Interference Screw vs Suture Button Fixation for Tibialis Anterior Tendon Transfer to Lateral Cuneiform: A Biomechanical Analysis with Implications for Clubfoot Treatment

CATEGORY: Other INTRODUCTION/PURPOSE: While transfer of the tibialis anterior tendon (TAT) to the lateral cuneiform (LC) following serial casting has been used for over 60 years to treat relapsed clubfoot deformity, modern methods of tendon fixation remain largely unstudied. Though interference screw fixation has the potential of obviate concerns of pressure necrosis and proper tendon tensioning associated with plantar button suspensory stabilization, a better understanding of LC morphology in young children is a necessary first step in assessing the viability of this fixation technique. The purpose of this investigation is therefore to define LC morphology in children aged 3-6 years. METHODS: A retrospective radiographic review of 40 healthy pediatric feet aged 3-6 years who had either MRI or CT scans was performed at a single pediatric hospital. The length, width, and height of only the ossified portion of the LC were measured digitally using sagittal, coronal, and axial imaging. In addition, the maximal cross-sectional diameter of the TAT was measured at the level of the tibiotalar joint. RESULTS: Average ossified LC width ranged from 8.5mm in the 3-year-old cohort to 10.3mm in 6-year-old children. While the average width increased with each year of age, ANOVA testing revealed no statistically significant difference in width between age groups (p=0.091). Average ossified LC length ranged from 13.5mm in the 3-year-old cohort to 18.3mm in 6-year-old children with statistically significant increases in all age groups separated by two or more years (p=0.017). the TAT to ossified LC width ratio ranged from 44% to 53% across age groups. (table 1). CONCLUSION: The dimensions of the LC ossification center are large enough to allow interference screw fixation in children 3 to 6 years of age.