External fixator-augmented flexible intramedullary nailing of an unstable pediatric femoral shaft fracture model: a biomechanical study
| Autor: | Corey A Burke, Martin J. Morrison, Serkan Inceoglu, Peter J Wilton, Scott C. Nelson |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Male
Models Anatomic External fixator Adolescent External Fixators Femoral Shaft Fracture Bone Nails law.invention Intramedullary rod 03 medical and health sciences 0302 clinical medicine law medicine Humans Orthopedics and Sports Medicine Femur Orthodontics 030222 orthopedics business.industry Stiffness Compression (physics) Biomechanical Phenomena body regions Compressive strength Pediatrics Perinatology and Child Health Fracture (geology) Female medicine.symptom business Femoral Fractures 030217 neurology & neurosurgery |
| Zdroj: | Journal of Pediatric Orthopaedics B. 29:485-489 |
| ISSN: | 1060-152X |
| DOI: | 10.1097/bpb.0000000000000648 |
| Popis: | The objective of this study was to test the compressive strength and torsional stiffness provided by the addition of a two-pin external fixator to an unstable pediatric femoral shaft fracture model after being instrumented with flexible intramedullary nailing (FIMN), and to compare this to bridge plating and FIMN alone. A length-unstable oblique diaphyseal fracture was created in 15 pediatric sized small femur models. Fracture stabilization was achieved by three constructs: standard retrograde FIMN with two 3.5-mm titanium (Ti) nails (Group 1), FIMN augmented with a two-pin external fixator (Group 2), and a 4.5-mm bridge plate (Group 3). Groups I and II were tested in 10 cycles of axial rotation to 10° in both directions at 0.1 Hz under 36 kg of compression. Torsional stiffness was calculated. Compressive strength was calculated by applying an axial load of 5 mm/min until failure was encountered. Failure was defined as the force required to achieve 10° varus at the fracture site or shortening of 2 cm. Group II demonstrated a greater compressive strength compared to Group I (1067.32 N vs 453.49 N, P < 0.001). No significant difference in torsional stiffness was found between Groups I and II (0.45 vs 0.38 Nm/deg, P = 0.18). Group III showed superior compressive strength and rotational stiffness compared to Groups I and II. In an unstable pediatric femoral shaft fracture model, augmenting FIMN with a two-pin external fixator increased the compressive strength by 147%, but did not increase torsional stiffness. Bridge plating with a 4.5-mm plate provided superior compressive strength and torsional stiffness. |
| Databáze: | OpenAIRE |
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