Early ultrasonographic evaluation of idiopathic clubfeet treated with manipulations, casts, and Botox(®): a double-blind randomized control trial

BACKGROUND: The manipulations, casts, and Botox(®) method for treating idiopathic clubfoot is an alternative non-surgical treatment method. Botox(®)-induced reversible muscle paralysis of the gastrocsoleus enables a physician to manipulate and cast the clubfoot in greater dorsiflexion. Ultrasound is incorporated during the early treatment stages to monitor the underlying physiology of the muscle–tendon unit following Botox(®). METHODS: Ultrasonographic evaluation was performed parallel to a double-blind randomized control trial administering Botox(®) or placebo to correct clubfoot. Patients underwent two-dimensional ultrasound to monitor the length changes to the gastrocsoleus and Achilles tendon unit at two time points: pre-injection (baseline) and 6 weeks post-blinded injection. Gastrocsoleus and Achilles tendon length measurements were analyzed among placebo, Botox(®) and contralateral controls using repeated measures ANOVA. RESULTS: The baseline gastrocsoleus length of the clubfoot (322.4 pixels) before blinded injection appears shorter than controls (337.5 pixels), but fails to reach significance (p = 0.05). The complex length within each of the three treatment groups displayed no significant change between baseline and 6 weeks. The complex–tendon ratio and muscle–tendon ratio of the Botox(®) treatment group was significantly decreased compared to controls (p = 0.049 and 0.042, respectively). Briefly, when expressed as a proportion, an increase in Achilles tendon length and decrease in gastrocsoleus is observed when clubfeet are treated with Botox(®). CONCLUSIONS: Only in the Botox(®) treatment cohort did the muscle shrink to uncover tendon (seen as a decreased complex–tendon ratio and muscle–tendon ratio) over the 6-week interval to effectively increase tendon length with respect to the unit as a whole. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11832-015-0633-4) contains supplementary material, which is available to authorized users.