Half-pin Breakage in Multiplanar External Fixators Used for Pediatric Deformity Correction

Area of Science:

• Orthopedic surgery
• Pediatric orthopedics
• Biomechanical engineering

Background:

• Multiplanar external fixators are crucial for correcting complex pediatric leg deformities.
• Half-pin breakage was observed in four cases using the Orthex hexapod frame.

Purpose of the Study:

• To identify factors contributing to half-pin breakage in pediatric lower extremity deformity correction.
• To compare deformity correction characteristics between the Orthex and Taylor Spatial Frame (TSF) hexapod systems.

Main Methods:

• Retrospective review of pediatric patients treated with Orthex or TSF frames between 2012 and 2022.
• Comparison of frame configuration, fixation methods, correction achieved, and treatment duration.

Main Results:

• Four Orthex frames experienced proximal half-pin breakage; zero TSF frames did.
• Orthex frames were associated with younger patients, more proximal half-pins, nonstandard configurations, and longer treatment times.
• No significant differences were found in length gained, angular correction, or healing index between the two frames.

Conclusions:

• This study is the first to report half-pin breakage with multiplanar frames in pediatric lower extremity deformity correction.
• Pin breakage appears multifactorial, linked to increased complexity in deformity correction and specific frame configurations.
• Differences in patient populations and frame setups between Orthex and TSF groups complicate direct causation attribution.