Background: In children with cerebral palsy (CP), overactivity of the peroneus longus (PL) muscle is a major contributor to pes planovalgus. This retrospective study assessed whether abobotulinumtoxinA injections into a PL showing premature activity on electromyography (EMG) clinically improved foot morphology in children with CP. Methods: Study participants were <. 6 years old, had a diagnosis of CP, good functional abilities (Gross Motor Function Classification System level 1 or 2), equinovalgus (initial contact with the hallux or head of the first metatarsal) and overactive PL on EMG. The fore-, mid- and hindfoot were evaluated clinically and radiologically before and after injection of abobotulinumtoxinA (6-7 U/kg) into the PL. Radiological data were compared with reference values for children without pes planovalgus. Results: In total, 16 children (8 males; 10 hemiplegia, 6 diplegia; mean age: 3.2. ±. 1.5 years) received treatment. Mean pre-and post-treatment angles in clinical assessment of dorsiflexion of the talocrural articulation did not differ with both knees flexed (24.4. ±. 7.5 vs. 22.2. ±. 8.0 degrees; P=. 0.19) or extended (17.2. ±. 8.0 vs. 16.6. ±. 6.8 degrees; P=. 0.36). Radiographic data pre-treatment versus reference data revealed forefoot pronation (metatarsal stacking angle 2.1. ±. 8.3 vs. 8.0. ±. 2.9 degrees; P=. 0.002), midfoot planus (lateral talo-first metatarsal 28.5. ±. 15.0 vs. 13.0. ±. 7.5 degrees; P<. 0.001; talocalcaneal angle 54.6. ±. 8.6 vs. 49.0. ±. 6.9 degrees; P=. 0.004) and significantly decreased calcaneus dorsiflexion, without hindfoot equinus (calcaneal pitch angle 7.9. ±. 6.0 vs. 17.0. ±. 6.0 degrees; P<. 0.001). After treatment, the metatarsal stacking angle did not differ from reference values (. P=. 0.15). As compared with before treatment, treatment improved mean angles for metatarsal stacking (2.1. ±. 8.3 vs. 7.1. ±. 3.9 degrees, respectively, P=. 0.002), lateral talo-first metatarsal and talocalcaneal (both P<. 0.001), with no change in the hindfoot. Conclusion: PL may be an early target for abobotulinumtoxinA treatment in pes planovalgus associated with premature PL activity in children with CP.
Boulay, C., Jacquemier, M., Castanier, E., Giorgi, H., Authier, G., Pomero, V., … Viehweger, E. (2015). Planovalgus foot deformity in cerebral palsy corrected by botulinum toxin injection in the peroneus longus: Clinical and radiological evaluations in young children. Annals of Physical and Rehabilitation Medicine, 58(6), 316–321. https://doi.org/10.1016/j.rehab.2015.09.001