Blount's disease in a pair of identical twins

Blount disease and familial inheritance in Ghana, area cross-sectional study

Objective

The objective of this study is to study familial inheritance for Blount disease to create better understanding of the aetiology of Blount disease.

Methods

After reviewing patient files and conventional roentgenologic imaging, 139 patients with Blount disease were included in this cross-sectional study, of which 102 patients were interviewed. During the interviews, patient characteristics and family history were collected. Blood samples were taken from five patients and three families and a whole exome sequencing was performed.

Results

Although patients came from all over the country, 90% of the patients belonged to the Akan tribe. A positive family history was found in 63 families (62%), of which, almost two-third had a positive family history in a first-degree family member. In most of the cases (64%), the varus legs resolved over time. In 9%, severe bowing remained 'just like the patient'. The results of the whole exome sequencing did not show a genetic predisposition.

Conclusion

This study describes a large group of Blount patients. Because of the high numbers of positive family history and the centralisation of patients in the Akan region, a familial predisposition is suggested. Further genetic research is essential for better understanding of the possible multifactorial aetiology in Blount disease.

Blount's disease: magnetic resonance imaging

To evaluate the information obtained by magnetic resonance (MR) imaging, the radiographic and MR investigations of nine patients treated for idiopathic tibia vara were reviewed in retrospect. There were six unilateral and three bilateral cases (12 tibiae). Initial radiographs of each patient were assigned a stage according to Catonné's classification. MR imaging was performed with a 0.5- or 1.5-T apparatus. Bony epiphyses were poorly developed in all cases. The cartilaginous component of the epiphyses compensated partially (6/12 cases) or completely (6/12 cases) for the collapse of the physes. In two cases an abnormal area was found between the medial meniscus and the cartilaginous portion of the epiphysis. An abnormally large medial meniscus was noted in four cases; an abnormal signal in the medial meniscus was seen in two cases. MR imaging has several advantages over plain film: it uses no ionizing radiation, it shows the shape of the ossified and cartilaginous epiphysis, and it demonstrates meniscal and physeal abnormalities. MR imaging may influence the choice of treatment.