The knee has various pathologic appearances in patients with congenital longitudinal deformities of the lower extremities. Radiographs from 39 patients with unilateral longitudinal congenital deficiencies of the lower extremities were analyzed to describe epiphyseal and metaphyseal configurations and position of the epiphyseal plate. We defined 22 radiographic parameters of the femur and tibia, calculated the mean values, and compared the parameters of the affected knee with the unaffected knee for patients in different age groups. In the femur, we observed hypoplasia of the lateral condyle in width and height. In the tibia, the lateral condylar hypoplasia was manifest primarily by lateral horizontal deficiency. Age group comparisons showed no horizontal epiphyseal deficiencies in the older patients, but there was persistence of vertical epiphyseal deficiencies. Bony deformities in congenital longitudinal deficiencies mainly were attributable to dysplasia of the lateral epiphysis in the distal femur and proximal tibia, whereas positions of the epiphyseal plate had varying physiologic values.
Level of evidence: Diagnostic study, Level II. See the Guidelines for Authors for a complete description of levels of evidence.