Mechanical Failures in Magnetic Intramedullary Lengthening Nails.

Area of Science:

• Orthopedic surgery
• Biomedical engineering
• Reconstructive surgery

Background:

• Magnetic intramedullary lengthening nails (MILNs) are increasingly used for limb length discrepancies.
• Assessing mechanical failures and their management is crucial for optimizing treatment outcomes.
• This study analyzes a large single-institution series of MILN mechanical failures.

Purpose of the Study:

• To catalog mechanical failures in magnetic intramedullary lengthening nails (MILNs).
• To assess the rates, types, and management strategies for MILN mechanical failures.
• To identify factors influencing mechanical failure in limb lengthening procedures.

Main Methods:

• Retrospective review of 377 patients (420 limbs) using early (P1) and later (P2) MILN iterations.
• Mechanical failure defined as instrumentation breakage or internal lengthening mechanism failure.
• Radiographic assessment of lengthening, alignment, and complication classification.

Main Results:

• Overall mechanical failure rate of 9.5% (40 nails).
• Failure rates were 11.3% for P1 nails and 9% for P2 nails.
• Most failures (63%) were corrected surgically; nail replacement was common during lengthening and consolidation phases.

Conclusions:

• A 9.5% mechanical failure rate for MILNs was observed, with most cases managed surgically.
• Close monitoring of nail distraction and weight-bearing compliance is essential.
• Careful radiographic assessment is needed for nail extraction to prevent complications.