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A novel device for resistance-free biomechanical testing of the metaphysis of long bones.

Mackert GA, Hirche C, Harhaus H, Kotsougiani D, Hoener B, Kneser U, Harhaus L - BMC Musculoskelet Disord (2014)

Bottom Line: In the evaluation of both testing procedures, the results of the right and left tibiae were compared according to the rat they originated from.The mean failure Load (fL) did not differ significantly (p < 0.231) between Group 1: 81.34 ± 11.972 N SD and Group 2: 79.63 ± 10.345 N SD.We suggest that the new ball-mounted platform device, when compared to other existing techniques, generates more accurate test results when used in the three-point bending/breaking test of the metaphysis of long bones.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department for Hand-, Plastic- and Reconstructive Surgery - Burn Care Center - BG-Trauma Clinic Ludwigshafen, Department for Plastic Surgery of the University of Heidelberg, Ludwig-Guttmann-Str, 13, 67071 Ludwigshafen, Germany. leila.harhaus@bgu-ludwigshafen.de.

ABSTRACT

Background: Biomechanical testing is an essential component of bone research. In order to test the metaphyseal region of long bones, a typical location for the nowadays increasing field of osteoporotic bone changes, three-point bending and breaking test devices are suitable and widely used. The aim of our study was to increase the effectiveness of this method by using a newly developed ball-mounted platform design. This new design eliminates the negative effects of friction, present in previous studies, caused by the lengthening of the distal tibia along its diaphyseal axis while sliding over the surface of a fixed aluminum block.

Methods: 70 tibiae of 35 twelve week old, female Sprague Dawley rats were separated into two groups for a metaphyseal bending/breaking test. Group 1 was made up of the rat's right tibiae, Group 2 of the left tibiae. Group 1 was tested on a solid metal block according to previously established testing devices whereas Group 2 was tested on the newly designed device: the resistance-free gliding, ball-mounted platform. Stiffness (N/mm), yield Load (N), and failure Load (N) were registered. In the evaluation of both testing procedures, the results of the right and left tibiae were compared according to the rat they originated from.

Results: Stiffness (S) showed highly significant differences (p = 0.002) with 202.25 ± 27.010 N/mm SD (Group 1) and 184.66 ± 35.875 N/mm SD (Group 2). Yield Load (yL) showed highly significant differences (p < 0.001) with 55.31 ± 13.074 N SD (Group1) and 37.17 ± 12.464 N SD (Group2). The mean failure Load (fL) did not differ significantly (p < 0.231) between Group 1: 81.34 ± 11.972 N SD and Group 2: 79.63 ± 10.345 N SD.

Conclusions: We therefore conclude that, used in the three-point bending/breaking test, the mobile, ball-mounted platform device is able to efficiently eliminate the influence of friction in terms of stiffness and yield load. Failure Load was not affected. We suggest that the new ball-mounted platform device, when compared to other existing techniques, generates more accurate test results when used in the three-point bending/breaking test of the metaphysis of long bones.

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Related in: MedlinePlus

Schematic drawing of the stamp which was connected to the ZWICK-testing machine and lowered onto the marked location of tibia metaphysis. The radius of the tip is 2.5 mm. The dimensions in the drawing are all in millimeter (mm).
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Figure 4: Schematic drawing of the stamp which was connected to the ZWICK-testing machine and lowered onto the marked location of tibia metaphysis. The radius of the tip is 2.5 mm. The dimensions in the drawing are all in millimeter (mm).

Mentions: A distance of 5 mm distal the epiphyseal line was measured and marked to define the metaphysis. Then the condyles of the proximal tibia were placed into the head block in between the two pins and fitted through manual adjustment. The distal diaphysis was placed, depending on which group the tibia belonged to, either on the surface of the aluminum block or into the 0.03 cm wide and 0.01 cm deep groove of the ball-mounted, mobile platform.The stamp, which was connected to the ZWICK-testing machine type Z020/TND (ZWICK-/Roell, Ulm, Germany), was 3.45 cm long, 0.7 cm wide and 0.25 cm in diameter with a rounded tip (Figure 4). The stamp was aligned in such a manner, that it would administer the pressure directly onto the marked metaphyseal area, measured 0.5 cm distal of the epiphyseal line. It was automatically lowered onto the ventral metaphysis of the tibia to start the three-point bending/breaking test.


