Radiography, CT, and MRI of Hip and Lower Limb Disorders in Children and Adolescents

Abstract

Infants and children are vulnerable to congenital and developmental hip and lower extremity disorders. These disorders have diverse causes in pediatric patients, and owing to potential related complications that can lead to degenerative disease in adulthood, an accurate diagnosis is essential. A common disease is developmental dysplasia of the hip, which affects nearly 1% of newborns. This condition is best evaluated with US and conventional radiography. Slipped capital femoral epiphysis affects approximately 0.01% of young teenagers and is initially evaluated with radiography. Femoroacetabular impingement is a risk factor for early osteoarthritis and can be assessed with radiography, CT, or MRI. Limb length discrepancy is defined as a greater than 2-cm difference in length between paired bilateral lower extremities. There are several methods of measuring this difference, and the use of an accurate imaging modality is essential for treatment. Developmental bowing is a physiologic condition involving varus angulation of the knee and is best evaluated by using conventional radiography. Blount disease is a progressive pathologic genu varum centered at the tibia; the three subtypes are infantile, juvenile, and adolescent. In-and out-toeing disorders are caused by abnormal tibial and femoral torsion that usually self-corrects during lower limb growth. The ability to recognize these conditions is essential for differentiating those that will resolve spontaneously versus those that will require treatment. The imaging features of congenital and developmental hip and lower extremity disorders are reviewed, with emphasis on diagnosis, radiologic assessment, associated findings, and classification. ©

Pediatric Pelvis

“…The Shenton line (arc) can be traced along the inferior border of the superior pubic ramus and inferomedial border of the femoral neck. Disruption of the Shenton line in a young pelvis may be due to hip subluxation or dislocation, particularly in the setting of DDH, 11 or in the older patient, a femoral neck fracture. 2 The iliopectineal line delineates the anterior column of the pelvis and extends from the medial margin of the iliac wing, continuing along the superior margin of the superior pubic ramus to the pubic symphysis.…”

Performance of Tönnis triple osteotomy in older children with developmental dysplasia of the hip (DDH) assisted by a 3D printing navigation template

“…Developmental dysplasia of the hip (DDH) is one of the common lower limb deformities in pediatric orthopaedics. It has a high disability rate and seriously affects the physical and mental health of pediatric patients [ 1 – 3 ]. Children with developmental dislocation of the hip (DDH) require personalized treatment, based on their ages and pathological characteristics of the hip [ 4 ].…”

Quantification of femoral position on radiographic acetabular coverage in children

“…Anteroposterior (AP) pelvic radiography is the first‐line imaging modality for diagnosing hip disorders in pediatric orthopedics, which can be used to evaluate the acetabulum‐head relationship (i.e., acetabular coverage) 1–3 . An accurate assessment of the radiographic acetabular coverage is essential for clinical diagnosis or surgical decision‐making in hip disorders such as developmental dysplasia of the hip (DDH) 4,5 .…”

“…Here we report the Mimics-based Local-rotation Fluoroscopy Simulation method to quantify the effect of femoral motion on acetabular coverage. The objectives of this study were (1) to evaluate the effect of femoral motion in different planes on acetabular coverage, (2) to identify the tolerance of the radiographic acetabular coverage to femoral motion, and (3) to predict the actual acetabular coverage from nonstandard radiographs. We hypothesized that the radiographic acetabular coverage would be affected by femoral motion.…”