Purpose: A cohort measurement of tibio-femoral angle (TFA) is more meaningful and reliable than a cross-sectional survey in investigating TFA pattern of development. This study reports the pattern of knee angle development in a cohort of normal Nigerian children during the first 2 years of life.

Relevance: Physiotherapists are frequently called on to evaluate children for excessive bowing and age-reference values usually derived from investigations of TFA developmental patterns in children are important in guiding them in such evaluations.

Participants: A total of 152 healthy infants (71 males and 81 females) without any obvious congenital deformity (such as congenital hip dislocation, club foot, calcanio-valgus, pes planovalgus, pes planus) were recruited at birth or within 3 weeks of life from 3 infant welfare clinics in Sagamu town using a consecutive sampling technique.

Methods: Clinical methods were used to assess the knee angle development.TFA was measured using a universal goniometer. Inter-Condylar Distance (ICD) and Inter Malleolar Distance (IMD) were measured using a non-elastic tape measure. Measurements were taken in supine and monthly from ≤3 weeks to 2 years of life.

Analysis: Statistical package for social sciences (SPSS) version 15 was used to analyze the data using descriptive statistics of means, standard deviations, graphs and charts. Pearson’s correlation was used to determine the relationship between the TFA and the ICD/IMD while the t-test was used to assess the TFA differences between genders. 

Results: The developmental pattern of tibio-femoral angle is extreme varus at birth with values ranging from 5⁰ to 25⁰. The mean varus angle at birth (13.2±3.7⁰) decreased to reach the lowest value (5.6±0.7⁰) at nine months and then rose slightly to (6.9±1.2⁰) at 11 months. It fell steeply thereafter to 0.3±2.1⁰ at 18 months. By 19 months the children have changed to valgus presentation. The mean valgus angle rose steadily from -2.4±2.5⁰ at 19 months to -6.9±1.1⁰ at 24 months. ICD and IMD showed a similar course of development from extreme varus at birth (2.5±0.7cm) to neutral (0cm) at 15months, after which it changed to valgus presentation and then rose steadily.

Conclusions: The chronological development of TFA in Nigerian infants is maximal varus at birth, neutral (0⁰) at 18 months and valgus at 19 months of age.

Implications: The age-reference values herewith generated may serve as a useful guide in evaluating lower limb alignment in Nigerian children, age 0-24 months.

Keywords: Tibiofemoral angle; developmental pattern; Nigerian children