Pediatric orthopedic cases 27

CASE                               27                               

 

A healthy, 9-month-old baby is brought in by her parents. At birth, it was noted that she only had three toes on the left foot. It appears the lateral two rays are absent. Radiographs of both feet are shown (Figs. 10–44 and 10–45). The left leg appears well formed but the entire lower extremity is slightly shorter compared to the other side.

 

Figure 10–44

 

 

Figure 10–45

 

How do you counsel the parents? (Figs. 10–44 and 10–45)

1. Absence of the lateral rays will unlikely affect her function

2. Absence of lateral ray(s) is associated with fibular deficiency

3. She will require an amputation in the future

4. She should be evaluated for cervical spine anomalies

 

Discussion

The correct answer is (B). Absence of lateral ray/rays of the foot is typical of fibular deficiency. Fibular deficiency is a spectrum of congenital malformations affecting postaxial limb development. Findings include absence of lateral rays of the foot, coalitions of the foot, ball and socket ankle, varying degrees of shortening or even absence of the fibula, as well as tibial shortening and genu valgum. Fibular deficiency is often associated with some degree of shortening of the femur as well.

The full-length lower extremity radiograph of the child is shown (Fig. 10–46). The difference in tibial lengths is approximately 2 cm. All of the following are true EXCEPT:

 

 

 

Figure 10–46

1. This small length difference will remain the same or even improve with growth

2. This difference in tibial lengths will increase with growth

3. The calculated leg length difference at skeletal maturity is most important

4. Amputation is indicated for projected leg length discrepancies greater than 30%

 

Discussion

The correct answer is (B). Congenital leg length discrepancies will increase with growth. Projected length discrepancy is most important in determining the best treatment option. Patients with large projected length discrepancies, especially those greater than 30% of the contralateral limb, are best served with a Syme or Boyd amputation and prosthetic fitting. Patients with a nonfunctional foot may also be better served with an amputation.

 

Objectives: Did you learn...?

 

Fibular deficiency is a congenital longitudinal deficiency involving abnormalities of the fibula, tibia, ankle, foot, and often the femur as well?

 

Projected leg length discrepancy at skeletal maturity is very important in determining treatment options?

 

Mild to moderate leg length differences associated with a functional foot and ankle may be treated with contralateral epiphysiodesis or limb lengthening?

 

Very large projected length discrepancies (over 30% of the contralateral side) are treated with amputation and prosthetic fitting?