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Straight proximal humeral nails are surrounded by more bone stock in comparison to bent nails in an experimental cadaveric study.

Günther CM, Müller PE, Mutschler W, Sprecher CM, Milz S, Braunstein V - Patient Saf Surg (2014)

Bottom Line: For both straight and bent volumes of interest a considerably declining bone mineral density was found in craniocaudal direction.Mean densities of bent volumes were significantly lower in comparison to their corresponding straight counterparts (p < 0.01) Intra-individual comparison yielded high bivariate correlations of the corresponding Volumes of Interest of the right and the left side (p < 0.01).The high correlation between the Volumes of Interest of the corresponding right and left sides could aid in preoperative planning when considering an intra- or extramedullary approach.

View Article: PubMed Central - HTML - PubMed

Affiliation: University Hospital of Munich, Department of Orthopaedic Surgery, Physical Medicine and Rehabilitation - Campus Großhadern, Ludwig-Maximilians-University, Marchioninistr. 15, 81377 Munich, Germany.

ABSTRACT

Background: In the management of proximal humeral fractures intramedullary implants with bent and straight shape of the proximal part of nail are available. Based on data from previous studies on bone distribution in the humeral head, we hypothesized, that higher densities might exist in the bone stock surrounding straight nails in comparison to their angulated counterparts. With a known positive correlation between bone density and mechanical stability, this could indicate potentially higher rigidity of osteosyntheses done with straight implants.

Methods: We performed high resolution peripheral quantitative computed tomographies of the potential straight and bent implant bearing regions of 27 cadaveric proximal humeri. The acquired data were analyzed for differences between straight and bent Volumes of Interest as well as intra- and interindividual bone stock distribution.

Results: For both straight and bent volumes of interest a considerably declining bone mineral density was found in craniocaudal direction. Mean densities of bent volumes were significantly lower in comparison to their corresponding straight counterparts (p < 0.01) Intra-individual comparison yielded high bivariate correlations of the corresponding Volumes of Interest of the right and the left side (p < 0.01).

Conclusions: Based on the volumetric data a statistically relevant biomechanical superiority of straight shaped implants can be assumed. Since we found a rapid decrease of bone density in cranio-caudal direction, intramedullary implants should be anchored as proximally in the subcortical area as possible to minimize the risk of displacement or cutout. The high correlation between the Volumes of Interest of the corresponding right and left sides could aid in preoperative planning when considering an intra- or extramedullary approach.

No MeSH data available.


Related in: MedlinePlus

Volumetric bone mineral densities of the specimens the specimens from female donors. For symbol captions please refer to Figure 3.
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Figure 5: Volumetric bone mineral densities of the specimens the specimens from female donors. For symbol captions please refer to Figure 3.

Mentions: Bent quarters showed significantly lower BV/TV which reach only 11-57% of their corresponding straight counterparts. The differences are significant on a 0.01 level for the quarters, except the most distal quarter. Similarly, looking at the male and female specimens separately significant differences of varying levels exist for the upper 3 quarters (Figures 3, 4 and 5). While cancellous BV/TV show the highest absolute values, subcortically a rapid decline can be seen moving in cranio-caudal direction. The most distal quarter shows a slight increase in density which was caused by elevated BV/TV levels of the most distal bent quarters. At closer inspection of the data, this elevation is caused by two outliers representing a 42-year old male and a 76-year old woman in the group of the bent quarters. Looking at the straight volumes of the whole sample, differences between the first and the second as well as the third and the fourth adjacent quarters exist (p < 0.05). The bent VOI segments differ from first to second as well as second to third (p < 0.01). No significant differences between right and left humeri were present (p > 0.05). We even found good to very high bivariate correlations between both sides, all of which were significant, with the exception of the proximal bent quarter. The lower correlation values in this region result from a weak correlation in women.


Straight proximal humeral nails are surrounded by more bone stock in comparison to bent nails in an experimental cadaveric study.

Günther CM, Müller PE, Mutschler W, Sprecher CM, Milz S, Braunstein V - Patient Saf Surg (2014)

Volumetric bone mineral densities of the specimens the specimens from female donors. For symbol captions please refer to Figure 3.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4016779&req=5

Figure 5: Volumetric bone mineral densities of the specimens the specimens from female donors. For symbol captions please refer to Figure 3.
Mentions: Bent quarters showed significantly lower BV/TV which reach only 11-57% of their corresponding straight counterparts. The differences are significant on a 0.01 level for the quarters, except the most distal quarter. Similarly, looking at the male and female specimens separately significant differences of varying levels exist for the upper 3 quarters (Figures 3, 4 and 5). While cancellous BV/TV show the highest absolute values, subcortically a rapid decline can be seen moving in cranio-caudal direction. The most distal quarter shows a slight increase in density which was caused by elevated BV/TV levels of the most distal bent quarters. At closer inspection of the data, this elevation is caused by two outliers representing a 42-year old male and a 76-year old woman in the group of the bent quarters. Looking at the straight volumes of the whole sample, differences between the first and the second as well as the third and the fourth adjacent quarters exist (p < 0.05). The bent VOI segments differ from first to second as well as second to third (p < 0.01). No significant differences between right and left humeri were present (p > 0.05). We even found good to very high bivariate correlations between both sides, all of which were significant, with the exception of the proximal bent quarter. The lower correlation values in this region result from a weak correlation in women.

Bottom Line: For both straight and bent volumes of interest a considerably declining bone mineral density was found in craniocaudal direction.Mean densities of bent volumes were significantly lower in comparison to their corresponding straight counterparts (p < 0.01) Intra-individual comparison yielded high bivariate correlations of the corresponding Volumes of Interest of the right and the left side (p < 0.01).The high correlation between the Volumes of Interest of the corresponding right and left sides could aid in preoperative planning when considering an intra- or extramedullary approach.

View Article: PubMed Central - HTML - PubMed

Affiliation: University Hospital of Munich, Department of Orthopaedic Surgery, Physical Medicine and Rehabilitation - Campus Großhadern, Ludwig-Maximilians-University, Marchioninistr. 15, 81377 Munich, Germany.

ABSTRACT

Background: In the management of proximal humeral fractures intramedullary implants with bent and straight shape of the proximal part of nail are available. Based on data from previous studies on bone distribution in the humeral head, we hypothesized, that higher densities might exist in the bone stock surrounding straight nails in comparison to their angulated counterparts. With a known positive correlation between bone density and mechanical stability, this could indicate potentially higher rigidity of osteosyntheses done with straight implants.

Methods: We performed high resolution peripheral quantitative computed tomographies of the potential straight and bent implant bearing regions of 27 cadaveric proximal humeri. The acquired data were analyzed for differences between straight and bent Volumes of Interest as well as intra- and interindividual bone stock distribution.

Results: For both straight and bent volumes of interest a considerably declining bone mineral density was found in craniocaudal direction. Mean densities of bent volumes were significantly lower in comparison to their corresponding straight counterparts (p < 0.01) Intra-individual comparison yielded high bivariate correlations of the corresponding Volumes of Interest of the right and the left side (p < 0.01).

Conclusions: Based on the volumetric data a statistically relevant biomechanical superiority of straight shaped implants can be assumed. Since we found a rapid decrease of bone density in cranio-caudal direction, intramedullary implants should be anchored as proximally in the subcortical area as possible to minimize the risk of displacement or cutout. The high correlation between the Volumes of Interest of the corresponding right and left sides could aid in preoperative planning when considering an intra- or extramedullary approach.

No MeSH data available.


Related in: MedlinePlus