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The effect of contouring on fatigue resistance of three types of fracture fixation plates

View Article: PubMed Central - PubMed

ABSTRACT

Background: Metallic reconstruction plates used for fracture stabilization typically require intraoperative contouring for patient-specific anatomical fit. Despite this, characterization of plate mechanical properties after contouring has previously been limited.

Background: The objective of this study was to assess whether contouring affects fatigue resistance for three types of Stryker seven-hole stainless steel (SS) 316LVM fracture fixation plates. The hypothesis was that for each plate type, more contouring repetitions would result in lower fatigue resistance.

Methods: Plates were contoured using a bench-top plate bender to ±20° either 0×, 3×, 6×, or 9× (n = 5 per group) and tested in the straight configuration. Cyclic four-point bending was applied in an incremental stepwise staircase approach (one step = 100,000 cycles, 10 Hz) until failure (defined as brittle fracture or plastic deformation of 10° permanent bend). Moment-cycle product (MCP) was computed as the summation of maximum moment × number of cycles and used as the primary measure of fatigue resistance.

Results: No significant differences in fatigue resistance were detected between contouring groups for Basic Fragment Set (BFS) Reconstruction Plates. Significantly lower fatigue resistance was measured for 9× contoured Matta Pelvic System (MPS) Straight Plates compared to 0× contoured plates (p = 0.023). MPS Flex Plates contoured 3× had greater fatigue resistance than 0× contoured (p = 0.031) and 9× contoured plates (p = 0.032).

Conclusions: This work provides fatigue resistance-based evidence that clinicians should avoid high repetitions of contouring for MPS Straight Plates. Meanwhile, BFS Reconstruction Plates and MPS Flex Plates are not negatively affected by contouring. These results allow for improved intraoperative decisions about using or discarding plates after multiple contouring repetitions.

No MeSH data available.


Related in: MedlinePlus

Representative pictures of (a) BFS Reconstruction, (b) MPS Straight, and (c) MPS Flex Plates with no contouring and before fatigue testing; (d) four-point bending test setup on MTS 858 Mini Bionix II (cyclic loads applied as shown, F; inner and outer span lengths Li and Lo, respectively)
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Fig1: Representative pictures of (a) BFS Reconstruction, (b) MPS Straight, and (c) MPS Flex Plates with no contouring and before fatigue testing; (d) four-point bending test setup on MTS 858 Mini Bionix II (cyclic loads applied as shown, F; inner and outer span lengths Li and Lo, respectively)

Mentions: Three types of seven-hole SS Stryker plates were used (provided by Stryker Trauma AG, Selzach, Switzerland, Fig. 1): Stryker Plating System (SPS) Basic Fragment Set (BFS) Reconstruction Plate (REF 432207, SS 316LVM annealed, length = 110 mm, thickness = 3.1 mm, holes for 4.5-mm screws, Fig. 1a), Matta Pelvic System (MPS) Straight Plate (REF 425707, SS 316LVM non-annealed, length = 106.5 mm, thickness = 2.5 mm, holes for 4.5-mm screws, Fig. 1b), and MPS Flex Plate (REF 425757, SS 316LVM annealed, length = 82.5 mm, thickness = 2.5 mm, holes for 4.5-mm screws, Fig. 1c). Plate dimensions and characteristics are included in Table 1. Plates were contoured 0×, 3×, 6×, or 9× (n = 5 for each group). Contouring was performed directly over the middle hole with a standard bench-top plate bender to +20° then −20° as 1× repetition. After the final repetition, the plate was returned to the 0° straight configuration.Fig. 1


The effect of contouring on fatigue resistance of three types of fracture fixation plates
Representative pictures of (a) BFS Reconstruction, (b) MPS Straight, and (c) MPS Flex Plates with no contouring and before fatigue testing; (d) four-point bending test setup on MTS 858 Mini Bionix II (cyclic loads applied as shown, F; inner and outer span lengths Li and Lo, respectively)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5037585&req=5

Fig1: Representative pictures of (a) BFS Reconstruction, (b) MPS Straight, and (c) MPS Flex Plates with no contouring and before fatigue testing; (d) four-point bending test setup on MTS 858 Mini Bionix II (cyclic loads applied as shown, F; inner and outer span lengths Li and Lo, respectively)
Mentions: Three types of seven-hole SS Stryker plates were used (provided by Stryker Trauma AG, Selzach, Switzerland, Fig. 1): Stryker Plating System (SPS) Basic Fragment Set (BFS) Reconstruction Plate (REF 432207, SS 316LVM annealed, length = 110 mm, thickness = 3.1 mm, holes for 4.5-mm screws, Fig. 1a), Matta Pelvic System (MPS) Straight Plate (REF 425707, SS 316LVM non-annealed, length = 106.5 mm, thickness = 2.5 mm, holes for 4.5-mm screws, Fig. 1b), and MPS Flex Plate (REF 425757, SS 316LVM annealed, length = 82.5 mm, thickness = 2.5 mm, holes for 4.5-mm screws, Fig. 1c). Plate dimensions and characteristics are included in Table 1. Plates were contoured 0×, 3×, 6×, or 9× (n = 5 for each group). Contouring was performed directly over the middle hole with a standard bench-top plate bender to +20° then −20° as 1× repetition. After the final repetition, the plate was returned to the 0° straight configuration.Fig. 1

View Article: PubMed Central - PubMed

ABSTRACT

Background: Metallic reconstruction plates used for fracture stabilization typically require intraoperative contouring for patient-specific anatomical fit. Despite this, characterization of plate mechanical properties after contouring has previously been limited.

Background: The objective of this study was to assess whether contouring affects fatigue resistance for three types of Stryker seven-hole stainless steel (SS) 316LVM fracture fixation plates. The hypothesis was that for each plate type, more contouring repetitions would result in lower fatigue resistance.

Methods: Plates were contoured using a bench-top plate bender to ±20° either 0×, 3×, 6×, or 9× (n = 5 per group) and tested in the straight configuration. Cyclic four-point bending was applied in an incremental stepwise staircase approach (one step = 100,000 cycles, 10 Hz) until failure (defined as brittle fracture or plastic deformation of 10° permanent bend). Moment-cycle product (MCP) was computed as the summation of maximum moment × number of cycles and used as the primary measure of fatigue resistance.

Results: No significant differences in fatigue resistance were detected between contouring groups for Basic Fragment Set (BFS) Reconstruction Plates. Significantly lower fatigue resistance was measured for 9× contoured Matta Pelvic System (MPS) Straight Plates compared to 0× contoured plates (p = 0.023). MPS Flex Plates contoured 3× had greater fatigue resistance than 0× contoured (p = 0.031) and 9× contoured plates (p = 0.032).

Conclusions: This work provides fatigue resistance-based evidence that clinicians should avoid high repetitions of contouring for MPS Straight Plates. Meanwhile, BFS Reconstruction Plates and MPS Flex Plates are not negatively affected by contouring. These results allow for improved intraoperative decisions about using or discarding plates after multiple contouring repetitions.

No MeSH data available.


Related in: MedlinePlus