PMC6120294_01
Radiographs of the lower extremities at the time of the first lengthening. (a) An anteroposterior standing radiograph of the lower extremities at seven years of age showing LLD of nearly 10 cm with the right foot placed on a block. (b) An anteroposterior supine radiograph of the lower extremities at the end of the lengthening period of the first lengthening demonstrating 83 mm and 37 mm of lengthening in the femur and tibia, respectively. (c) An anteroposterior radiograph of the right femur showing regenerate fracture at the site of the lengthened callus.
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LLD increased with time and reached nearly 10 cm at seven years of age (Figure 1(a)). As a result, the lengthening period/amount of lengthening of the femur and tibia were 90 days/83 mm and 163 days/37 mm, respectively, and an overall leg length was 7 mm longer in the affected limb at the end of the lengthening period (Figure 1(b)). Regenerate fracture of the femur, however, occurred due to minor trauma three days after the pin removal (Figure 1(c)).
Radiographs of the lower extremities at the time of the second lengthening. (a) An anteroposterior supine radiograph of the lower extremities at eleven years of age before the second lengthening revealing LLD of 11 cm. (b) A radiograph of the right femur just after the femoral osteotomy demonstrating acute correction of an anterolateral bowing deformity. (c, d) Radiographs of the right femur before (c) and after (d) the chipping surgery.
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After the first lengthening procedure, LLD gradually increased again and reached 11 cm at eleven years of age (Figure 2(a)), when the flexion angle of the right knee decreased to 30 degrees. After correction of the angular deformity, the osteotomy site was compressed (Figure 2(b)). Since the callus was poorly consolidated in the femur (Figure 2(c)), a modified "chipping and lengthening technique" was performed to enhance bone regeneration at nine months postoperatively (Figure 2(d)).
Current radiograph and view of the lower extremities. (a) An anteroposterior supine radiograph of the lower extremities at 17 years of age showing an anterolateral bowing of the right femur and a medial bowing of the right tibia. (b) A postoperative view of the right lower extremity showing atrophic skin surfaces on the posteromedial aspect of the thigh and the medial aspect of the lower leg, where brown pigmented cutaneous lesions were observed at the first presentation.
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Currently, two or three years have passed since the final removal of the femoral or tibial pins, respectively, and 38 mm of LLD is left with acceptable lower limb alignment (Figure 3).