CORRInsights®: Current Pathologic Scoring Systems for Metal-on-metal THA Revisions are not Reproducible
Recognizing that tissues around damaged implants show a spectrum of changes, and that any given arthroplasty may show features reflecting more than one mechanism of failure, several groups of researchers have developed grading systems for individual observations [2, 3, 5-7], or combinations of features [1, 4], to semiquantitatively grade the extent to which the morphologic findings in tissue might reflect an adaptive immune response versus infection, mechanical factors, or an innate inflammatory reaction to debris.
In the current study by Smeekes and colleagues, three pathologists tested the reproducibility of two commonly used scoring systems [1, 4], the aseptic lymphocyte vasculitis-associated lesion (ALVAL) score and the modified Oxford ALVAL score. The results provide documentation of what many pathologists have maintained for years: These two scoring systems lack the level of reproducibility that most physicians expect from a routine laboratory test. That does not mean the scoring systems are of no value, but it does illustrate that semiquantitative grading of this type can be difficult and we have room for improvement.