Comparative evaluation of posterior interosseous nerve strain in lateral approach to radial head fixation: a cadaveric study
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Issued Date
2025-01-01
Resource Type
ISSN
10582746
eISSN
15326500
Scopus ID
2-s2.0-105016568827
Pubmed ID
40818605
Journal Title
Journal of Shoulder and Elbow Surgery
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SCOPUS
Bibliographic Citation
Journal of Shoulder and Elbow Surgery (2025)
Suggested Citation
Sangkamard K., Limthongthang R., Laohaprasitiporn P., Vathana T., Monteerarat Y. Comparative evaluation of posterior interosseous nerve strain in lateral approach to radial head fixation: a cadaveric study. Journal of Shoulder and Elbow Surgery (2025). doi:10.1016/j.jse.2025.06.028 Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/112343
Title
Comparative evaluation of posterior interosseous nerve strain in lateral approach to radial head fixation: a cadaveric study
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Abstract
Background: The posterior interosseous nerve (PIN) is at significant risk during proximal radius exposure. This study investigates the risk of PIN traction injury by comparing PIN strain between the Kocher and Kaplan approaches during simulated plate fixation of radial head fractures using upper limb cadaveric models. Methods: Fourteen fresh-frozen upper extremity specimens were dissected with Kaplan (n = 7) and Kocher (n = 7) approaches, and the PIN was exposed at the anterior elbow with a separate incision. A Microminiature Displacement sensor (M-DVRT-9; LORD MicroStrain, Williston, VT) was positioned on the PIN at its origin from the radial nerve and just proximal to the supinator muscle. PIN displacement was recorded, and PIN length (distance between 2 sensors) was measured using a vernier caliper. PIN strain (%) was calculated by dividing the excursion of the PIN by its length. Strains were compared between the Kaplan and Kocher approaches in neutral, supination, and pronation at 90° elbow flexion. Both standard and extensile versions were tested under scenarios with and without lateral ulnar collateral ligament (LUCL) insufficiency, employing a custom K-wire jig to standardize traction forces. Results: The standard and extensile Kaplan approaches exhibited significantly higher strains compared to the Kocher approach. The standard Kaplan approach resulted in median PIN strains of 3.87% in neutral, 4.51% in supination, and 4.41% in pronation—markedly higher than the Kocher approach, which maintained strains below 0.1% in all conditions. Strain values nearly doubled with the extensile Kaplan approach, although the increase was not statistically significant. When LUCL insufficiency was combined with the extensile Kaplan approach, significant variability in PIN strain was observed, with levels ranging from 0.01% to 46.80%. One specimen exhibited particularly high strain values of 39.04% in neutral, 46.80% in supination, and 33.62% in pronation. No significant difference in nerve strain was observed between forearm positions within any approach. Conclusion: The Kaplan approach significantly increases PIN strain during exposure for internal fixation of radial head and neck fractures, thereby highlighting the potential risk of PIN traction injuries. In contrast, the Kocher approach is more effective in minimizing PIN traction injury. Even when utilizing an extensile approach to improve exposure, the strain on the PIN remains minimal. Caution is advised when using the Kaplan approach, particularly in cases of gross elbow instability, as dislocation of the radial head or deficiency of the LUCL can increase the risk of PIN injury from excessive traction.