Orthopaedics

High Precision, Non-Contact, Data-Rich Metrology for Orthopaedic Production

Advanced data reporting is critical for analysing and providing the information for design and quality control in the production process, or to understand in-situ behaviours of components. Medical Orthopaedics must comply with rigorous standards and regulation. This is to ensure full control over the manufacturing processes is achieved at all times. Stringent medical tolerances, highly complex forms and finishes on a challenging array of materials, means that the technology required for accurate analysis of components must also push the limits and stay at the cutting-edge of production methods. Patient quality of life depends on it.

Artificial Head & Cup

The contactless OrthoLux generates data-rich 3-dimensional images and gives on-screen results for analysis as soon as the measurement of artificial implant components is completed. For example the deviation from design intent of an artificial hip head component can be seen instantly as shown in the image. OrthoLux analyses the entire surface of the sphere with highest precision and can provide our customers with data-rich reports that are needed for design and quality control.

The image on the left shows a head with colour showing deviation from perfect sphere. In this example, blue and purple depict the greatest deviation from reference, with a peak-to-peak value of 5 µm. Additionally the radius is measured at 15.993 mm.


These measurements will take between 20 and 100 seconds to execute and the data is available instantly.


The reports can be shown as fully illustrated residual error maps or GD&T (geometric dimensioning and tolerancing) type measurement or in table format according to individually set CTQ parameters.

Corresponding measurements can be taken of the cup, the image on the right showing the deviation from perfect form, with a peak-to-peak value of 8 µm. Here the radius is 20.058 mm.

The hip cup rim plays an important part during the manufacturing process, since the last few millimetres of contact loading between the head and cup edge can have a significant impact on how long a hip joint lasts. The process of finishing the rim of a cup during manufacturing is separate from the creation of the main bearing surface. This often leads to an axial misalignment or continuity disconnect between these two important features of the joint. Although the cup rim is generally very well specified, it is a difficult feature to control in manufacturing and verifying the profile is very difficult and has been impractical. OrthoLux has the ability to speedily analyse the artificial hip cup including the rim with highest precision, providing data-rich information on geometry and possible deviation from design intent.


The evaluation of quality and performance is of highest importance throughout the life-cycle of an implant component, and the assessment of reliability and product life of retrieved components is an important tool for gaining valuable information.
The contactless CMM OrthoLux speedily provides data-rich reports meeting the requirements of research institutes.

The images show 3D data sets of an artificial hip joint, retrieved after 3.5 years. 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.

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.

Sub-nanometre roughness and surface texture measurement can be achieved with the optional White Light Interferometer head.

Artificial Head and Stem Tapers

RedLux non-contact metrology technology and equipment is fast, accurate and data-rich and is able to offer measurement and analysis of artificial head and stem tapers, enhancing the analysis of a complete retrieved joint. This provides valuable and traceable information on head and stem taper wear, which is imperative to the analysis and the understanding of component behaviour.

Measurement times are in the order of 10-15 minutes providing very high-density data sets with nanometre resolution, typically between one and two million data points. This allows the measurement and analysis of taper form and surface roughness - of a large number of components - within a short period of time.

Internal Tapers

Our non-contact metrology technology and equipment is enables the is fast, accurate and data-rich inspection of internal tapers and therefore provides the anwer to ever increasing demands for taper quality control. Currently, manufacturers have to employ several machines to ascertain features such as taper angle, defined diameters, depth, roundness, straightness and surface finish.
 

The RedLux metrology system captures these features seamlessly, making it the state-of-the-art metrology solution for the inspection of internal tapers.    

The image to the left shows the data image of the internal taper of an artificial hip joint as well as a detailed report with Pass/Fail indicator.
 

Orthopaedics R&D

The evaluation of quality and performance never stops, and the ability to rapidly assess the reliability and product life of retrieved components, means RedLux’s non-contact systems are used all over the world for this purpose.

Our non-contact metrology technology and equipment is fast, accurate and data-rich, designed especially to meet the specific requirements of this exacting industry. Components that are delicate and complex can be accurately measured with unrivalled speed, and because our non-contact white light technology and customised software is so advanced, we can provide a rich array of data giving invaluable insight into component behaviour. Providing data-rich, traceable information at highest precision when it’s needed most.

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