The Importance of Cleaning Modular Parts on Visual Scores of Taper Damage

摘要

There have been increasing reports of wear and corrosion of modular junctions between the femoral balls and stems. The assessment of modular component corrosion has been largely based on the subjective, visual inspection of explanted modular interfaces. In this study, 51 modular specimens from a variety of total hip explants were given visual corrosion scores by three observers, first after a light rinsing (R1) and then again after a thorough soaking and scrubbing (R2), to determine the influence of cleaning on visual scoring methods. Each observer scored the specimens three separate times, and each time, two different scoring methods were used: the four-point Goldberg method (G) and the five-point Fricka method (F). After thoroughly cleaning the specimens, the intraobserver reliability of both methods increased (6: R1-0.62, R2-0.70; F: R1-0.50, R2-0.64). Although the interobserver reliability for the Goldberg method was unchanged (R1-0.54, R2-0.55), the interobserver reliability of the Fricka method substantially decreased (R1-0.41, R2-0.15), suggesting that cleaning lowered the consistency in methodology for this scoring method. Additionally, the reliability between the first and second round was found to be higher for the Goldberg method than for the Fricka method (G-0.62, F-0.47). Differences between first-round and second-round scores ranged from 0 to 2 points. Both methods emphasize the dark discoloration, although some may be artifactual; therefore, cleaning is recommended to remove any debris and to expose surface features. In the absence of deposits and evidence of fretting, it was hard to assign an appropriate score in cases in which the predominant feature was surface grooving, which was not included in the criteria for either method. Visual corrosion scoring would be improved if the score accounted for the formation of grooves that are a common feature of many explanted tapers.