Common Patterns of Congenital Lower Extremity Shortening: Diagnosis, Classification, and Follow-up

Abstract

Congenital lower limb shortening is a group of relatively rare, heterogeneous disorders. Proximal focal femoral deficiency (PFFD) and fibular hemimelia (FH) are the most common pathologic entities in this disease spectrum. PFFD is characterized by variable degrees of shortening or absence of the femoral head, with associated dysplasia of the acetabulum and femoral shaft. FH ranges from mild hypoplasia to complete absence of the fibula with variable shortening of the tibia. The development of the lower limb requires complex and precise gene interactions. Although the etiologies of PFFD and FH remain unknown, there is a strong association between the two disorders. Associated congenital defects in the lower extremity are found in more than 50% of patients with PFFD, ipsilateral FH being the most common. FH also has a strong association with shortening and bowing of the tibia and with foot deformities such as absence of the lateral rays of the foot. Early diagnosis and radiologic classification of these abnormalities are imperative for appropriate management and surgical planning. Plain radiography remains the main diagnostic imaging modality for both PFFD and FH, and appropriate description of the osseous abnormalities seen on radiographs allows accurate classification, prognostic evaluation, and surgical planning. Minor malformations may commonly be misdiagnosed.

Postaxial limb hypoplasia (PALH): the classification, clinical features, and related developmental biology

“…Stanitski et al . 13 reported that three-ray feet occurred in none of the type IA or type IB fibulae but 100% of type II fibulae. However, one patient (No.…”

“…However, FH often involves femoral and tibial hypoplasia, hypoplasia of the lateral femoral condyle and anteromedial bowing of the tibia, valgus or varus deformity of the ankle and deficiency of the lateral ray of the foot, balland-socket ankle joint deformity, and TC of the doi: 10.1111/nyas.13440 foot. 4,[12][13][14] The hypoplasia of the lateral femoral condyle and anteromedial bowing of the tibia could lead to genu valgum or knock-knee, and valgus or varus deformity of the ankle and deficiency of the lateral ray of the foot may preclude plantigrade walking. The term "postaxial hypoplasia" may be more appropriate in describing this disease as compared with the traditional terms FH or "fibular hypoplasia," since it mainly affects lower extremities.…”

“…Most limbs with type IA FH had five-ray feet, which were only detected in type IA FH patients. Stanitski et al 13 reported that threeray feet occurred in none of the type IA or type IB fibulae but 100% of type II fibulae. However, one patient (No.…”

“…PFFD is a musculoskeletal malformation in the proximal portion of the femur that is a result of early disturbance of growing mesenchymal homeostasis. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] The first PFFD case, reported in 1974 by Kelly, described a deformity of the right leg of an infant. 19 The classification of PFFD was described by Torode and Gillespie in 1991.…”

“…40 The appearance of limb buds, which are small projections of fetal mesenchymal condensation on the ventrolateral aspect of the trunk, occurs during the fourth to fifth weeks of gestation. 13 The development of the bud has intrinsic polarity and occurs along three different axes: proximal-distal (PD), anterior-posterior (AP), and dorsoventral (DV). The complex patterning process is regulated by three main signaling centers-the apical ectodermal ridge (AER), the zone of polarizing activity (ZPA), and the progress zone (PZ).…”