PAPER 070: RETRIEVED UHMWPE WEAR ANALYSIS – A COMPARISON OF DIFFERENT METHODOLOGIES

Abstract

Purpose: Implant retrieval analysis provides valuable information to researchers, clinicians and manufactures about the in vivo wear characteristics. Wear analysis can quantify visible damage on retrieved UHMWPE bearing surfaces used in total knee arthroplasty (TKA). Various researchers have developed wear scores to help provide insight into the modes of prosthetic failure. Four scoring methods are compared in order to determine their inter-rater reliability.

Method: A cohort of 60 retrieved G2, Smith & Nephew/Richards, TKA implants were analyzed by two observers using four scoring techniques. The scoring methods used had been developed by Hood, Wasielewski, Currier, and Brandt. The intraclass correlation coefficient (ICC) was used in assessing the inter-rater reliability.

Results: The ICC demonstrated significant correlation between raters (P< 0.05). Hood’s method produced a correlation of 0.89, Wasielewski’s method 0.83, Currier’s method 0.58, and Brandt’s method 0.82. All but Currier’s method had excellent correlation between raters.

Conclusion: The analysis techniques for articular surface wear for total knee bearings by Hood, Brandt, and Wasielewski showed excellent inter rater reliability; however currier’s method was only fair. One common issue among all these methods is that the scoring systems do not identify or assign differentiating weights to clinically relevant wear modalities to capture inferior implants designs. A new wear analysis technique that is efficient and assigns clinical severity weights to wear modes in TKA bearings should be investigated.