Femoral Magnetic Lengthening After Distal Femur Endoprosthetic Reconstruction in a Pediatric Patient: A Case Report.

CASE: A 10-year-old boy with osteosarcoma of the left distal femur underwent resection with compressive osseointegration endoprosthetic reconstruction, gradually resulting in a 4.5-cm leg-length difference with significant predicted progression. Two years after resection, he underwent right distal femur and proximal tibia epiphysiodesis and placement of a left femoral magnetic lengthening nail. At 2 years after lengthening and skeletal maturity, the patient has symmetric limb lengths, no pain, and returned to sports. CONCLUSION: A magnetic lengthening nail with contralateral epiphysiodesis is a viable option for correcting limb-length discrepancy after distal femur endoprosthetic reconstruction in a pediatric patient.