Windswept lower limb deformities in patients with hypophosphataemic rickets

Swiss Med Wkly. 2013 Dec 6;143:w13904. doi: 10.4414/smw.2013.13904. eCollection 2013.

Abstract

Background: 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.

Patients and methods: 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.

Results: 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.

Conclusion: 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.

MeSH terms

  • Abnormalities, Multiple*
  • Adolescent
  • Child
  • Familial Hypophosphatemic Rickets / complications
  • Familial Hypophosphatemic Rickets / genetics
  • Familial Hypophosphatemic Rickets / pathology*
  • Femur / surgery*
  • Genu Valgum / etiology
  • Genu Valgum / surgery*
  • Genu Varum / etiology
  • Genu Varum / surgery*
  • Humans
  • Male
  • Osteotomy / methods*
  • PHEX Phosphate Regulating Neutral Endopeptidase / genetics
  • Phenotype
  • Tibia / surgery*

Substances

  • PHEX Phosphate Regulating Neutral Endopeptidase
  • PHEX protein, human