Effect of Body Mass Index (BMI) On Degree of Angular Knee Deformity in Children with Blount\'s Disease.

Abstract

The aetiology of Blount\'s disease remains unknown, but it is generally agreed that weight bearing plays a role in the
pathogenesis of knee deformity in these patients. Our aim was to analyze the effect of Body Mass Index (BMI) on the degree of angular knee deformity in children with clinical and radiological features of Blount\'s disease.
This was a prospective analysis which involved 20 patients (38 knees) with clinical and radiological evidence of Blount\'s disease. Forty controls (80 knees) without clinical evidence of knee pathology were recruited for comparison. The Body Mass Index (BMI) was determined for each patient using the Johan Van Hespen BMI calculator. The degree of angular deformity in patients with Blount\'s disease was determined by measuring the
intercondylar distance (ICD). Results obtained were subjected to statistical analysis with significance level set at P< 0.05. The mean BMI in patients with Blount\'s disease was 19.6±6.6. This was higher than the mean BMI (16.91 ± 2.82) for patients in the control group (P = 0.0468). The mean ICD for patients with Blount\'s disease was 15.7±9.07cm. We however found no correlation between BMI and degree of deformity in patients with Blount\'s disease. Patients with Blount\'s disease have significantly higher BMIs than normal patients but this alone does not account for the severity of deformity in these patients.


Keywords: Blount\'s Disease, Body Mass Index, Angular knee deformity

Nigeria Journal of Orthopaedics and Trauma Vol. 7 (2) 2008: pp. 76-78