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Bisphosphonates and implants: an overview.

Aspenberg P - Acta Orthop (2009)

View Article: PubMed Central - PubMed

Affiliation: Orthopaedics Section, Department of Clinical and Experimental Medicine, Linköping University, Sweden. per.aspenberg@inr.liu.se

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This remodeling is different from the repair processes following fracture or bone surgery... In bone remodeling, osteoclasts and osteoblasts work closely together—also in a spatial sense—at defined remodeling sites... Their activities are coupled: a decrease in bone resorption due to bisphosphonates leads to a reduction in bone formation to a similar degree... This is clear if you just look at it in the microscope, where you can see large areas of undisturbed bone formation, separate from areas undergoing resorption and remodeling (Figure 1)... Bisphosphonates bind to bone mineral and are taken up by osteoclasts when the latter resorb bone, which inactivates the cell... The second used ibandronate applied locally to the cut bone surface immediately before cementation... A third knee study failed to show any effect of a bisphosphonate upon radiostereometric migration... At first, only small cancellous areas have to take all the load, and they are likely to be compacted... Any effect upon resorption might be hidden in the variation associated with this larger migration... It turned out that those that loosened had migrated statistically significantly more already at 6 months... The highest predictive power was found for migration during the second year... This study investigated patients who were operated in the 1980s, however, when the quality of implants and surgery was still developing... Because this communicates with the space around the loose prosthesis (the “effective joint space”), we hoped to expose the periprosthetic bone to a higher concentration... In a few pilot cases, this did not seem to have any effect.

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Bone resorption and formation are coupled during remodeling, but not during the response to trauma.
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Figure 0002: Bone resorption and formation are coupled during remodeling, but not during the response to trauma.

Mentions: Bisphosphonates are powerful drugs. Their ability to reduce the risk of osteoporotic fractures has saved thousands of people from becoming a fracture patient. Osteoporosis is due to an imbalance in the maintenance remodeling of the skeleton. This remodeling is different from the repair processes following fracture or bone surgery. Because research on the use of bisphosphonates has mostly focused on osteoporosis, their effects on repair processes have long been overlooked. In bone remodeling, osteoclasts and osteoblasts work closely together—also in a spatial sense—at defined remodeling sites. Their activities are coupled: a decrease in bone resorption due to bisphosphonates leads to a reduction in bone formation to a similar degree. Thus, it was long thought that bisphosphonates would only slow down bone repair. However, in bone repair, osteoblasts can work independently. This is clear if you just look at it in the microscope, where you can see large areas of undisturbed bone formation, separate from areas undergoing resorption and remodeling (Figure 1). A reduction in osteoclast activity can therefore be expected to shift the balance between formation and resorption towards increased net bone formation. During bone repair, bisphosphonates have an anti-catabolic, or net anabolic, effect (Figure 2) (Little et al. 2005, Wermelin et al. 2007).


Bisphosphonates and implants: an overview.

Aspenberg P - Acta Orthop (2009)

Bone resorption and formation are coupled during remodeling, but not during the response to trauma.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2823231&req=5

Figure 0002: Bone resorption and formation are coupled during remodeling, but not during the response to trauma.
Mentions: Bisphosphonates are powerful drugs. Their ability to reduce the risk of osteoporotic fractures has saved thousands of people from becoming a fracture patient. Osteoporosis is due to an imbalance in the maintenance remodeling of the skeleton. This remodeling is different from the repair processes following fracture or bone surgery. Because research on the use of bisphosphonates has mostly focused on osteoporosis, their effects on repair processes have long been overlooked. In bone remodeling, osteoclasts and osteoblasts work closely together—also in a spatial sense—at defined remodeling sites. Their activities are coupled: a decrease in bone resorption due to bisphosphonates leads to a reduction in bone formation to a similar degree. Thus, it was long thought that bisphosphonates would only slow down bone repair. However, in bone repair, osteoblasts can work independently. This is clear if you just look at it in the microscope, where you can see large areas of undisturbed bone formation, separate from areas undergoing resorption and remodeling (Figure 1). A reduction in osteoclast activity can therefore be expected to shift the balance between formation and resorption towards increased net bone formation. During bone repair, bisphosphonates have an anti-catabolic, or net anabolic, effect (Figure 2) (Little et al. 2005, Wermelin et al. 2007).

View Article: PubMed Central - PubMed

Affiliation: Orthopaedics Section, Department of Clinical and Experimental Medicine, Linköping University, Sweden. per.aspenberg@inr.liu.se

AUTOMATICALLY GENERATED EXCERPT
Please rate it.

This remodeling is different from the repair processes following fracture or bone surgery... In bone remodeling, osteoclasts and osteoblasts work closely together—also in a spatial sense—at defined remodeling sites... Their activities are coupled: a decrease in bone resorption due to bisphosphonates leads to a reduction in bone formation to a similar degree... This is clear if you just look at it in the microscope, where you can see large areas of undisturbed bone formation, separate from areas undergoing resorption and remodeling (Figure 1)... Bisphosphonates bind to bone mineral and are taken up by osteoclasts when the latter resorb bone, which inactivates the cell... The second used ibandronate applied locally to the cut bone surface immediately before cementation... A third knee study failed to show any effect of a bisphosphonate upon radiostereometric migration... At first, only small cancellous areas have to take all the load, and they are likely to be compacted... Any effect upon resorption might be hidden in the variation associated with this larger migration... It turned out that those that loosened had migrated statistically significantly more already at 6 months... The highest predictive power was found for migration during the second year... This study investigated patients who were operated in the 1980s, however, when the quality of implants and surgery was still developing... Because this communicates with the space around the loose prosthesis (the “effective joint space”), we hoped to expose the periprosthetic bone to a higher concentration... In a few pilot cases, this did not seem to have any effect.

Show MeSH