In Haglund syndrome, standard radiologic measurements lack specificity and reliability in assessing etiologic morphologic calcaneal abnormalities. We report a simple X/Y ratio to measure posterior calcaneal length, where X is calcaneal length on lateral weight-bearing view and Y is greater tuberosity length.

To compare this new parameter against the radiologic gold standard in a group of Haglund patients and a healthy control group.

Measuring this ratio significantly distinguishes between Haglund patients and healthy subjects.

A retrospective study included 50 Haglund syndrome patients and 30 healthy controls. Standard measurements (Fowler-Philipangle, Chauveaux-Liet angle, Ruch pitch, Heneghan-Pavlov test) and X/Y ratio were calculated twice by 2 independent observers. Intra- and inter-observer correlations were calculated, as were the specificity and sensitivity of the various parameters, with a ROC curve to establish the X/Y threshold.

All measurements were reproducible on intra- and inter-observer testing. There were no significant inter-group differences in standard measurement specificity or sensitivity. The Haglund group showed significantly lower X/Y ratio (2.07) than controls (2.70; p<0.0001), with a cut-off at 2.5. Threshold sensitivity in confirming Haglund syndrome was 100% (p<0.0001) and specificity 95% (p<0.0001).

This new parameter measures the length of the calcaneus and its greater tuberosity. It is more reliable and reproducible in terms of sensitivity and specificity than standard measurements in Haglund syndrome. The 2.5 ratio threshold can guide surgical decision-making.

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