Pediatric orthopaedic cases 24

CASE                               24                               

A healthy, 1-month-old baby is brought to see you because the right lower extremity is shorter than the left. This was noticeable at birth. The baby is otherwise healthy and growing normally. Examination shows a healthy infant with a shortened and bulbous right thigh with palpable flexion deformity at the proximal thigh. The right lower extremity is externally rotated and abducted compared to the left. An x-ray taken at the visit is shown (Fig. 10–43).

 

 

 

Figure 10–43

 

Based on the clinical examination and radiograph the correct diagnosis is:

1. Healing femoral shaft fracture

2. Proximal femoral focal deficiency (congenital femoral deficiency)

3. Congenital coxa vara

4. Osteogenesis imperfect

 

Discussion

The correct answer is (B). The described clinical examination and radiograph are consistent with proximal femoral focal deficiency (PFFD), also known as congenital femoral deficiency. This is a condition involving abnormal development of the acetabulum and proximal femur. The condition demonstrates variable degrees of severity. In its most severe form the acetabulum, femoral head and most of the femur is absent. A subtrochanteric deformity including flexion, abduction, and

external rotation is present and distinguishes this from congenital coxa vara.

 

PFFD is commonly associated with all the following congenital anomalies EXCEPT:

1. Fibular deficiency

2. Other limb anomalies

3. Absent cruciate ligaments

4. Congenital vertical talus

 

Discussion

The correct answer is (D). PFFD is commonly associated with all of the above except for congenital vertical talus. Some degree of fibular deficiency (fibular hemimelia) is seen in the majority of patients with PFFD. Many are also found to have other limb anomalies. Absence of cruciate ligaments is the rule in both PFFD and fibular deficiency. Congenital vertical talus is not specifically associated with PFFD.

Prior to undertaking a femoral lengthening in a patient with PFFD, the following requirement must be met:

1. Stability of the hip joint via pelvic and/or proximal femur osteotomies when necessary

2. Projected leg length discrepancy over 30 cm

3. Reconstruction of the cruciate ligaments of the knee

4. Age 8 or greater

 

Discussion

The correct answer is (A). Prior to a planned femoral lengthening in PFFD, the hip joint must be stable or surgically stabilized to prevent hip dislocation while lengthening. A projected leg length discrepancy over 30 cm would be a contraindication for lengthening. Reconstruction of the deficient cruciate ligaments is not routinely carried out, but the knee joint must be stabilized externally during lengthening so as not to dislocate. Lengthening is often carried out at ages much younger than 8, especially if multiple lengthenings are planned due to large leg length discrepancies.

 

Objectives: Did you learn...?

 

Proximal femoral focal deficiency is an uncommon congenital anomaly resulting

in varying degrees of under-development or even absence of the acetabulum and proximal femur?

 

PFFD is often associated with other extremity anomalies?

 

In the majority of cases, PFFD is associated with some degree of fibular deficiency?

 

Amputation as well as hip reconstruction and femoral lengthening are treatment options depending on the degree of shortening of the affected extremity?