Computer-assisted radiographic wear measurement

All of the in vivo wear measurement techniques described in this section related to TKA have certain drawbacks and unique limitations. Certainly all of these methods are predicated on the presence of a metallic tibial baseplate. In this respect, radiographic wear assessment in the hip and the knee share a common limitation, although the inclusion of a radiographic wire marker in all-UHMWPE cups has somewhat alleviated this concern. In addition, from a practical perspective, both fluoroscope-assisted or computer-assisted radiographic techniques for TKA are more cumbersome and nonstandard than the methods used to obtain radiographs for routine clinical diagnosis. Ultrasound as a wear measurement technique for TKA is in its infancy, insofar as widespread acceptance is concerned. Finally, the absolute accuracy of these in vivo wear... 

In contrast, a two-dimensional computer-assisted technique using edge detection and computer vision, developed by Martell and Berdia, improves intraobserver and interobserver repeatability tenfold over manual techniques (Martell and Berdia 1997). Figure 5.10 illustrates the Martell technique for computer-assisted measurement of radiographic wear. 

Wear can be measured from radiographs using manual or computer-assisted techniques. The Chamley method. 

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