Joint preservation surgery for correcting adolescents’ spasmodic flatfoot deformity: early results from a specialized North African foot and ankle unit

We aimed to report early results of performing joint-preserving surgeries for managing spasmodic flatfoot deformity (SFFD) in adolescents.

A prospective case series study including 24 patients (27 feet) diagnosed with idiopathic SFFD not responding to conservative management. After reassessment under anesthesia, surgical procedures included soft tissue releases (Achilles tendon (AT), peroneus brevis (PB), peroneus tertius (PT) (if present), and extensor digitorum longus (EDL)), bony osteotomies (lateral column lengthening (LCL), medial displacement calcaneal osteotomy (MDCO), and double calcaneal osteotomy (DCO)), and medial soft tissue reconstruction or augmentation if needed. Functional evaluation was performed per the American Orthopedic Foot and Ankle Society (AOFAS) score, while radiological parameters included talo-navicular coverage angle (TNCA), talo-first metatarsal angle (AP Meary’s angle), calcaneal inclination angle (CIA), talo-calcaneal angle (TCA), talo-first metatarsal angle (Lat. Meary’s angle), and tibio-calcaneal angle (TibCA). The preoperative parameters were compared to the last follow-up using the Wilcoxon signed test.

The mean age was 15.37 ± 3.4 years, 18 (75%) were boys, and the mean BMI was 28.52 ± 3.5 (kg/m²). Release of AT and fractional lengthening of PL, PT, and EDL were performed in all patients. LCL was needed in eight feet (29.6%), MDCO in 5 (18.5%), and DCO in 14 (51.9%). FDL transfer was required in 12 (44.4%) feet, and repair of the spring ligament in seven (25.9%). The mean operative time was 99.09 ± 15.67 min. All osteotomies were united after a mean of 2.3 ± 0.5 months. After a mean follow-up of 24.12 ± 8.88 months (12 and 36 months), the AOFAS improved from a preoperative mean of 43.89 ± 11.49 to a mean of 87.26 ± 9.92 (P < 0.001). All radiological parameters showed significant improvement, AP Meary’s angle from a mean of 20.4 ± 5.3 to a mean of 9.2 ± 2.1, Lat. Meary’s angle from − 15.67° ± 6.31 to − 5.63° ± 5.03, TNCA from − 26.48° ± 5.94 to 13.63° ± 4.36, CIA from 12.04° ± 2.63 to 16.11° ± 3.71, TibCA from − 14.04° ± 3.15 to − 9.37° ± 3.34, and TCA Lat. from 42.65° ± 10.68 to 25.60° ± 5.69 (P ≤ 0.001). One developed wound dehiscence (over an MDCO), managed with daily dressings and local antibiotics. Another one developed lateral foot pain after having LCL managed by metal removal.

Careful clinical and radiological evaluation for the correct diagnosis of SFFD is paramount. Joint-preserving bony osteotomies combined with selective soft tissue procedures resulted in acceptable functional and radiological outcomes in this young age group.