LAUSR

Abstract Rationale: Hypophosphatemic rickets (HR) is a rare hereditary disease characterized by hypophosphatemia, defects in bone mineralization, and rickets, and surgical intervention is warranted for the patient of severe skeletal deformity. Patient concerns: Here we report a case of an 11-year-old boy who presented with severe varus deformities of the bilateral lower extremities and was associated with uncoordinated gait with multiple unintentional falls onto ground resulting in fractures of lower extremities. Diagnoses: He was diagnosed as HR caused by genetic mutations in the phosphate-regulating endopeptidase homologue. Based on his family history and laboratory tests, including high serum alkaline phosphatase, high urinary phosphorus, hypophosphatemia, and normal serum calcium level, the patient was diagnosed with this disorder. Interventions: Rotational and translational osteotomy was performed to redress the severe varus deformity and readjust the malalignment of the lower extremity. Outcomes: Right after the surgery, the alignment in the left lower extremity was readjusted, and his appearance seemed normal. Combined with rehabilitation and pharmacological intervention, including oral intake of phosphate and alphacalcidol, the bone healed uneventfully. After the second surgery of a similar procedure on the right femur, the patient was able to walk almost like a normal teenager. Lessons: This case proposed a novel technique to treat severe varus or valgus deformity of the lower extremity. HR is a rare disease, and it is important to stress its recognition to avoid delay of diagnosis and surgical intervention if necessary.