Statistical Validation of the Grand Rapids Arch Collapse Classification

BACKGROUND: The Grand Rapids Arch Collapse Classification system was devised in 2011 to assist physicians’ and patients’ understanding of the mechanisms underlying arch collapse. Five types of arch collapse are described, based on which part of the foot or ankle is affected. The purpose of this study was to determine the inter- and intrarater reliability of this classification system when used by physicians with various levels of training. METHODS: A senior author identified a stratified selection of 50 patients (10 per classification type) who presented with foot/ankle pain and suitable radiographs. A survey was designed using prediagnosis radiographs and clinical synopses of the patient’s chart. The survey consisted of a description of the classification scheme and the 50 cases in a randomized order. Eight weeks later, they repeated the test to analyze for intra-rater agreement. RESULTS: Of the 33 physicians who received the survey, 26 completed the first round (16 attendings, 4 foot and ankle fellows, and 6 residents). Overall, there was substantial agreement among raters in all five types. Kappa scores for each type were 0.72, 0.65, 0.72, 0.70, 0.63, respectively. The combined kappa score was 0.68. After 8 weeks, 13 of the 26 participants repeated the study. A Kappa analysis was once again performed for the 13 respondents, which produced a substantial level of agreement with a value of 0.74 for intrarater reliability. CONCLUSION: The Grand Rapids Arch Collapse Classification system was designed to provide an accessible mechanism for physicians to consistently describe arch collapse, its effects, and the conditions associated with it. The utility of this system is wholly reliant on the repeatability among clinicians. This study has demonstrated that the classification system has substantial rates of reliability among physicians of different levels of experience and training. LEVEL OF EVIDENCE: Level IV.