低リン血症性ビタミンD抵抗性くる病に対する創外固定を用いた矯正骨切り術

Osteotomy and External Fixation for the Correction of Lower Limb in Vitamin D Resistant Hypophosphataemic Rickets

　抄録：われわれは，著明なO脚変形を来した，低リン血症性ビタミンD抵抗性くる病の2例4肢を経験し，創外固定を用いた矯正骨切り術にて良好な経過を得ている．症例1は12歳，女性．12歳時にけい骨近位にて20°外反，30°外旋矯正し，また，14歳時に両大腿骨に対し，20°外反矯正手術を施行し，Orthofix創外固定器にて固定した．症例2は20歳，男性．20歳時に両下腿骨をけい骨近位にて右側25°外反，45°外旋，左側20°外反，45°外旋矯正し，イリザロフ創外固定器にて固定した．2症例とも経過は良好で，歩容は著明に改善した．本症における下肢変形は，多方向性であり変形角度も大きい．矯正骨切りとプレート固定は困難が予想される．創外固定器は，高度な変形矯正にも使用しやすく，微調整も可能で骨癒合にも有利と思われた．また，内科的コントロールの困難な症例は骨癒合にも不利で，慎重な配慮が必要である．

　We treated two patients with hypophosphataemic rickets and severe bowlegs. External fixation was used for corrective osteotomy in 2 femora and 4 tibiae-fibulae. In the girl in case 1 tibial ostetomy (20 degree valgus and 30 degree external rotation) was performed at 12 years of age and femoral osteotomy (20 degree valgus) at 14 years of age. In the man in case 2 tibial ostetomy (20-25 degree valgus and 45 degree external rotation) was performed at 20 years of age. The outcome of surgery was favorable in both cases, and the patient's walking ability improved. The femoral and tibial deformities in hypophosphataemic rickets are in three planes, and have rotation. Correction of these multidirectional deformities by wedge osteotomies and plating would be difficult. The external fixator allows accurate correction of severe multiplanar deformities and is useful because it is easy to adjust. And adequate medical control of rickets is necessary for bone healing after surgery.