Growth in pediatric orthopaedics

Growth analysis should be dynamic and repeated at each clinic visit when indicated. Before any treatment decision, various growth parameters must be considered: growth velocity of standing height, sitting height, lower limbs and growth remaining of the different segments. Chronologic age must be compared with bone age and bone age must be reviewed in light of Tanner signs. One can define a "pubertal age," a synthesis of the clinical and radiologic ages (12,13,17). Bone age is the most impalpable and the most indiscernible parameter. In spite of its imperfection, use of bone age is inescapable. Charts and diagrams are only templates. They do not by themselves define a true age. They define trends and outline the evolution of growth. They should be taken for what they are - a convenient means to map the route to skeletal maturity. Percentages provide an extremely valuable and objective tool for evaluating residual growth, particularly with respect to the proportions between the length of various limb segments and between the limbs and the trunk. However diverse the ethnic origins and even though stature has increased in succeeding generations over the centuries, boys of all generations and ethnic backgrounds have approximately 14% of outstanding growth in standing height and 10% of length of the femur and tibia remaining at the beginning of puberty (3,12,17). The percentages, proportions, and ratios are stable. The humerus makes up about 20% of sitting height and 38% of standing height (17). Whatever the race, the lower limbs double in length at age 2 years, and there remains 50% of growth in the lower limbs at the age of 4 years (12). Despite the diversity of races, velocity of the standing height always has the same pattern. It is extremely rapid during intrauterine life, rapid during the first 5 years after birth, slows after 5 years of age, and followed by acceleration at puberty. All the changes are gradual. Puberty is a short period of approximately 2 years with rapid growth changes. The milestones that mark the path during this period must be noted and understood by the orthopaedic surgeon. The best way to understand growth is to follow its patterns. One must embrace its rhythms and its cadences in order to control it. This is best done by perceptive, repetitive collection of measurements. The more accurate and frequent the data, the more sensitive and precise is the treatment. Rigorous analysis and flexibility in the interpretations are the keys for success.