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 an IPSF, who were operated on between 2016 and 2019, and followed for at least 12 months were included, whereas those with known etiologies, such as tarsal coalition or other etiologies (traumatic, etc.) 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 5 patients and subtalar arthrodesis in 2 patients were performed. The American Orthopaedic Foot and Ankle Society ankle-hindfoot scale scores (AOFAS) and Foot & Ankle Disability Index (FADI) scores were obtained pre- and postoperatively from all patients.
Results: In physical examination, all feet manifested by rigid pes planus with varying degrees of hindfoot valgus and limited subtalar motion. Overall, the mean AOFAS and FADI scores significantly increased from 42 (range = 20-76) and 45 (range, 19-68) preoperatively (p = 0.018) to 85 (range = 67-97) and 84 (range, 67-99) (p = 0.043) at the final follow-up, respectively. No major intra- or post-operative complications were observed in any of the patients. All CT and MRI scans revealed no evidence of tarsal coalitions in any of the feet. All radiological workups failed to demonstrate secondary signs of fibrous or cartilaginous coalitions.
Conclusion: 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.