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Biomechanical comparison of semi-rigid pediatric locking nail versus titanium elastic nails in a femur fracture model.

Flinck M, von Heideken J, Janarv PM, Wåtz V, Riad J - J Child Orthop (2014)

Bottom Line: No difference was found in shortening between the PLN and the four 3.0-mm TEN [by 7.0 (3.3-8.4) mm; p = 0.065].The two 3.0-mm TEN did not withstand the maximum shortening of 10.0 mm.PLN provides the greatest stability in all planes compared to TEN models with end caps, even though the difference from the two 4.0-mm or four 3.0-mm TEN models was small.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthopaedics, Skaraborg Hospital, Skövde, Sweden.

ABSTRACT

Background: The treatment for length-unstable diaphyseal femur fractures among school-age children is commonly intramedullary elastic nails, with or without end caps. Another possible treatment is the semi-rigid pediatric locking nail (PLN). The purpose of this biomechanical study was to assess the stability of a length-unstable oblique midshaft fracture in a synthetic femur model stabilized with different combinations of intramedullary elastic nails and with a PLN.

Methods: Twenty-four femur models with an intramedullary canal diameter of 10.0 mm were used. Three groups with various combinations of titanium elastic nails (TEN) with end caps and one group with a PLN were tested. An oblique midshaft fracture was created, and the models underwent compression, rotation, flexion/extension, and a varus/valgus test, with 50 and 100 % of the forces generated during walking in corresponding planes.

Results: We present the results [median (range)] from 100 % loading during walking. In axial compression, the PLN was less shortened than the combination with two 4.0-mm TEN [by 4.4 (3.4-5.4) mm vs. 5.2 (4.8-6.6) mm, respectively; p = 0.030]. No difference was found in shortening between the PLN and the four 3.0-mm TEN [by 7.0 (3.3-8.4) mm; p = 0.065]. The two 3.0-mm TEN did not withstand the maximum shortening of 10.0 mm. In external rotation, the PLN rotated 12.0° (7.0-16.4°) while the TEN models displaced more than the maximum of 20.0°. No model withstood a maximal rotation of 20.0° internal rotation. In the four-point bending test, in the coronal and the sagittal plane, all combinations except the two 3.0-mm TEN in extension withstood the maximum angulation of 20.0°.

Conclusions: PLN provides the greatest stability in all planes compared to TEN models with end caps, even though the difference from the two 4.0-mm or four 3.0-mm TEN models was small.

No MeSH data available.


Related in: MedlinePlus

Frontal radiographs of femur models after fixation. 1 One 5.5-mm pediatric locking nail (PLN), 2 two 4.0-mm titanium elastic nail (TEN) with end cap, 3 four 3.0 mm TEN with end caps, 4 two 3.0 mm TEN with end caps
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Fig1: Frontal radiographs of femur models after fixation. 1 One 5.5-mm pediatric locking nail (PLN), 2 two 4.0-mm titanium elastic nail (TEN) with end cap, 3 four 3.0 mm TEN with end caps, 4 two 3.0 mm TEN with end caps

Mentions: The femur models were 37.5 cm long with an intramedullary canal diameter of 10.0 mm, and were divided into four groups with six femur models in each group. Group one received a 5.5-mm semi-rigid PLN with 8.5-mm proximal geometry and distal bulb (Biomet, Parsippany, NJ, USA). Three groups received three different combinations of TEN with end caps (Synthes, Paoli, PA, USA). Group two received two nails with a diameter of 4.0 mm and group three received four nails with a diameter of 3.0 mm. The last (fourth) group received two nails with a diameter of 3.0 mm (Fig. 1).Fig. 1


Biomechanical comparison of semi-rigid pediatric locking nail versus titanium elastic nails in a femur fracture model.

Flinck M, von Heideken J, Janarv PM, Wåtz V, Riad J - J Child Orthop (2014)

Frontal radiographs of femur models after fixation. 1 One 5.5-mm pediatric locking nail (PLN), 2 two 4.0-mm titanium elastic nail (TEN) with end cap, 3 four 3.0 mm TEN with end caps, 4 two 3.0 mm TEN with end caps
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4340854&req=5

Fig1: Frontal radiographs of femur models after fixation. 1 One 5.5-mm pediatric locking nail (PLN), 2 two 4.0-mm titanium elastic nail (TEN) with end cap, 3 four 3.0 mm TEN with end caps, 4 two 3.0 mm TEN with end caps
Mentions: The femur models were 37.5 cm long with an intramedullary canal diameter of 10.0 mm, and were divided into four groups with six femur models in each group. Group one received a 5.5-mm semi-rigid PLN with 8.5-mm proximal geometry and distal bulb (Biomet, Parsippany, NJ, USA). Three groups received three different combinations of TEN with end caps (Synthes, Paoli, PA, USA). Group two received two nails with a diameter of 4.0 mm and group three received four nails with a diameter of 3.0 mm. The last (fourth) group received two nails with a diameter of 3.0 mm (Fig. 1).Fig. 1

Bottom Line: No difference was found in shortening between the PLN and the four 3.0-mm TEN [by 7.0 (3.3-8.4) mm; p = 0.065].The two 3.0-mm TEN did not withstand the maximum shortening of 10.0 mm.PLN provides the greatest stability in all planes compared to TEN models with end caps, even though the difference from the two 4.0-mm or four 3.0-mm TEN models was small.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthopaedics, Skaraborg Hospital, Skövde, Sweden.

ABSTRACT

Background: The treatment for length-unstable diaphyseal femur fractures among school-age children is commonly intramedullary elastic nails, with or without end caps. Another possible treatment is the semi-rigid pediatric locking nail (PLN). The purpose of this biomechanical study was to assess the stability of a length-unstable oblique midshaft fracture in a synthetic femur model stabilized with different combinations of intramedullary elastic nails and with a PLN.

Methods: Twenty-four femur models with an intramedullary canal diameter of 10.0 mm were used. Three groups with various combinations of titanium elastic nails (TEN) with end caps and one group with a PLN were tested. An oblique midshaft fracture was created, and the models underwent compression, rotation, flexion/extension, and a varus/valgus test, with 50 and 100 % of the forces generated during walking in corresponding planes.

Results: We present the results [median (range)] from 100 % loading during walking. In axial compression, the PLN was less shortened than the combination with two 4.0-mm TEN [by 4.4 (3.4-5.4) mm vs. 5.2 (4.8-6.6) mm, respectively; p = 0.030]. No difference was found in shortening between the PLN and the four 3.0-mm TEN [by 7.0 (3.3-8.4) mm; p = 0.065]. The two 3.0-mm TEN did not withstand the maximum shortening of 10.0 mm. In external rotation, the PLN rotated 12.0° (7.0-16.4°) while the TEN models displaced more than the maximum of 20.0°. No model withstood a maximal rotation of 20.0° internal rotation. In the four-point bending test, in the coronal and the sagittal plane, all combinations except the two 3.0-mm TEN in extension withstood the maximum angulation of 20.0°.

Conclusions: PLN provides the greatest stability in all planes compared to TEN models with end caps, even though the difference from the two 4.0-mm or four 3.0-mm TEN models was small.

No MeSH data available.


Related in: MedlinePlus