Revisiting Subtalar Screw Arthroereisis (SSA) for the Treatment of Flexible Flatfoot in Children

Objective:
Subtalar arthroereisis has been reported to be an effective treatment technique for flexible flatfoot (FF) in children. Although many devices for this procedure exist, arthroereisis using screws is still globally used. The aim of this study is to revisit subtalar screw arthroereisis (SSA) and investigate its outcomes.

Methods:
Data of 397 patients who underwent SSA between 2009 and 2020 at our institution were retrospectively reviewed. After the exclusion of rigid flatfoot cases, analysis yielded 339 cases of FF - bilaterally in 169 patients and monolaterally in 1 patient, with a median follow-up of 48 months. The average age of the patient cohort at the time of the implantation was 11.9 years (range 5.6-14.7 years). Data were analyzed using Pearson`s chi-squared test and Student t-test.

Results and Conclusion:
Average duration of monolateral SSA was 19.5 minutes. Intraoperative complications were seen in 0.58% of all cases. Average hospital stay was 3.8 days for bilateral SSA. Screws were explanted after a median of 46 months. Although 39.5% of patients experienced postoperative local pain, 96.75% of the study cohort reported direct postoperative satisfaction with outcome. Postoperative complications which mostly included wound healing disorder and peroneal irritation were seen in 5% of all cases, 0.58% of which required surgical revision. Weak statistically significant (p<0.05) correlations were observed between gender and postoperative pain and complications. Patient age and weight at the time of the implantation demonstrated significant statistical correlation (p<0.05) to postoperative complications and surgical revisions. The values of the pre- and post-SSA weight-bearing radiographic angles were 15.7° ± 4.3° and 17.9° ± 4.7°, respectively, for the calcaneal pitch, 137° ± 7.9° and 127° ± 10°, respectively, for the Costa-Bartani angle, 36.6° ± 6.6° and 32.5° ± 6.3°, respectively, for the talar declination angle, 22° ± 8.2° and 14.7° ± 8.3°, respectively, for the lateral talometatarsal angle, 28.9° ± 6.6° and 26.4° ± 7.3°, respectively, for the anteroposterior talocalcaneal angle and 13.7° ± 7.4° and 11° ± 7.7°, respectively, for anteroposterior talometatarsal angle (p<0.001).

In conclusion, SSA for treatment of FF in children showed excellent results in terms of improved clinical aspects and radiographic measurements. Nevertheless, accurate indication for surgical treatment is necessary.