- Discussion:
- in polio, paralytic equinovalgus deformity results from paralysis of tibialis anterior and posterior, together w/ unopposed action of peronei and triceps surae;
- os calcis is everted and is displaced laterally and posteriorly;
- sustentaculum tali can no longer function as calcaneal buttress for talar head, which shifts medially and into equinus;
- hindfoot and forefoot equinovalgus deformity rapidly develop and with growth the deformity becomes fixed;
- w/ triple arthrodesis (Grice) goal is restoration of medial longitudinal arch;
- in ideal situation, valgus deformity is localized to sub-talar joint & calcaneus can be manipulated into its normal position beneath the talus;
- procedure is contraindicated unless the forefoot is sufficiently mobile to be made plantigrade when the hindfoot is corrected;
- failure to heed this precaution results in the development of painful callus over the fifth metatarsal head