Foot and Leg Problems

Abstract

Metatarsus Adductus Forefoot adduction, a common deformity in infants, can present a spectrum of severity. Unfortunately, the terminology used in the literature is confusing. Congenital metatarsus adductus is an intrauterine postural deformity of the forefoot. Congenital metatarsus varus is an intrauterine subluxation of the tarsometatarsal joint, with adduction of the metatarsals. The distinction is important because metatarsus adductus usually corrects spontaneously, whereas metatarsus varus will progress without active intervention. INCIDENCE AND ETIOLOGY Metatarsus varus occurs in about 1 per 1000 live births. There is no definable inheritance pattern. The risk of a second occurrence within a family is about 1 in 20. Pathogenesis has been studied by dissecting the feet of stillborn infants. This supports the concept of medial subluxation of the tarsometatarsal joints occurring while the foot is dorsiflexed. Adaptive changes of the bone and soft tissues occur secondarily. The incidence of congenital metatarsus adductus is unknown but is far more frequent than 1 per 1000 live births. The etiology is presumed to be a "packaging problem," with the forefoot compressed into adduction. Greater utilization and expertise with fetal ultrasound will help resolve these issues. DIAGNOSIS In congenital metatarsus adductus, the forefoot easily can be corrected passively to line up parallel to the heel and frequently can be overcorrected into abduction.