Knee Angles and Rickets in Nigerian Children

Abstract

Knee angles of 2,036 normal Nigerian children up to 12 years old were measured directly or from photographs. The knees were bowed (varus) in the first 6 months. At 21 to 23 months, the distribution of angles became strongly bimodal: about half were varus and half were valgus (knock-kneed), with few in between. After this they were all valgus, with few exceptions. Hence, the change from varus to valgus in individual infants must be sudden (a few weeks), although the changeover of the whole population appears smooth and gradual. They became maximally and uniformly knock-kneed (-7.1 degrees +/- 1.4 degrees) between 3 and 3.5 years, with little change thereafter. On the other hand, 120 patients with rickets discovered during screening had large knee angles, in either sense, with a bimodal distribution and frequency maxima at +10 degrees (varus) and -12 degrees (valgus). Varus knee is uncommon after 2 years. Large knee angles between 2 and 5 years suggest rickets.

Clinical tibiofemoral angle in south Indian children

“…This was comparable with the maximal valgus values described by Oginni et al 11 in Nigerian children (-7.1° ( sd 1.4)) and by Yoo et al 12 in Korean children (7.8°). However, Chinese, Turkish and Saudi children had higher peak valgus values of 8°, 9.6° to 9.8° and 9.46° ( sd 0.85), respectively.…”

“…Thus reversal of physiological varus in our population has already occurred before the age of two years. This observation was comparable with the first published study by Salenius and Vankka 2 in Caucasian children and also Cheng et al, 3 Heath and Staheli, 4 Oginni et al, 11 Saini et al 8 and Rahman and Badahdah 13 in Chinese, white, Nigerian, Indian and Saudi children, respectively. We found no children with varus at the two- to three-year transition period.…”

“…In the largest study by Cheng et al 3 in 2630 Chinese children, a maximum IMD of 2.8 cm was observed at the age of three years. Oginni et al 11 reported maximal and uniform knock-knees (-7.1° ( sd 1.4)) between three and 3.5 years of age in Nigerian children, while Rahman and Badahdah 13 reported maximum mean valgus of 9.46° ( sd 0.85) at three to four years of age in Saudi children.…”

“…However, these ranges have been shown to differ with respect to age, time to transition from infantile varus to valgus, peak valgus and gender variation in children of different ethnic groups. 3-5,8,11-14 …”

“…2-4,11,13 Salenius and Vankka 2 recorded peak valgus angulation in the Caucasians at two to three years of age, and Heath and Staheli 4 reported greatest mean knock-knee of 8° at a mean age of four years. In the largest study by Cheng et al 3 in 2630 Chinese children, a maximum IMD of 2.8 cm was observed at the age of three years.…”