Rickets Imaging 

Rickets is an entity in which mineralization is decreased at the level of the growth plates, resulting in growth retardation and delayed skeletal development. Osteomalacia is found within the same spectrum, affects trabecular bone, and results in undermineralization of osteoid bone.

The term rickets is said to have derived from the ancient English word wricken, which means "to bend." In several European countries, rickets is also called English disease, a term that appears to stem from the fact that at the turn of the 19th century, rickets was endemic in larger British cities.

By definition, rickets is found only in children prior to the closure of the growth plates, while osteomalacia occurs in persons of any age. Any child with rickets also has osteomalacia, while the reverse is not necessarily true.^{[1, 2, 3]}

See the images of rickets below.

Clinical findings are related to the involved skeletal site, as shown in the image below.

Preferred examination

Plain radiography of the affected bones is the preferred examination. The distal radius and ulna typically demonstrate rachitic lesions early on radiographs. In preterm neonates and young infants, radiographs of the knee may be more reliable than those of the wrist. In the early stage of rickets, radiographs depict no pathology; however, chemical changes in blood serum can already be found at this time.^{[4, 5, 6, 7]}

Plain radiograph findings include the following:

• Widening and cupping of the metaphyseal regions (see the image below)Anteroposterior and lateral radiographs of the wrist of an 8-year-old boy with rickets demonstrates cupping and fraying of the metaphyseal region.
• Fraying of the metaphysis (see the images below)Radiographs of the knee of a 3.6-year-old girl with hypophosphatemia depict severe fraying of the metaphysis. Radiograph in a 4-year-old girl with rickets depicts bowing of the legs caused by loading.
• Craniotabes
• Bowing of long bones (see the images below)Radiograph in a 4-year-old girl with rickets, focused on the knees. Image depicts the development of knock-knees. Radiograph of the proximal humerus in a 2.5-year-old girl who had a peripheral neuroectodermal tumor of the right brachial plexus. After treatment with ifosfamide, the patient developed rickets of the proximal femur. In this case, metastasis should be incorporated into the differential diagnosis. Radiograph of the knees of an 11-year-old boy with treated vitamin D–resistant rickets. Image demonstrates bilateral multiple growth arrest lines and underdevelopment of the medial aspect of both the tibial plateau and the femoral condyle.
• Development of knock-knees, or genu valgum (see the image below)Radiograph of a leg with the patient in a standing position demonstrates knock-knees. The patient is an 11-year-old boy with treated vitamin D–resistant rickets.
• Development of scoliosis
• Impression of the sacrum and femora into the pelvis, leading to a triradiate configuration of the pelvis
• In healing rickets, the zones of provisional calcification become denser than the diaphysis. In addition, cupping of the metaphysis may become more apparent.

A useful mnemonic for remembering the findings of rickets is as follows:

• Reaction of the periosteum (may occur)
• Indistinct cortex
• Coarse trabeculation
• Knees, wrists, and ankles affected predominantly
• Epiphyseal plates, widened and irregular
• Tremendous metaphysis (cupping, fraying, splaying)
• Spur (metaphyseal)

In more advanced stages of rickets, radiographic changes are pathognomonic; however, the underlying cause needs to be established using clinical and biochemical assessments. False-negative findings can occur in the early phase of disease.