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Implant augmentation: adding bone cement to improve the treatment of osteoporotic distal femur fractures: a biomechanical study using human cadaver bones.

Wähnert D, Hofmann-Fliri L, Richards RG, Gueorguiev B, Raschke MJ, Windolf M - Medicine (Baltimore) (2014)

Bottom Line: Prior to mechanical testing, bone mineral density (BMD) and local bone strength were determined.Mechanical testing was performed by cyclic axial loading (100 N to 750 N + 0.05N/cycle) using a servo-hydraulic testing machine.As a result, the BMD as well as the axial stiffness did not significantly differ between the groups.The number of cycles to failure was significantly higher in the augmented group with the BMD as a significant covariate.In conclusion, cement augmentation can significantly improve implant anchorage in plating of osteoporotic distal femur fractures.

View Article: PubMed Central - PubMed

Affiliation: Department of Trauma, Hand, and Reconstructive Surgery (DW, MJR), University Hospital Münster, Münster, Germany; and Biomedical Services (LH-F, RGR, BG, MW), AO Research Institute Davos, Davos, Switzerland.

ABSTRACT
The increasing problems in the field of osteoporotic fracture fixation results in specialized implants as well as new operation methods, for example, implant augmentation with bone cement. The aim of this study was to determine the biomechanical impact of augmentation in the treatment of osteoporotic distal femur fractures.Seven pairs of osteoporotic fresh frozen distal femora were randomly assigned to either an augmented or nonaugmented group. In both groups, an Orthopaedic Trauma Association 33 A3 fractures was fixed using the locking compression plate distal femur and cannulated and perforated screws. In the augmented group, additionally, 1 mL of polymethylmethacrylate cement was injected through the screw. Prior to mechanical testing, bone mineral density (BMD) and local bone strength were determined. Mechanical testing was performed by cyclic axial loading (100 N to 750 N + 0.05N/cycle) using a servo-hydraulic testing machine.As a result, the BMD as well as the axial stiffness did not significantly differ between the groups. The number of cycles to failure was significantly higher in the augmented group with the BMD as a significant covariate.In conclusion, cement augmentation can significantly improve implant anchorage in plating of osteoporotic distal femur fractures.

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Related in: MedlinePlus

Photograph on the right is showing an overview of the test setup with the C-arm placed in anteroposterior direction. The detail image on the left shows the 2 pins (1 in the condyle and 1 in the shaft) of the specimen to allow x-ray evaluation. The x-rays in the middle showing 1 specimen before testing (top) and after failure (bottom); change in the pin angle and also in the distance pin tip and screw tip can clearly be seen.
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Figure 1: Photograph on the right is showing an overview of the test setup with the C-arm placed in anteroposterior direction. The detail image on the left shows the 2 pins (1 in the condyle and 1 in the shaft) of the specimen to allow x-ray evaluation. The x-rays in the middle showing 1 specimen before testing (top) and after failure (bottom); change in the pin angle and also in the distance pin tip and screw tip can clearly be seen.

Mentions: In this study, 7 pairs of fresh frozen distal femora with low bone mass were used. The mean age was 87 years (minimun 81; maximum 92); all specimens were from female donors. The proximal femur was replaced by a custom-made standardized polymethylmethacrylate (PMMA) femoral shaft of a length of 13 cm. Plate fixation was performed in a rigid manner to prevent proximal loosening or failure using 3 screws with nuts in the proximal plate holes 2, 4, and 6 (Figure 1). This setup simulates an extraarticular distal femur fracture with a gap of 1.5 cm (AO 33 A3).


Implant augmentation: adding bone cement to improve the treatment of osteoporotic distal femur fractures: a biomechanical study using human cadaver bones.

Wähnert D, Hofmann-Fliri L, Richards RG, Gueorguiev B, Raschke MJ, Windolf M - Medicine (Baltimore) (2014)

Photograph on the right is showing an overview of the test setup with the C-arm placed in anteroposterior direction. The detail image on the left shows the 2 pins (1 in the condyle and 1 in the shaft) of the specimen to allow x-ray evaluation. The x-rays in the middle showing 1 specimen before testing (top) and after failure (bottom); change in the pin angle and also in the distance pin tip and screw tip can clearly be seen.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4616336&req=5

Figure 1: Photograph on the right is showing an overview of the test setup with the C-arm placed in anteroposterior direction. The detail image on the left shows the 2 pins (1 in the condyle and 1 in the shaft) of the specimen to allow x-ray evaluation. The x-rays in the middle showing 1 specimen before testing (top) and after failure (bottom); change in the pin angle and also in the distance pin tip and screw tip can clearly be seen.
Mentions: In this study, 7 pairs of fresh frozen distal femora with low bone mass were used. The mean age was 87 years (minimun 81; maximum 92); all specimens were from female donors. The proximal femur was replaced by a custom-made standardized polymethylmethacrylate (PMMA) femoral shaft of a length of 13 cm. Plate fixation was performed in a rigid manner to prevent proximal loosening or failure using 3 screws with nuts in the proximal plate holes 2, 4, and 6 (Figure 1). This setup simulates an extraarticular distal femur fracture with a gap of 1.5 cm (AO 33 A3).

Bottom Line: Prior to mechanical testing, bone mineral density (BMD) and local bone strength were determined.Mechanical testing was performed by cyclic axial loading (100 N to 750 N + 0.05N/cycle) using a servo-hydraulic testing machine.As a result, the BMD as well as the axial stiffness did not significantly differ between the groups.The number of cycles to failure was significantly higher in the augmented group with the BMD as a significant covariate.In conclusion, cement augmentation can significantly improve implant anchorage in plating of osteoporotic distal femur fractures.

View Article: PubMed Central - PubMed

Affiliation: Department of Trauma, Hand, and Reconstructive Surgery (DW, MJR), University Hospital Münster, Münster, Germany; and Biomedical Services (LH-F, RGR, BG, MW), AO Research Institute Davos, Davos, Switzerland.

ABSTRACT
The increasing problems in the field of osteoporotic fracture fixation results in specialized implants as well as new operation methods, for example, implant augmentation with bone cement. The aim of this study was to determine the biomechanical impact of augmentation in the treatment of osteoporotic distal femur fractures.Seven pairs of osteoporotic fresh frozen distal femora were randomly assigned to either an augmented or nonaugmented group. In both groups, an Orthopaedic Trauma Association 33 A3 fractures was fixed using the locking compression plate distal femur and cannulated and perforated screws. In the augmented group, additionally, 1 mL of polymethylmethacrylate cement was injected through the screw. Prior to mechanical testing, bone mineral density (BMD) and local bone strength were determined. Mechanical testing was performed by cyclic axial loading (100 N to 750 N + 0.05N/cycle) using a servo-hydraulic testing machine.As a result, the BMD as well as the axial stiffness did not significantly differ between the groups. The number of cycles to failure was significantly higher in the augmented group with the BMD as a significant covariate.In conclusion, cement augmentation can significantly improve implant anchorage in plating of osteoporotic distal femur fractures.

Show MeSH
Related in: MedlinePlus