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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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The newly designed, mobile, ball-mounted platform for the three-point bending/breaking test. A) The three-point bending/breaking device with the mobile, ball-mounted platform as a contact point for the distal diaphyseal tibia. B) Range of frictionless motion of the mobile, ball-mounted platform on the three-point bending/breaking device.
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Figure 2: The newly designed, mobile, ball-mounted platform for the three-point bending/breaking test. A) The three-point bending/breaking device with the mobile, ball-mounted platform as a contact point for the distal diaphyseal tibia. B) Range of frictionless motion of the mobile, ball-mounted platform on the three-point bending/breaking device.

Mentions: In order to eliminate unwanted frictional forces that occur during the lengthening of the tibia diaphysis in the previously used metaphyseal bending and breaking test designs, we created a new platform design for resistance free positioning of the bone (Figure 1).We consider the movement of the distal end of the tibia caused by the diaphyseal lengthening on a fixed surface as the essential problem, since through this movement unwanted friction is created. This friction inaccurately increases the necessary force that causes a bending or breaking in the metaphyseal tissue. The new mobile, ball-mounted platform is hypothesized to allow the tibia to lengthen completely free of resistance along its diaphyseal axis during testing and thus prevents development of unwanted friction caused by the movement of the distal diaphysis over the fixed aluminum block (Figure 2).Our three-point bending/breaking device for the rat (Figure 2) consisted of a base measuring 9.5 cm × 4 cm × 0.3 cm (length × width × height). On the upper side it had two 6.5 cm grooves which were 0.16 cm apart. Each groove was 0.01 cm deep and 0.02 cm wide and in each glided 5 stainless steel balls, with every ball having had a diameter of 0.04 cm.


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)

The newly designed, mobile, ball-mounted platform for the three-point bending/breaking test. A) The three-point bending/breaking device with the mobile, ball-mounted platform as a contact point for the distal diaphyseal tibia. B) Range of frictionless motion of the mobile, ball-mounted platform on the three-point bending/breaking device.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 2: The newly designed, mobile, ball-mounted platform for the three-point bending/breaking test. A) The three-point bending/breaking device with the mobile, ball-mounted platform as a contact point for the distal diaphyseal tibia. B) Range of frictionless motion of the mobile, ball-mounted platform on the three-point bending/breaking device.
Mentions: In order to eliminate unwanted frictional forces that occur during the lengthening of the tibia diaphysis in the previously used metaphyseal bending and breaking test designs, we created a new platform design for resistance free positioning of the bone (Figure 1).We consider the movement of the distal end of the tibia caused by the diaphyseal lengthening on a fixed surface as the essential problem, since through this movement unwanted friction is created. This friction inaccurately increases the necessary force that causes a bending or breaking in the metaphyseal tissue. The new mobile, ball-mounted platform is hypothesized to allow the tibia to lengthen completely free of resistance along its diaphyseal axis during testing and thus prevents development of unwanted friction caused by the movement of the distal diaphysis over the fixed aluminum block (Figure 2).Our three-point bending/breaking device for the rat (Figure 2) consisted of a base measuring 9.5 cm × 4 cm × 0.3 cm (length × width × height). On the upper side it had two 6.5 cm grooves which were 0.16 cm apart. Each groove was 0.01 cm deep and 0.02 cm wide and in each glided 5 stainless steel balls, with every ball having had a diameter of 0.04 cm.

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