Orthopaedic Production Solutions
R&D Solutions for Orthopaedics
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Artificial Hip Joint Profiler
The Artificial Hip Joint Profiler is a fast, non-contact three dimensional measuring instrument that checks component form in a matter of seconds or minutes with a resolution as low as 3 nm.
It is the result of nearly 15 years' experience in precision non-contact form metrology and provides unparalleled levels of 3D data capture for radius, sphericity and wear in the measurement of artificial hip joints.
The use of proven optical sensors leads to a significant increase in measurement speed without damaging the bearing surface, this making the instrument suitable for 100% inspection in volume production. |
In brief: -
Combines the advantages of a roundness instrument and a CMM with the speed of an optical technique. -
Provides fast, high resolution information on the whole bearing surface of an artificial hip joint. -
Typical measurement times are under two minutes, making the instrument suitable for R&D as well as quality control in volume production. -
Measures heads as well as cups with a resolution as low as 3 nm. -
Can measure materials such as ceramics, metals, polyethylene, PEEK and many others. -
Easy instrument control via familiar Windows user interface. -
Data analysis, automation and export of results for fast report generation come as standard.
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| 3D Data sets produced on the Artificial Hip Profiler.
|  |  | | Ceramic Head A sphere fit gives the radius of the ceramic head
as 17.979 mm. The colour represents the
deviation from the ideal spherical form – in the case above +1.254 μm and -2.302 μm at the highest and lowest points respectively. | Ceramic Cup
The quantities of interest on a cup are the radius, deviation from spherical form and the internal depth. This cup has a radius of 18.073 mm giving a clearance between head and cup of 94 μm
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The instrument control for the Artificial Hip Profiler runs from the standard Windows interface enabling the operator to control the instrument with ease. Data analysis and fast report generation are standard with the RedLux software. A sample report is shown below:
RedLux AHP
Name: Operator1
Works-Order#: WO-123456
Part#: 987-654
Cast ID: 022
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Date: 10 July 2011
Time: 10:06:21
Cup Radius:
NV 18.080 mm AV: 18.073 mm
UT 0.010 mm DV: -0.007 mm
LT -0.010 mm PASS
Internal Depth:
NV 18.010 mm AV: 18.014 mm
UT 0.015 mm DV: 0.004 mm
LT 0.015 mm PASS
It is also possible for the end user of the machine to program the instrument to perform custom measurement and analysis, making a seamless integration into existing production management systems a reality.
R&D Solutions for Orthopaedics
Artificial Hip Joints – Retrieval Analysis
Retrieval analysis is an important tool for gaining an understanding of failure mechanisms in artificial hip joints. The RedLux profiler makes this crucial task easier and faster while at the same time providing more meaningful information and lowering the cost of analysis.
Retrieval Analysis until Now
Commonly, coordinate measuring machines (CMM) and roundness instruments are used to evaluate wear on artificial hip joints, but both have their disadvantages. The CMM will only measure a few data points and the resolution is generally not sufficient to measure small wear volumes. A roundness instrument has a higher resolution but will only measure the joint in 2D traces that have to be interpreted by a skilled operator. Both methods can take hours, with much trial and error to find the deepest point of a wear scar.
Retrieval Analysis in Future
The RedLux Artificial Hip Profiler combines the higher resolution of a roundness instrument with the coverage of a CMM and the speed of an optical technique to provide fast, high-resolution information on the whole component. Typical measurement times range from seconds to just a few minutes, making the instrument suitable for instant analysis of retrievals.
The images below show 3D data sets of a failed resurfacing device, retrieved after 3.5 years. |
Head – 901,800 data points
A sphere fit to the unworn surface gives the original radius as 18.928 mm. The colour represents the deviation from ideal spherical form with pink indicating the unworn surface and the various colours from red over yellow, green, blue to purple express the depth of the wear scar. The deepest point on the head is instantly visible and can be quantified as 52.5 μm. |
Cup – 685,800 data points
The matching cup has an original radius of 19.032 mm, giving a clearance between head and cup of 104 μm. This cup exhibits edge wear of 529 μm at the deepest point. | Specifications
The RedLux profiler can measure most materials, including metal, ceramic and polyethylene. With resolutions as low as 3 nm, even the lowest wear on metal or ceramic components can be analysed as demonstrated below.
Comparison CMM, Roundness, RedLux
In contrast to other methods, the RedLux profiler offers fast and easy analysis of retrievals. It can measure the radii of head and cup in 3D, the deviation from a sphere and all at a resolution comparable to that of a roundness instrument. |
The RedLux profiler is the only instrument that can measure low volumetric wear of hard-on-hard bearings fast and accurately.
The familiar Windows® user interface lets the operator control the instrument with ease. Data analysis, automation and export of results for fast report generation come as standard. | | | | |
