Comparison and agreement of outcome scores through nine months after acetabular fracture fixation

The Modified Merle d'Aubigne-Postel Score and the Harris Hip Score are commonly used to assess the functional outcomes after acetabular fractures. A previous report showed that correlation between scores is good, that there is poor concordance among functional classes, and that the distribution of the scores is highly asymmetrical. Several issues were not addressed in this report, mainly that the data set was treated as transversal data without comparison of scores through time; therefore the objective of this article is to assess the degree of correlation and concordance between the Modified Merle d'Aubigne-Postel Score and the Harris Hip Score during the first 9 months after acetabular fracture treatment.

Both scores were recorded in a cohort of 23 previously healthy patients after 3, 6 and 9 months after fixation of acetabular fractures. Through a mixed-effects repeated measures model, we assessed differences between standardized scores. Pearson's interclass correlation coefficients for full scores and each of their domains, as well as agreement for clinical graduation classification was calculated.

Between score correlation was 89%. We found no differences between scores at 3, 6 and 9 month follow-ups. Agreement between scores was 0.95, while agreement for clinical graduation classification was 0.67.

Very short term correlation and concordance between scores is excellent, while concordance for clinical graduation classification is modest. We suggest the widespread use of the simpler score.