Fig. 1 above; Fig 2 below

DRAFT

Session on ITA Medical Panel

Creating Value for Medical Products through Titanium Powder Metal Technology

By Stanley Abkowitz, Susan M. Abkowitz

Dynamet Technology, Inc.

Titanium and its alloys are the material of choice for medical devices due to their inherent properties such as strength, lightweight, durability, biocompatibility and osseointergration. Powder metal manufacturing technology provides a new opportunity to custom engineer novel titanium compositions and structures with new and useful combinations of properties, not producible by traditional melt processing. This approach provides the opportunity for new materials-based solutions to the medical device designer to overcome the limitations of current material options in the design and manufacture of higher performing medical device products.

In the early 1950’s, when titanium found its way into military

applications, there were reports of “superiority of titanium over vitallium and stainless steels and that bone will grow in contact with titanium and is fully well tolerated within the system.” Bone plates and screws, when implanted in animals for several months, showed the deposition of bone in threads of the screws and holes of the plates. Figure 1 shows an x-ray of a simple implanted fracture with titanium implant. It is taken from my 1955 book, “Titanium In Industry” crediting the Rem-Cru Review, a publication of one of the first titanium mill product producers.

By 1968 Prof. Joel Hirshhorn of University of Wisconsin received

samples of PM porous titanium bars from a Dynamet Technology (in formation) and reported that the metal implants allowed “living tissue to grow into the porosity. This tissue in-growth results in better bonding between the implant and the surrounding tissue.” The public disclosure of this research was first announced in Product Engineering Magazine, published November 18, 1968. See Figure 2.

By the late 1970’s, titanium alloy total knee and hip replacements

were quickly becoming routine. Currently in the U.S., over 600,000 hip and a similar amount of knee replacements are routine and increasing. These employ porous titanium cladding for tissue ingrowth. Most use Ti-6Al-4V as the titanium alloy of choice.

Now with its latest advances in powder metal technology, Dynamet

has developed novel titanium compositions with significantly improved properties to expand the use of titanium in medical devices and for other applications. This is enabled by the lower sintering temperature (vs. melting) employed to produce the product. Dynamet is working with a major orthopedic company in the development an advanced femoral (knee) component where Dynamet’s innovative titanium alloy offers enhanced performance including wear resistance.

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(Fig. 3)

(Fig. 2)

Dynamet’s PM titanium metal matrix composite (MMC) reinforced with ceramic particulates.

CermeTi® MMC is now being used by Medtronic for an artificial cervical disc, eliminating the use of stainless steel. Steel is less desirable due to its poor imaging characteristics, causing distortion in the MRI or CT scans. The MMC material that possesses the excellent biocompatibility and imaging characteristics of titanium coupled with the wear resistance of steel, is now used in the manufacture of Medtronic’s Prestige LP articulating disc replacement shown in Figure 3. This provides an excellent example of a successful orthopedic device resulting from the combined expertise of a leading medical device manufacturer and a developer and manufacturer of innovative titanium materials.

The Medtronic Prestige-LP disc implant is in commercial use outside the United States and is

undergoing clinical trials in the US. An animation describing this disc can be found at http://www.prestige.com/intl/about-prestige-disc.html

Figure 3 Ref: Published in Advance Materials and Processes Magazine

Follow with video http://www.prestigedisc.com/intl/playvideo.html?filename=prestige56