The Zadek calcaneal osteotomy in Haglund's syndrome of the heel: Its effects on the dorsiflexion of the ankle and correlations to clinical and functional scores.

The Zadek osteotomy is a therapeutic option in Haglund' syndrome for patients with a X/Y ratio measurement of the calcaneus under 2.5. We hypothesized that Zadek osteotomy would lead to improvement in ankle dorsiflexion and functional scores. Twenty-two patients (mean age: 48.5 years) with Haglund's syndrome underwent a Zadek osteotomy and were enrolled in a prospective study investigating the proposed hypothesis. Radiological measurements included the X/Y ratio and the pitch angle. Measurements of the dorsiflexion of the ankle, using a hand-made frame, were performed twice by 2 independent observers. Inter and intra classes correlations were calculated. Functional results were assessed using AOFAS, EFAS and EFAS sport. Correlation between ankle dorsiflexion and functional scores were determined using linear regression curves. Our hypothesis was validated with a mean improvement of dorsiflexion of 7.27° (54.98% improvement from pre-operative measurement) (p < 0.0001). Ankle dorsiflexion measurements were highly reproducible with an interclass correlation coefficient(ICC)> 0.95 (0.98-0.99). All mean values of functional scores were significantly improved(p < 0.05) [AOFAS (61.95-94), EFAS (14-21.82), EFAS sport (7.68-13.69)] and were strongly correlated to the dorsiflexion values with a coefficient of determination of 0.82 for AOFAS and EFAS and of 0.86 for EFAS sport, respectively. The mean values of X/Y ratio and pitch angle improved from pre to postoperative conditions, 2.18-2.75 and 28.95-19.77° (p < 0.05), respectively. The angle correction obtained from modifiying the shape of the calcaneus, due to the Zadek osteotomy, confirms it as a safe and reliable treatment, with improvements of both ankle dorsiflexion and functional scores.