CeramTec Medical Products The Fourth Generation of Ceramics Scientific Information and Performance Data

Osteolysis Although total hip arthroplasty is one of the most successful of all surgical procedures, a number of open questions relating to implant design and materials remain. According to the Swedish Register (2012), osteolysis and aseptic loosening are responsible for 68.2   percent of all revisions. The bearing materials used and the volume, size, and biological effects of wear particles play a decisive role in the development of these conditions. The second most frequent complication is dislocation created by prosthetic impingement and insufficient joint stability. Instability Component...

Synovial Fluid Lubrication There remains a limited understanding of the actual processes governing the tribological performance of artificial joints. Unlike natural cartilage, even modern material combinations do not allow for a permanent lubrication film to separate the two surfaces. For that reason wear-resistant materials with optimal surface characteristics play a key role in determining the tribological outcome of arthroplasty. Taper Corrosion Corrosion at the head-neck taper has recently been found to be an important factor for the outcomes of THA, and its severity is multi-factorial. There...

Proven High Performance Ceramics BIOLOX®delta More than 40 years of experience in ceramic hip replacements together with more than 10 million BIOLOX® implanted components confirms CeramTec as a world leader in this technology. Surgeons all over the world put their faith in CeramTec’s pink-colored BIOLOX® delta ceramic. This colour gives surgeons the certainty that they are using implants of the highest quality and reliability for their patients – from CeramTec. BIOLOX® delta is the only ceramic with 10 years of successful clinical experience. About 95 percent of all ceramic implants for hip arthroplasty...

Proven High Performance Ceramics Extreme Hardness The purest raw materials and a manufacturing process that has been refined over decades ensure the highest degree of material uniformity, mechanical properties and perhaps most importantly, hardness. This results in excellent wear resistance. Exacting Sphericity The femoral ball heads have a maximum variance from the ideal sphere of only 5 micrometers, whilst the inserts have a maximum variance of 7 micrometers. This ensures that the articulation design produces the least amount of wear possible (testing accurancy <1 micrometer). Optimal Clearance...

Text: CeraNews 2/2010 – Usbeck

Superiority in Extreme Conditions Foreign particles that are harder than the bearing surface lead to high levels of wear (left). Surfaces made of high performance ceramics remain largely unchanged (right). Source: CeramTec GmbH Source: CeramTec GmbH Source: CeramTec GmbH Source: CeramTec GmbH Scratched surfaces increase abrasion in cup liners made of PE, XPE and metal (left). Only an unscratched, smooth surface of the sort achieved in BIOLOX® ceramics enables optimal wetting, outstanding lubrication and minimal wear (right). Hydrogen bonds with ceramic surfaces ensure excellent wettability and...

Molecular Bonding Loose Metal Structure The molecular structures of metal alloys and ceramic materials are fundamentally different. In the case of a metal bond, the electrons orbit the atomic nuclei in an irregular manner and with relatively low bonding strength. As a result of this, metal ions continuously exit this molecular structure and are absorbed by the surrounding tissues. This occurrence can result in many different chemical and biological reactions. Stable Ceramic Structure In ceramic molecules, the electrons follow exact orbital paths. The electrons’ bonding strength is very high,...

Hardness and Toughness Combined The extremely stable ceramic bond virtually rules out any possibility of plastic deformation. While this permits the desired degree of extreme hardness, it also leads to a relatively high degree of brittleness. How­ ver, by optimising the ceramic composition e one can achieve both extreme hardness and strength. Such composite models exist in nature and in modern technology. Damascene steel combines hard and ductile alloys to form a highly firm and resistant material. Source: stienenDamast, Mönchengladbach, Germany Source: J.D. Verhoeven, A.H. Pendray, W.E. Dauksch,...

The MULTIGEN PLUS Ceramic Knee (Limacorporate, top) The BPK-S Ceramic Knee (Peter Brehm GmbH, middle, bottom) Text: CeraNews 2/2010 – Usbeck

Intelligent Reinforcement Mechanisms A Fundamental Difference Material sciences make a distinction be­ ween fracture strength and fracture tought ness. Fracture strength is the maxi­ um mechanical stress a material can withstand m without fracturing. Fracture toughness is the resistance of a material to the propa­ gation of cracks. Ceramic materials that have been in use for a number of years, such as BIOLOX®forte, already have a very high fracture strength. BIOLOX® delta additionally exhibits an extremely high fracture toughness. It has a much higher capacity than other ceramic materials to...

Optimized Microstructure The microstructure of BIOLOX®delta: platelets with crack-stopping function (1), aluminum-oxide particle (2), zirconium-oxide particle (3). Significantly smaller grain size and higher uniformity (compared to BIOLOX®forte, left) make even smoother surfaces possible and enhance the material properties. 2 µm Source: CeramTec GmbH The principle of conversion reinforcement: zirconium oxide particles act like airbags by absorbing impacting forces (left). Source: CeramTec GmbH Crack propagation The principle of platelet reinforcement: platelet-shaped crystals block the propagation...

Text: CeraNews 2/2010 – Usbeck

Long-lasting Strength Improved Properties The burst strength test assesses ceramic components by exposing them to axial loading until the point of material failure. Ball heads made of BIOLOX® delta (28mm) resist loads of more than 80 kN when tested. Larger ball heads show an even higher burst strength. The burst strength of BIOLOX® delta is considerably higher than that of conventional aluminum oxide ceramics. Furthermore, tests on standard material samples show that the bending strength of BIOLOX® delta is not adversely affected by repeated autoclaving. While hydrothermal instability can occur...