A novel device for resistance-free biomechanical testing of the metaphysis of long bones.

Mackert GA, Hirche C, Harhaus H, Kotsougiani D, Hoener B, Kneser U, Harhaus L - BMC Musculoskelet Disord (2014)

Schematic drawing of the stamp which was connected to the ZWICK-testing machine and lowered onto the marked location of tibia metaphysis. The radius of the tip is 2.5 mm. The dimensions in the drawing are all in millimeter (mm).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4125708&req=5

Figure 4: Schematic drawing of the stamp which was connected to the ZWICK-testing machine and lowered onto the marked location of tibia metaphysis. The radius of the tip is 2.5 mm. The dimensions in the drawing are all in millimeter (mm).
Mentions: A distance of 5 mm distal the epiphyseal line was measured and marked to define the metaphysis. Then the condyles of the proximal tibia were placed into the head block in between the two pins and fitted through manual adjustment. The distal diaphysis was placed, depending on which group the tibia belonged to, either on the surface of the aluminum block or into the 0.03 cm wide and 0.01 cm deep groove of the ball-mounted, mobile platform.The stamp, which was connected to the ZWICK-testing machine type Z020/TND (ZWICK-/Roell, Ulm, Germany), was 3.45 cm long, 0.7 cm wide and 0.25 cm in diameter with a rounded tip (Figure 4). The stamp was aligned in such a manner, that it would administer the pressure directly onto the marked metaphyseal area, measured 0.5 cm distal of the epiphyseal line. It was automatically lowered onto the ventral metaphysis of the tibia to start the three-point bending/breaking test.

Bottom Line: In the evaluation of both testing procedures, the results of the right and left tibiae were compared according to the rat they originated from.The mean failure Load (fL) did not differ significantly (p < 0.231) between Group 1: 81.34 ± 11.972 N SD and Group 2: 79.63 ± 10.345 N SD.We suggest that the new ball-mounted platform device, when compared to other existing techniques, generates more accurate test results when used in the three-point bending/breaking test of the metaphysis of long bones.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department for Hand-, Plastic- and Reconstructive Surgery - Burn Care Center - BG-Trauma Clinic Ludwigshafen, Department for Plastic Surgery of the University of Heidelberg, Ludwig-Guttmann-Str, 13, 67071 Ludwigshafen, Germany. leila.harhaus@bgu-ludwigshafen.de.

ABSTRACT

Background: Biomechanical testing is an essential component of bone research. In order to test the metaphyseal region of long bones, a typical location for the nowadays increasing field of osteoporotic bone changes, three-point bending and breaking test devices are suitable and widely used. The aim of our study was to increase the effectiveness of this method by using a newly developed ball-mounted platform design. This new design eliminates the negative effects of friction, present in previous studies, caused by the lengthening of the distal tibia along its diaphyseal axis while sliding over the surface of a fixed aluminum block.

Methods: 70 tibiae of 35 twelve week old, female Sprague Dawley rats were separated into two groups for a metaphyseal bending/breaking test. Group 1 was made up of the rat's right tibiae, Group 2 of the left tibiae. Group 1 was tested on a solid metal block according to previously established testing devices whereas Group 2 was tested on the newly designed device: the resistance-free gliding, ball-mounted platform. Stiffness (N/mm), yield Load (N), and failure Load (N) were registered. In the evaluation of both testing procedures, the results of the right and left tibiae were compared according to the rat they originated from.

Results: Stiffness (S) showed highly significant differences (p = 0.002) with 202.25 ± 27.010 N/mm SD (Group 1) and 184.66 ± 35.875 N/mm SD (Group 2). Yield Load (yL) showed highly significant differences (p < 0.001) with 55.31 ± 13.074 N SD (Group1) and 37.17 ± 12.464 N SD (Group2). The mean failure Load (fL) did not differ significantly (p < 0.231) between Group 1: 81.34 ± 11.972 N SD and Group 2: 79.63 ± 10.345 N SD.

Conclusions: We therefore conclude that, used in the three-point bending/breaking test, the mobile, ball-mounted platform device is able to efficiently eliminate the influence of friction in terms of stiffness and yield load. Failure Load was not affected. We suggest that the new ball-mounted platform device, when compared to other existing techniques, generates more accurate test results when used in the three-point bending/breaking test of the metaphysis of long bones.

Show MeSH
Related in: MedlinePlus