Year 2021
September 2021


Abstract Title
A proposed Clinical and Functional Classification System for Posterior Tibial Tendon Dysfunction to better aid its prognostication and treatment decisions



Tan Tock Seng Hospital1

Background & Hypothesis

There are various classification systems for staging Posterior Tibial Tendon Dysfunction (PTTD). The Johnson and Strom Classification (JSC), remains widely used among practitioners, and is commonly cited in research on PTTD. JSC provides a broad classification system. However, it does not take into account case-specific variables for determining conservative treatment plan. We aim to develop a classification system that is guided by clinical and functional assessments to accurately stage PTTD and guide conservative management.


The authors formulated a new classification system derived from JSC. It consists of an expanded Stage 0, 1, 2, 2+, 3 and 4. The proposed classification was tested against JSC for level of concordance using Fleiss’ Kappa amongst eight podiatrists practising in a tertiary hospital setting. These raters were from varied training background and had different levels of experience. Raters were asked to stage 10 PTTD cases consecutively using the JSC system before staging the same cases using the proposed new classification.


There was a Moderate inter-rater agreement when JSC was used, K = 0.513 (P<0.001), 95% CI: 0.442-0.584. With the new proposed classification, there was a Substantial agreement amongst raters, K = 0.769 (P<0.001), 95% CI: 0.709–0.829.

Discussion & Conclusion

Our proposed classification shows better agreement amongst practicing podiatrists when compared to the widely used JSC. This provides preliminary evidence to support its use in clinical practice through a more comprehensive stratification of PTTD cases. This may possibly lead to better prognostication and treatment decisions. The proposed new classification can potentially be used for future research on PTTD.