|
Year |
2002 |
|---|---|
|
Question Number |
25. |
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Category |
Pediatric Orthopaedics |
Question
Radiographs of an adolescent who had metatarsus adductus as an infant that was refractory to treatment may show which of the following findings?
1- Obliquity of the medial cuneiform
2- Superior placement of the tarsal navicular on the head of the talus
3- Medial subluxation of the cuboid
4- Lateral subluxation of the middle and lateral cuneiforms.
5- Coalition of the cuboid and calcaneus
Figures
Answer (click for answer)
Preferred Response: 1
Metatarsus adductus is a congenital deformity of the foot with and incidence of 1:1000. There is no exact etiology or sexual predilection. Factors thought to cause the deformity include increased intrauterine pressure, intrauterine positioning, multiple gestations, muscle hyperactivity, anomalous muscle insertions, and possibly even the absence of the medial cuneioform. Hallux valgus is a commonly associated deformity.
Metatarsus adductus is an osseous deformity consisting of a medial deviation of all metatarsals in the transverse plane. The condition is further classified into a passively correctable deformity or rigid deformity. Treatment remains controversial with some advocating no treatment for passively correctable deformities to at trial of treatment with manipulation and serial casting. Other options include surgical procedures for operative correction. These procedures may be technically demanding and there is also disagreement regarding the appropriate age for operative intervention.
Radiographic anomalies include medial deviation of all the metatarsals and increased adduction of the hallux. Obliquity of the medial cuneiform and first metatarsocuneioform joint may also be present on anterior-posterior radiographs. Some others have suggested that this obliquity is a marker indicative of surgical correction. A recent long-term follow-up study demonstrated this obliquity in twenty-one of thirty-one feet examined at an average of 32 years and six months.
A recent histological analysis of two fetuses with congenital metatarsus adductus at 16 and 19 weeks gestation demonstrated an altered appearance of the medial cuneioform with a medial tilt to the cuneometarsal joint. The authors observed no subluxation at any of the other cuneometatarsal or naviculocunieform joints, and the navicular showed no signs of medial or lateral displacement in relation to the head of the talus.
Reference: Farsetti P, Weisntein SL, Ponseti IV. The long-term functional and radiographic outcomes of untreated and non-operatively treated metatarsus adductus. J Bone Joint Surg Am 1994;76:257-265.
Marcinko DE, Hetico HR: Structural metatarsus adductus deformity: Surgical case report. J Foot Surg 1992;31:607-610.
Morcuende JA, Ponseti IV: Congenital metatarsus adductus in early human fetal development: A histologic study. Clin Orthop 1996;333:261-266.