Profile of patients with Blount’s disease at an Academic Hospital

Abstract

Introduction Despite an increased incidence of Blount’s disease in South Africa, the aetiology is unknown with a historical predisposition attributable to an early walking age, large stature, obesity, Black African race and genetics. The aim of this study is to explore the profile of patients with Blount’s disease seen at an Academic Hospital. Materials and Methods This is a retrospective case series with an evaluation of hospital and outpatient records (data sheets) of children diagnosed with Blount’s disease (Infantile, Juvenile and Adolescent Groups) from 01 January 2003 to 31 December 2016. Demographic information including age when the deformity was first noticed, age at presentation, gender, race, weight, height, milestones, bilateral involvement and family history were documented. Results Data was available for 108 patients with a total of 172 involved limbs. In this series all patients were of Black African race. There were 12 documented cases with a family history of bow legs (seven in the Infantile Group, five in the Juvenile Group and zero in the Adolescent Group). The developmental milestones of patients within all three groups were within normal limits and in particular were not early. The majority of the patients in the Infantile and Juvenile Groups were female whereas the Adolescent Group had a male predominance. There was a similar occurrence of bilateral involvement in both the Infantile Group (64%) and the late-onset group (56%). The median BMI for patients in the Infantile Group was lower than that for children in the Juvenile and Adolescent Groups (19.49, 28.5 and 33.4 respectively). A greater proportion of male patients were classified as obese compared to female patients (82% versus 50%) and there was no significant difference with the BMI of patients with unilateral and bilateral deformity. Conclusion In this population, this study confirms a heritable component in Blount’s disease (20%). Early-onset walking age was not a risk factor for Infantile Blount’s disease. There was a iv female preponderance in the Infantile and Juvenile Groups but a male preponderance in the Adolescent group. The BMI increased with increasing age. A greater proportion of male patients were classified as obese compared to female patients for reasons undetermined (82% versus 50%). No risk factors were found for unilateral involvement. This paper has helped to elucidate the above mentioned facts in this population of patients with Blount’s disease.