layer.

This is done by "writing" (jetting) a thin stream of ceramic ink, with the writing head computer-controlled.

This is not a new technique and has been used to make prototype ceramic components but the inks have traditionally relied on plastic binders to hold the ceramic particles together.

To give the ceramic good strength it is necessary to sinter the ceramic particles together in a furnace.

Once the plastic binders burn out, the ceramic implant shrinks considerably, making it difficult to achieve the right shape.

In the new system a high ceramic solids ink is formulated to set strongly when it is frozen (a process known as freeze casting) and does not have any plastic binders to burn out.

This means that strong implants can be made to fit from the X-ray scans directly and the surgeon only needs to open up the fracture area for a very short time to insert a well-fitting implant.

Other advantages of this methodology are that there are no biocompatibility problems and also porosity can be engineered into the parts to enable blood vessels to grow within the artificial bone.

The Consortium is part funded by a TSB award and are close to building the first prototype machine.

In an age of increasing post-surgical infection problems this procedure offers many advantages.

The consortium is led by Unimatic and other consortium members are Horizon Ceramics , Eurodyne , Ceramisys and ATD Inkjet Systems, as well as De Montfort and Sheffield Universities.

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