Achilles Pullout Strength After Open Calcaneoplasty for Haglund's Syndrome

Haglund's syndrome involves a prominent posterior superior prominence of the calcaneus. If nonoperative management fails, operative management with calcaneoplasty is often needed. No study has assessed Achilles tendon pullout strength after an open calcaneoplasty for Haglund's syndrome. The purpose of this study was to investigate those changes in a cadaveric model and provide objective data upon which to base postoperative recovery.

Seven matched pairs of cadaveric specimens (mid-tibia to toes) were divided into 2 cohorts: (1) intact/untreated and (2) open resection. The open resection group was treated with an open calcaneoplasty through a posterior approach using a microsagittal saw. We compared Achilles pullout strength between the 2 groups through the use of a mechanical testing system. Specimens were then loaded to failure. Lateral radiographs were obtained before and after surgery to quantify bone removal. Outcome measures included height of bony resection, angle of bone resection, and load to failure.

The mean maximum pullout strength was significantly higher in the intact specimens (1300 ± 500 N) compared to the open resection group (740 ± 180 N) ( P < .01), representing a 45% reduction in pullout force in the open resection group. Pullout force was significantly correlated to bone mineral density (BMD) ( P < .05). Pullout force was negatively correlated to both radiographic measures of resection level, angle, and height, but neither of these were significant.

Open calcaneoplasty demonstrated a significant weakness of the Achilles tendon insertion. Pullout strength of the Achilles was also positively correlated with BMD.

Biomechanical evidence presented above supports the practice of protected weightbearing and cautious return to activity after open calcaneoplasty for Haglund's syndrome.