Are there benefits of a 2D gait analysis in the evaluation of the subtalar extra-articular screw arthroereisis? Short-term investigation in children.

BACKGROUND

A juvenile flexible flatfoot is a common abnormality during growth. For children with a pathological manifestation, subtalar extra-articular screw arthroereisis is a popular operative technique. Although this minimally invasive operation technique has been performed for >45 years, complications still occasionally occur. For this reason, we created this pilot study to investigate whether a two-dimensional (2D) gait analysis is able to identify functional movement deficits after surgery.

METHODS

Fourteen children (27 ft) with a mean age of 12.38 years (SD, 1.40 years) were analyzed. Biomechanics were examined before and 4 weeks after surgery using a 2D gait analysis. For this purpose, the patients were filmed on a treadmill. In focus were static and dynamic recordings of the heel angle, rearfoot angle, and the leg axis angle. In addition, the step length and self-selected speed were measured.

FINDINGS: After surgery rearfoot angle showed significant reduction (p < 0.001) from 12.49° to 3.63° under static conditions and from 12.65° to 4.58° under dynamic conditions. Heel angle responded similar (p < 0.001). There were no significant differences in self-selected speed or step length. Undoubtedly, gait analysis was able to identify intraindividual deficits, leading to a closer monitoring of five patients and an adjustment of the screw in one foot.

INTERPRETATION: By means of the 2D gait analysis, we were able to show functional improvement after subtalar extra-articular screw arthroereisis. Nonetheless, we identified a few children who still had functional abnormalities. Certainly, it is unclear whether this additional examination is able to reveal all complications that would have occurred later.