Metatarsus Adductus

By admin On Feb 11, 2024

Ovid: 5-Minute Orthopaedic Consult

Editors: Frassica, Frank J.; Sponseller, Paul D.; Wilckens, John H.

Title: 5-Minute Orthopaedic Consult, 2nd Edition

> Table of Contents > Metatarsus Adductus

Metatarsus Adductus

Paul D. Sponseller MD

Basics

Description

Metatarsus adductus is a deformity in which the forepart of the foot is adducted or medially deviated (Fig. 1); the heel is in neutral or mild valgus position.
The most common foot condition seen by those caring for children
It appears in the newborn.
Classification (1) is based on flexibility: Flexible (correctable with manipulation) or rigid (a continuum)
Degree of deformity:
- Based on heel bisector method: The line
  bisecting the heel is drawn by visual examination of the foot’s sole;
  it normally crosses between 2nd and 3rd toes.
  - Mild: Heel bisector crosses the 3rd toe.
  - Moderate: Heel bisector crosses between the 3rd and 4th toes.
  - Severe: Heel bisector crosses between the 4th and 5th toes.
Synonyms: Metatarsus varus; Pes varus; Metatarsus internus; Hooked forefoot; Z-foot or C-foot

Fig. 1. Metatarsus adductus is characterized by a deviated forefoot but a normal hindfoot and ankle.

General Prevention

No effective means of preventing this deformity exist.

Epidemiology

Incidence

1–10 per 1,000 infants (2)
Equally distributed between males and females

Risk Factors

Family history
Hip dysplasia

Genetics

The risk is higher for those with 1st-degree relatives who have metatarsus adductus.

Etiology

Unknown
No association with birth order, gestational age, or maternal age
Most accepted theory: Metatarsus adductus is a possible result of tight intrauterine packing.

Associated Conditions

DDH of the hip occurs in 1–5% of patients with metatarsus adductus (2).

Diagnosis

Signs and Symptoms

Adduction (medial deviation) of the forefoot, with various degrees of supination
- Concave medial border and convex lateral border of the foot is seen, with prominence at the base of the 5th metatarsal.
The heel is in neutral or slightly valgus position, but not in equinus (foot-down).
The flexible deformity may persist until 1–2 years of age.
Most feet (86% in 1 study) become normal, 10% are mildly adducted, and 4% remain adducted without treatment (2,3).
In another natural history study (3), no patients had foot problems when treated with observation alone.
A deep medial crease suggests moderate deformity.

Physical Exam

Determine the flexibility of the forefoot adduction by trying to correct it.
Determine the ankle ROM.
The forefoot is deviated medially but flexible.
The hindfoot is normal, and the foot may be dorsiflexed to a flat position.
Also check the hips for dysplasia.

Tests

Imaging

Radiographic evaluation is unnecessary for most patients.
If congenital anomalies are suspected or the foot is stiff, AP and lateral views of foot may be obtained.

Pathological Findings

All structures of the foot are normal, except for the forefoot, which is deviated medially.

Differential Diagnosis

Clubfoot (heel varus and foot equinus):
- More rigid
- Whole foot turned inward

P.261

Treatment

General Measures

This condition resolves spontaneously in most patients.
Parents should be educated about this deformity.
Medical treatment:
- Most children with metatarsus adductus at birth do not require treatment.
- For severe unresolving deformity, serial manipulation and casting may be offered.
- The appropriate age at which to start casting is usually 6–12 months.
- It is appropriate to wait longer if the parents are willing because most feet will improve spontaneously with time.
- The duration of cast treatment is several months.
- Children may be placed in straight- or reverse-last shoes for several months after the foot is straightened by cast treatment.
- Because most of these feet improve spontaneously, early cast treatment before 6 months is not recommended.

Activity

Patients may participate in weightbearing activity as tolerated.

Special Therapy

Physical Therapy

Stretching of the foot is recommended for patients with a flexible deformity.
- Parents may perform this stretching during diaper changes.

Surgery

Surgery is an option, but it is rarely indicated.
- Only for children >4 years old who have residual metatarsus adductus
Procedures include the following:
- Lateral shortening osteotomy
- Medial cuneiform opening wedge osteotomy

Follow-up

Prognosis

>95% patients with mild and moderate deformity have done well in long-term, follow-up studies (3).
It is controversial whether the flexibility of the foot predicts prognosis.

Complications

Failure to correct the deformity completely (uncommon)
AVN of the cuneiform

Patient Monitoring

Frequency of follow-up varies by the individual.
It should be more frequent in patients with moderate and severe deformity and in those undergoing treatment.

References

1. Cook
DA, Breed AL, Cook T, et al. Observer variability in the radiographic
measurement and classification of metatarsus adductus. J Pediatr Orthop 1992;12:86–89.

2. Kasser
JR. The foot. In: Morrissy RT, Weinstein SL, eds. Lovell and Winter’s
Pediatric Orthopaedics, 6th ed. Philadelphia: Lippincott Williams &
Wilkins, 2006:1257–1328.

3. Farsetti
P, Weinstein SL, Ponseti IV. The long-term functional and radiographic
outcomes of untreated and non-operatively treated metatarsus adductus. J Bone Joint Surg 1994;76A:257–265.

Miscellaneous

Codes

ICD9-CM

754.53 Metatarsus adductus

Patient Teaching

Stress the benign nature of this condition.
Even if a mild degree of adduction persists, it has no functionally negative consequences.

FAQ

Q: What problems could arise from untreated metatarsus adductus?

A:
In most patients, the adduction resolves if given enough time. The only
possible sequelae relate to the fitting of shoes in a minority of
patients.