Windswept lower limb deformities in patients with hypophosphataemic rickets

Kaissi Al,F Grill,R Ganger,K Klaushofer,S Farr

doi:10.4414/smw.2013.13904

Abstract

X-linked hypophosphataemic rickets is an X-linked dominant disorder that is secondary to renal phosphate-wasting. Genu varum and/or genu valgum have been described as the most common deformities in patients with hypophosphataemic rickets. Windswept deformity, which is valgus deformity in one knee and varus deformity in the other, was the most common deformity encountered in our department. We collected seven patients who had phenotypic and genotypic features consistent with the diagnosis of X-linked hypophosphataemic rickets. All presented with windswept lower limb deformity. We discuss the phenotypic and genotypic correlation, and the surgical procedures applied. Surgical interventions were scheduled to correct the triad of appearance, function and biomechanics. Re-alignment orthopaedic measures were applied to correct and to restore normal growth and development in these children. Post-operative measurements showed dramatic improvements in balance and gait. The most common deformity seen in patients with hypophosphataemic rickets is gradual anetrolateral bowing of the femur combined with tibia vara. Windswept lower limb deformity was the most common angular deformity in our patients with hypophosphataemic rickets. Baseline skeletal surveys and genotypic characterisation were subject to close scrutiny and assessment, with the aim of proper diagnosis and treatment. Nevertheless, recurrence of deformity is a common sequel and younger patients have a higher risk for recurrence.

Highlights

Disturbances of skeletal growth presenting at birth or developing in childhood produce a bewildering array of clinical, radiological and pathological syndromes
Windswept deformity, which is valgus deformity in one knee and varus deformity in the other, was the most common deformity encountered in our department
The most common deformity seen in patients with hypophosphataemic rickets is gradual anetrolateral bowing of the femur combined with tibia vara

Summary

Introduction

Disturbances of skeletal growth presenting at birth or developing in childhood produce a bewildering array of clinical, radiological and pathological syndromes. The term “windswept deformity” describes the appearance of an abnormal valgus deformity in one knee in association with varus in the other. It is commonly seen in young children in certain parts of Africa, and its development is secondary to metabolic bone diseases. Metabolic bone diseases frequently result in skeletal deformities, especially in the legs, owing to physeal disturbances or defective mineralisation in children before puberty. Among these disorders, hypophosphataemic rickets, hypophosphatasia and renal osteodystrophy are the most frequent, but, other syndromic entities have been reported [7, 8]. Identifying patients with unusual skeletal deformities is of value because it illustrates that the more severely involved the locomotor system is, the greater the likelihood of having a syndromic complex

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