Surgical Management and Outcomes of Patients with Idiopathic Peroneal Spastic Flatfoot: A Retrospective Case Series.

[BACKGROUND] Although tarsal coalition represents the most common cause of peroneal spastic flatfoot, its existence cannot be verified in several cases. In some patients with rigid flatfoot, no cause can be detected after clinical, laboratory, and radiologic examination, and the condition is called idiopathic peroneal spastic flatfoot (IPSF). This study aimed to present our experience with surgical management and outcomes in patients with IPSF.

[METHODS] Seven patients with IPSF, who were operated on between 2016 and 2019, and followed for at least 12 months were included, whereas those with known causes, such as tarsal coalition or other causes (eg, traumatic) were excluded. All patients were followed up for 3 months with botulinum toxin injection and cast immobilization as a routine protocol, and clinical improvement was not achieved. The Evans procedure and grafting with tricortical iliac crest bone graft in five patients and subtalar arthrodesis in two patients were performed. The American Orthopaedic Foot and Ankle Society ankle-hindfoot scale scores and Foot and Ankle Disability Index scores were obtained preoperatively and postoperatively from all patients.

[RESULTS] On physical examination, all feet manifested rigid pes planus with varying degrees of hindfoot valgus and limited subtalar motion. Overall, the mean American Orthopaedic Foot and Ankle Society and Foot and Ankle Disability Index scores significantly increased from 42 (range, 20-76) and 45 (range, 19-68) preoperatively (P = .018) to 85 (range, 67-97) and 84 (range, 67-99) (P = .043) at the final follow-up, respectively. No major intraoperative or postoperative complications were observed in any of the patients. All computed tomographic and magnetic resonance imaging scans revealed no evidence of tarsal coalitions in any of the feet. All radiologic workups failed to demonstrate secondary signs of fibrous or cartilaginous coalitions.

[CONCLUSIONS] Operative treatment seems to be a good option in the treatment of patients with IPSF who do not benefit from conservative treatment. In the future, it is recommended to investigate the ideal treatment options for this group of patients.