Sixteen hemiplegic (3.25 years ± 1.5), GMFCS 1 or 2, with a planovalgus foot deformity during the stance phase and, during SW, a dynamic equinus with hindfoot valgus and a premature overactivity of PL were treated by a BoNT-A injection (Dysport®,Ipsen) into PL. Radiological foot parameters measured forefoot pronation, midfoot planus, valgus and equinus of hindfoot. These parameters are validated in the healthy and hemiplegic children. A paired t-test compared for each angle the pre and post-toxin measurement.
The parameters described between pre-toxin vs normal data: calcaneal-pitch (8°vs 17°P < 0.001), talocalcaneal angle (55°vs 49°P < 0.05),lateral talo-first metatarsal angle (29°vs 13°P < 0.001) and metatarsal-stacking angle (2°vs 8°P < 0.001). There was a non-significative difference, between pre vs post-toxin, for the calcaneal-pitch angle (7°vs 9°) and the anteroposterior ankle angle(14°vs 15°P < 0.05). There was a significative difference, between pre vs post-toxin, for the talocalcaneal angle (55°vs 46°P < 0.001), the lateral talo-first metatarsal angle (29°vs 18°P < 0.01) and the metatarsal stacking angle (2°vs 7°P < 0.001).
Before injections, the radios showed a hindfoot valgus, a dorsalflexed calcaneus with midfoot planus and a forefoot pronation. After injections, midfoot planus is reduced by the decrease of talus subluxation and there was not forefoot pronation. Injections into PL seemed to have a therapeutic actions on fore and midfoot that improved clinically the hindfoot valgus but without action on the dorsalflexed of calcaneus depending on the gastrocsoleus complex. PL could be an early therapeutic target for BoNT-A in planovalgus.