Metatarsus adductus is a congenital deformity of the foot where there is increased curvature of the forefoot. This gives the foot the appearance of a "C" shape. This deviation of the metatarsals or visual effect of in-toeing is a deformity that occurs at the midfoot of the foot. The diagnosis of metatarsus adduction is relatively straightforward and is predominantly a clinical diagnosis. The exact cause of metatarsus adductus is not fully understood but is considered to be caused by intrauterine position and pressures. There may also be a genetic component to the deformity.
The diagnosis of metatarsus adductus is made by physical examination and has certain characteristics:
- the foot has an inward position as compared to the lower leg
- the foot has a concave border medially and a convex border laterally
- the metatarsus adductus foot may appear with a high arch
- there is usually a separation of the big toe from the lesser toes
Non Operative Treatment
Most children with the metatarsus adductus deformity can be treated with conservative measures. Mild flexible cases can be treated with stretching and strengthening modalities, braces, orthoses, or straight last or reverse last shoe gear. In some cases serial casting may be necessary. This consists of applying plaster to the foot reducing the deformity. The cast is changed every 7 to 14 days. Casting is recommended until the deformity is reduced and then for half the amount of time again. In other words if it takes 6 weeks of casting to reduce the deformity then the infant should be cast for an additional three weeks. In those children who require casting those treated prior to the age of ambulation have more favorable results, but that doesn't mean that those with the deformity shouldn't be treated after ambulation begins. In cases where the deformity is resistant to conservative treatment or the deformity is rigid, surgical treatment may be considered.
Operative treatment is reserved for deformities that have been neglected or have not responded to non-operative treatments. If surgery is required there are several different procedures depending on the age of the patient and the magnitude of the deformity. In less severe cases, soft tissue releases or tendon transfers can correct the deformity. While in more severe cases bony cuts and repositioning is the best treatment option. Following any type of surgical correction braces, orthoses or orthopedic shoes may be required.