Childhood fractures: When to worry

Childhood bone fractures are common and often cause concern for patients, parents and clinicians. Understanding the typical timing and types of fractures is helpful when deciding who needs further evaluation for potential underlying disease.

The rate of fractures increases substantially during puberty for both boys and girls, but to a greater degree for boys. The peak incidence of fractures in girls occurs around 10 to 12 years of age and in boys around 13 to 15 years of age.

Distal radius after injury

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Subsequent normal bone healing after fracture

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Normal bone healing after fracture of distal radius

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Incidence of fracture types

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Forearm fractures are by far the most common type of fracture during childhood. Vertebral compression fractures are distinctly uncommon in children, however, and should always be a cause for concern and additional evaluation.

Children with one or two traumatic fractures are unlikely to have an identifiable disorder and do not routinely require further evaluation. Obtaining a detailed history about the circumstances surrounding a fracture is important in determining the level of concern.

Multiple fractures, atypical fractures such as vertebral compression fractures, low-trauma fractures and a family history of metabolic bone disease are all red flags that should prompt further investigation.

Children with inflammatory bowel disease, celiac disease, chronic glucocorticoid exposure, neuromuscular disorders and others warrant special attention to optimize bone health, since they are at increased risk of low bone density.

A family history of frequent fractures should prompt consideration of inherited conditions, such as osteogenesis imperfecta.

Unexplained fractures, especially in infants, mandate consideration of nonaccidental trauma if an underlying bone disorder is not clearly identified. Poor fracture healing also should raise suspicion of an underlying bone disease. Most fractures in children show radiographic evidence of callus formation by three to six weeks. By eight to 12 weeks, most fractures are united radiographically and no longer require any form of external immobilization.

Evaluation

A basic laboratory evaluation includes such tests as serum calcium, phosphorus, creatinine, parathyroid hormone, 25-hydroxyvitamin D and urine calcium determination.

The serum concentration of 25-hydroxyvitamin D is the best test to determine whether adequate vitamin D stores are present. The serum concentration of the active metabolite of vitamin D (1,25-dihydroxyvitamin D) can be variable in children with nutritional vitamin D deficiency (low concentration of 25-hydroxyvitamin D) and is usually not helpful in determining vitamin D status.

Growing children have a markedly greater serum alkaline phosphatase concentration than do adults, and an appropriate reference range for age and sex should be used. Alkaline phosphatase level will usually be elevated in the context of a recently sustained, healing fracture. Clinical findings supporting a secondary cause of poor bone health also should guide the evaluation.

Dual energy X-ray absorptiometry (DXA) is a widely available technique for determining bone density. Children with frequent, low-trauma or atypical fractures are good candidates for bone density measurement. Children with disorders associated with low bone density, such as inflammatory bowel disease, also may benefit from bone density determination. DXA measurements in children should be performed in centers with experience obtaining and interpreting the scan.

Prevention

Adequate intake of calcium and vitamin D is the foundation of any treatment program to promote bone health. The American Academy of Pediatrics currently recommends that all children receive 400 IU of vitamin D daily, which can be obtained through the diet (mainly milk), supplementation or both. The optimal amount of vitamin D intake or serum vitamin D concentration for children has not yet been clearly defined. Avoiding excessive caffeine and soda intake also should be advised.

Bisphosphonates may be beneficial in select children with low bone density and fractures. They are not approved by the Food and Drug Administration for use in children and should only be given under the supervision of a clinician experienced with their use in children.

Conditions associated with low bone density or fractures in children

Points to remember

• Approximately one-third of children will sustain a fracture by the age of 18 years. Most of these children do not have an underlying metabolic bone disorder that requires evaluation and treatment.
• Multiple fractures, unexplained fractures (especially in infants), atypical fractures (such as vertebral compression fractures), low-trauma fractures and a family history of metabolic bone disease are all red flags that should prompt further investigation.