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Acrylic Resin Molding Based Head Fixation Technique in Rodents

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Difficulty in locking head screw removal.

Kenji Fujita¹, Hidetoshi Yasutake², Takeshi Horii²

¹Department of Orthopaedic Surgery, Ishikawa Prefectural Central Hospital, 2-1 Kuratsukihigashi, Kanazawa, Ishikawa 920-8530, Japan; Department of Orthopaedic Surgery, Graduate School of Medical Science, Kanazawa University, 13-1 Takaramachi, Kanazawa, Ishikawa 920-8641, Japan.

Journal of Orthopaedic Science : Official Journal of the Japanese Orthopaedic Association

|December 4, 2013

Summary

This summary is machine-generated.

Difficulty removing locking head screws (LHSs) is linked to 3.5 mm diameter screws, younger patient age, and longer fixation times. Surgeons should use appropriate instruments and training for these cases.

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Area of Science:

Orthopedic surgery
Biomaterials science
Surgical instrumentation

Background:

Locking plates are crucial for bone fracture stabilization using locking head screws (LHSs).
Difficult removal of LHSs is a known complication, potentially prolonging surgery.
Identifying incidence and risk factors for difficult LHS removal is essential for improving surgical outcomes.

Purpose of the Study:

To determine the incidence of difficult locking head screw removal.
To identify risk factors associated with difficult removal of 3.5 mm diameter LHSs.
To provide recommendations for mitigating removal difficulties.

Main Methods:

Retrospective analysis of 482 LHS removals from 83 locking plates over 5.5 years.
Categorization of LHSs by diameter (2.4-2.7 mm, 3.5 mm, 5.0 mm) to assess removal difficulty incidence.
Risk factor analysis for 3.5 mm diameter LHSs, comparing difficult vs. easy removal groups based on age, sex, time to removal, and screw position.

Main Results:

No removal difficulty was observed for 2.4-2.7 mm and 5.0 mm diameter LHSs.
A 4.9% incidence of removal difficulty was noted for 3.5 mm diameter LHSs.
Younger age (mean 32.1 vs 45.6 years) and longer time between insertion and removal (mean 529.2 vs 389.2 days) were significant risk factors for difficult 3.5 mm LHS removal.

Conclusions:

The 3.5 mm diameter locking head screw is a necessary condition for removal difficulty.
Younger patient age and extended periods between internal fixation and removal increase the risk of difficult LHS removal.
Adequate surgical instrumentation and specialized training are recommended for removing 3.5 mm diameter LHSs.