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DOI: 10.1055/s-0040-1714939
Biomechanical Comparison of External Fixation and Bilateral Plating for Stabilization of a Canine Cadaveric Distal Metaphyseal Humeral Fracture Gap Model
Publication History
Publication Date:
20 July 2020 (online)
Introduction: Successful stabilization of comminuted supracondylar humeral fractures is challenging, and biomechanical studies are scarce. This study compares bilateral plate fixation (BI-PLATE) and linear external fixator with an intramedullary pin tie-in fixation (EX-FIX) techniques in a cadaveric gap model. We hypothesized that the BI-PLATE construct would outperform the EX-FIX construct in both cyclic and load-to-failure axial compression testing.
Materials and Methods: A 2-cm ostectomy was performed on 10 pairs of canine cadaveric humeri proximal to the supratrochlear foramen. Stabilization was with BI-PLATE (n = 10) or EX-FIX (n = 10). Cyclic testing was performed by applying a 200 N load at 2 Hz for 63,000 cycles. Axial compressive load to failure testing followed. Data analyzed included dynamic stiffness, stiffness and yield load.
Results: No constructs failed during cyclic testing or lost stiffness over time. Mean dynamic stiffness was greater for BI-PLATE (277 N/mm) compared with EX-FIX (230 N/mm; p = 0.006). Mean stiffness of BI-PLATE in load-to-failure testing was not different than EX-FIX (p = 0.160). Yield load of BI-PLATE (846 N) was higher than EX-FIX (501 N; p = 0.002).
Discussion/Conclusion: Both BI-PLATE and EX-FIX survived cyclic testing with no change in dynamic stiffness. BI-PLATE was stronger than EX-FIX in load-to-failure testing, which may make this construct preferable when prolonged healing or poor patient compliance is anticipated. Results indicate that either method may be appropriate for fixation of comminuted supracondylar humeral fractures.
Acknowledgment: This study was partially funded by a MSU House Officer Clinical Research Grant. Reduced-cost implants were provided by IMEX, VOI and Orthomed.