| 저자 |
Ju Young Cho1*, Jong Min Kim1, Donghwi Park1, Byung Joo Lee1, Kwang Jae Yu1, Hyunseok Moon1, Sungwon Park1, ZeeIhn Lee1† |
Introduction
In hypophosphatemic rickets, softening and weakening of the bone causes bending deformities in long bone (e.g. genu varum or genu valgum) in response to weight-bearing. And affected child often walks with waddling gait due to coxa vara and/or in-toeing gait secondary to internal tibial torsion.
Internal tibial torsion is a variation of normal anatomy and is caused partially by intrauterine position, sleeping in the prone position after birth, and sitting on the feet. It is the most common cause of in-toeing gait in children between the ages of 2-4 years. Examining a child with internal tibial torsion with the patella straight, there will be medial rotation of the feet. Internal tibial torsion gradually resolves on its own by the time the child reaches eight years of age.
Despite adequate medical treatment, some patients with hypophosphatemic rickets are left with residual skeletal deformities and these skeletal deformities may require surgical correction when growth has ceased.
Therefore, we tried to treat internal tibial torsion in patient with hypophosphatemic rickets using orthotic device (e.g. tibia counter-rotator (TCR) that can correct the tibial torsion by gradually adjusting the angle of shoe rotation) before invasive surgical treatment.
Case
The patient is 12-year-old female who diagnosed as hypophosphatemic rickets at the age of 2. After diagnosis, treatment was started with supplementation of phophate as Joulie`s solution and oral calcitriol was also given. The dose of the drug was adjusted based on regular blood tests and she is still taking medication continuously.
At the age of 10, the patient visited our clinic and complained about in-toeing gait. On physical examination, right genu varum, left genu valgum and in-toeing gait pattern were seen. TMA measured by gravity goniometer was -34 degree on the right side and -17 degree on the left side. On low extremity CT, Femoral anteversion angle was 7.2 degree on the right side and 12 degree on the left side. And tibial torsion angle was -8 degree on the right and -3 on the left side. Then, we applied the right TCR and biomechanic foot orthosis (BFO). 6 months after applying orthosis, we found that TMA was improved with -14 degree on the right side and -1 degree on the left. And 18 months after the treatment, TMA was measured at 6 degree on the right and 12 degree on the left and in-toeing gait pattern was significantly improved as well.
Conclusion
There is controversy about the effectiveness of orthotic devices in treating patients with in-toeing gait caused by internal tibial torsion, but patients with rickets, whose skeletal deformities is only treated by invasive treatments such as surgery, could try the TCR for in-toeing gait before considering surgery.
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