Botulinum toxin injection combined with rehabilitation training for peroneal spastic flatfoot: A pilot case series

Peroneal spastic flatfoot (PSFF) involves peroneal spasm and subtalar restriction, yet optimal conservative care is undefined. This pilot retrospective study explored the preliminary outcomes of botulinum toxin type A (BoNT-A) injection combined with rehabilitation in 19 PSFF patients (10 with structural abnormalities [SA], 9 without [NSA]). Pain (VAS), spasticity (MAS), and function (AOFAS-AH) were assessed at baseline, 1, 3, and 6 months. Significant improvements were observed across all metrics (P < 0.05). The median VAS decreased from 4 to 0, median AOFAS-AH improved from 67 to 100, and median MAS reduced from grade 4 to grade 0 at 6 months relative to baseline. In subgroup comparisons, NSA patients achieved superior outcomes, with significantly higher AOFAS-AH and lower MAS at 3 and 6 months (P < 0.05) and 100% satisfaction versus 40% in SA patients (P < 0.05). One patient experienced transient calf swelling. These exploratory findings suggest BoNT-A combined with rehabilitation may warrant further investigation as a potential conservative option for PSFF, particularly among patients without structural abnormalities. Due to the small sample size and lack of control group, these results should be interpreted as exploratory rather than confirmatory. LEVEL OF EVIDENCE: Level IV, retrospective case series.