A novel non-invasive electromagnetic extendable intercalary endoprosthesis: a proof-of-concept study

Area of Science:

• Biomedical Engineering
• Orthopedic Oncology
• Pediatric Orthopedics

Background:

• Primary malignant bone tumors in children often necessitate resection of the femur or tibia, including the physis.
• This surgical intervention frequently leads to significant limb length discrepancy (LLD) at skeletal maturity.
• Existing extendable prostheses primarily focus on joint reconstruction, with a lack of reported analysis on intercalary non-invasive options.

Purpose of the Study:

• To design and evaluate a novel non-invasive electromagnetic extendable intercalary endoprosthesis.
• To assess the feasibility and reliability of this new device for addressing LLD in pediatric bone tumor patients.

Main Methods:

• Conducted in vitro mechanical experiments to assess prosthetic performance.
• Performed in vivo animal experiments to evaluate the extension process and device safety.

Main Results:

• In vitro tests confirmed consistent prosthetic extension at a rate of 4.4 mm per 10 minutes.
• The prosthesis achieved an average maximum extension force of 1306N during elongation.
• In vivo animal studies demonstrated a smooth, non-invasive extension process with the animal remaining comfortable.

Conclusions:

• In vitro and in vivo animal studies provide initial evidence supporting the extension reliability of the novel endoprosthesis.
• These findings lay the groundwork for future large-scale validation experiments.
• The developed device shows promise as a non-invasive solution for intercalary bone defects causing LLD.