Relevance. Relapses of deformities of the lower extremities after their surgical correction in patients with hypophosphatemic rickets reach 95%, which requires improved approaches to the treatment of this pathology. The aim of the study was to study the efficacy and safety of staged surgical treatment, including osteotomy, sequential transosseous and intraosseous blocking osteosynthesis-reinforcement, in a patient with completed growth, suffering from X-linked dominant form of hypophosphatemic rickets. Materials and methods. A patient with completed growth with an X-linked dominant form of hypophosphatemic rickets at the age of 21–28 years underwent 11 operations on the lower extremities due to their pronounced multiplanar multiapical deformities, segment length inequality against the background of osteomalacia. Simultaneous corrections were made on the femurs using osteotomies and intraosseous blocking osteosynthesis-reinforcement. On the bones of the lower legs, staged corrections were performed using osteotomies, bone autoplasty, sequential transosseous and intraosseous blocking osteosynthesis-reinforcement. Results. The inequality of the lengths of the femurs and lower legs is eliminated. The axes of the lower extremities were corrected to normal. The patient's height has increased by 8 cm. He walks up to 25,000 steps a day without additional support. When observing the patient for 8 years, no relapses of deformities and other complications were noted. Conclusion. Our experience testifies to the high efficiency and safety of staged surgical treatment using osteotomies, transosseous and intraosseous blocking osteosynthesis-reinforcement for the correction of pronounced multiplanar multiapical deformities, inequality in the length of the bones of the lower extremities against the background of osteomalacia in the patient with completed growth, suffering from an X-linked dominant form of hypophosphatemic rickets.