- CORA ABSTRACT #II - 6
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- COMPARISON OF WEAR ANALYSIS TECHNIQUES USING A 3D PHANTOM MODEL
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- W.T. Gofton
- A.J. Hui
- X. Yuan
- S.J. MacDonald
- R.W. McCalden,
- C.H. Rorabeck
- R.B. Bourne
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- Purpose: To compare the accuracy of three methods, Umeå Roentgen stereophotogrammetric analysis (UmRSA), Polyware® (computer software analysis), and a two-dimensional manual caliper technique, in evaluating polyethylene wear using a three-dimensional phantom.
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- Conclusion: Using this in-vitro model, UmRSA was significantly better at identifying polyethylene wear than both Polyware® and a manual caliper technique.
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- Significance: Improving bearing surfaces will require increasingly more sensitive and accurate methods to identify early wear in both the research and clinical setting. This study aids in validating analysis techniques, and to our knowledge is the first use of UmRSA for polyethylene wear analysis.
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- Summary of Methods, Results and Discussion: A 3D total hip phantom, with a validated accuracy (2 mm), was used to compare the three techniques. X-rays in the AP, lateral and RSA planes were analyzed by blinded observers following known movements (range 0.15 to 1.73 mm) of the phantom that simulated polyethylene wear.
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- Three-dimensional UmRSA was highly correlated (r2=0.96) and in almost perfect agreement to the phantom. Three-dimensional Polyware® was also strongly correlated to the phantom (r2=0.88), but underestimated wear in the higher ranges. The manual caliper technique showed the poorest correlation (r2=0.69) tending to overestimate wear. The mean difference between the phantom and UmRSA (0.08 ± 0.08 mm) was significantly smaller (p < 0.05) than both Polywareâ (0.17 ± 0.14 mm) and the caliper technique (0.31 ± 0.20 mm).
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