Staged Reconstruction of Distal Femoral Osteosarcoma in a 10-year-old Girl using a Hybrid Endoprosthesis-Motorised Lengthening Nail Construct: A Case Report.
This case report describes staged limb-salvage reconstruction in a 10-year-old girl with distal femoral osteosarcoma using a hybrid endoprosthesis–motorised lengthening nail, achieving 6 cm of distraction-generated length and a reported 1-cm residual discrepancy with pain-free activity at latest follow-up.
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This case report describes staged limb-salvage reconstruction in a 10-year-old girl with distal femoral osteosarcoma using a hybrid endoprosthesis–motorised lengthening nail, achieving 6 cm of distraction-generated length and a reported 1-cm residual discrepancy with pain-free activity at latest follow-up.
Research significance
The reported case supports feasibility of generating native bone length after pediatric osteosarcoma resection through a temporary hybrid endoprosthesis–motorised nail construct; it remains an inference, requiring larger and longer-term studies, that this strategy could preserve bone stock, reduce repeated prosthetic expansions, and improve future revision options compared with conventional expandable prostheses.
Source abstract
BACKGROUND: Reconstruction of tumour defects in skeletally immature patients poses a particular challenge due to the resection of growing physes and resulting limb-length discrepancies. Expandable prostheses allow outpatient lengthening with fewer surgical revisions, but the limb is lengthened within the prosthesis rather than native bone. CASE DESCRIPTION: A 10-year-old girl with no medical history presented with distal right thigh pain and swelling. Imaging and biopsy confirmed osteosarcoma. She underwent wide local excision and initial endoprosthetic reconstruction, followed by a planned staged exchange to a hybrid endoprosthesis (BioXpand), in which the usual prosthetic stem is replaced by a motorised intramedullary nail (Fitbone), allowing limb lengthening via distraction osteogenesis. The patient began non-invasive lengthening on postoperative day five (approximately 0.96 mm/day), with the rate adjusted weekly based on clinical and radiological parameters. After 12 weeks, 6 cm of length was achieved, and consolidation took a further 6 weeks before full weight-bearing. Finally, the reconstruction was converted into a definitive static prosthesis once the final limb length was achieved. At the latest follow-up, the patient attends school and participates in sports, reports no pain, and is skeletally mature, with a 1-centimetre leg-length difference. CONCLUSION: This case demonstrates the feasibility of a staged approach to the reconstruction of paediatric osteosarcoma by combining the principles of endoprosthetic reconstruction with distraction osteogenesis. A staged strategy enabled oncologic clearance, growth accommodation, and functional preservation. CLINICAL SIGNIFICANCE: Staged BioXpand reconstruction offers a 'bioexpandable' alternative to expandable endoprostheses by restoring length through distraction osteogenesis rather than metal extension. A modular sequence (primary reconstruction, hybrid nail exchange for outpatient lengthening, then definitive static conversion) can equalise limb length while generating bone stock, supporting future revisions.