While there is no exact age for the culmination of bone maturity, modern research suggests a range of between 15-17 years for bone maturity in boys and 14-16 years for girls.
In clinical practice, a bone age that is 20 percent below or above the chronological age is considered abnormal.
The bone age will determine the maturity of your child's bones, compared to your child's chronological (actual or “birthday”) age. A child with GHD may have a bone age that is much less than his/her chronological age.
What's a Bone Age Study? A bone age study helps doctors estimate the maturity of a child's skeletal system. They do this by taking a single X-ray of the left wrist, hand, and fingers. The bones on the X-ray image are compared with X-ray images in a standard atlas of bone development.
To appreciate the clinical relevance of a more accurate bone age assessment, we note that the SD of bone age of healthy subjects at a fixed age is of the order of 1.0 y (above the age of 7 y), i.e. the natural variance is 1.0 y2. The typical manual rater accuracy is 0.58 y, which corresponds to a variance of 0.34 y2.
“Any child with bone age more than 2 years advanced or delayed, or whose growth pattern deviates from their genetic potential should bereferred to endocrinology for assessment,” she noted.
The most accurate method of height prediction comes from using a child's "bone age," determined by an X-ray of the hand, but there are several methods you can use at home to get an idea of how tall your child will eventually become.
Therefore, chronological age differs from bone age, so the two indexes need to be distinguished: chronological age is defined as the age in years between birth and the evaluation of a subject; bone age is defined by the age expressed in years that corresponds to the level of maturation of bones.
Typically, girls' growth plates close when they're about 14-15 years old on average. Boys' growth plates close by around the time they turn 16-17 on average. This occurs earlier in some individuals and later in others. Also, different bones' growth plates close at different times.
A T score of -1 to +1 is considered normal bone density. A T score of -1 to -2.5 indicates osteopenia (low bone density). A T score of -2.5 or lower is bone density low enough to be categorized as osteoporosis.
Large differences between a person's bone age and their chronological age may indicate a growth disorder. For example, a patient's bone age may be less than their chronological age suggesting a delay in growth as may be caused by a growth hormone deficiency.
Pubertal development
If the bone age and pubertal stage are delayed, the child would be expected to have a later puberty than average and catch up in height by growing longer than average. However, there are several caveats to the diagnosis of constitutional delay of growth.
Overview. Progeria (pro-JEER-e-uh), also known as Hutchinson-Gilford progeria syndrome, is an extremely rare, progressive genetic disorder.
There are several reasons for using left hand and wrist radiographs for bone age assessment rather than right hand and wrist radiographs. One reason is that most people are right-handed, and therefore, the right hand is more likely to be injured than the left hand (1).
Bone age was also similar to chronological age for children with height under the 20th percentile, but was advanced for taller children (Table 2, Figure 4).
Advanced bone age was defined as patients who had a difference >2 SD between bone and chronological age. Children were divided into a normal or advanced bone age group. We compared the two groups and analyzed the prevalence of advanced bone age according to factors associated with childhood obesity.
Variations of Normal Growth Patterns
They usually have a delayed "bone age," which means that their skeletal maturation is younger than their age in years. (Bone age is measured by taking an X-ray of the hand and wrist and comparing it with standard X-ray findings seen in kids the same age.)
Short stature is defined as a condition in which an individual's height is in the 3rd percentile for the mean height of a given age, sex, and population group.
The Khamis-Roche method is considered to be one of the more accurate height prediction methods that do not require the measurement of bone age. It is based on the child's stature, weight, and the average stature of the two parents. The first calculator above is mainly based on this method.
Skeletal maturation can be delayed by reducing the exposure to estrogens, either by halting pubertal development through administering a GnRH analogue (GnRHa), or by blocking the conversion of androgens to estrogens through an aromatase inhibitor (AI).