Catania flatfoot score: A diagnostic-therapeutic evaluation tool in children.

Background: Flexible flatfoot (FFF) is a very common condition in children, but no evidence-based guidelines or assessment tools exist. Yet, surgical indication is left to the surgeon's experience and preferences.

Aim: To develop a functional clinical score for FFF [Catania flatfoot (CTF) score] and a measure of internal consistency; to evaluate inter-observer and intra-observer reliability of the CTF Score; to provide a strong tool for proper FFF surgical indication.

Methods: CTF is a medically compiled score of four main domains for a total of twelve items: Patient features, Pain, Clinical Parameters, and Functionality. Each item refers to a specific rate. Five experienced observers answered 10 case reports according to the CTF. To assess inter- and intra-observer reliability of the CTF score, the intra-class correlation coefficients' (ICCs) statistics test was performed, as well as to gauge the correlation between the CTF score and the surgical or conservative treatment indication. Values of 75% were chosen as the score cut-off for surgical indication. Sensitivity, specificity, positive likelihood ratio (PLHR), negative likelihood ratio (NLHR), positive predictive value (PPV), and negative predictive value (NPV).

Results: Overall interobserver reliability ICC was 0.87 [95% confidence interval (CI): 0.846-0.892; P < 0.001]. Overall intra-observer reliability ICC was 0.883 (95%CI: 0.854-0.909; P < 0.001). A direct correlation between the CTF score and surgical treatment indication [Pearson correlation coefficient = 0.94 (P < 0.001)] was found. According to the 75% cut-off, the sensitivity was 100% (95%CI: 83.43%-100%), specificity was 85.71% (95%CI: 75.29%-92.93%), PLHR was 7 (95%CI: 3.94-12.43), NLHR was 0 (95%CI: 0-0), PPV was 75% (95%CI: 62.83%-84.19%) and NPV was 100% (95%CI: 100%-100%).

Conclusion: CTF represents a useful tool for orthopedic surgeons in the FFF evaluation. The CTF score is a quality questionnaire to reproduce suitable clinical research, survey studies, and clinical practice. Moreover, the 75% cut-off is an important threshold for surgical indication and helps in the decision-making process.