The precision and influence of rotation for measurements of bone mineral density of the distal femur following total knee arthroplastyA methodological study using DEXA

Therbo, Matthias; Petersen, Michael Mørk; Schrøder, Henrik Morville; Nielsen, Peter Aadal; Zerahn, Bo; Lund, B.

doi:10.1080/00016470310018199

Cited by 25 publications

(12 citation statements)

References 13 publications

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“…However, during longitudinal assessments, other sources of error would need to be considered. Repositioning the subjects' limbs from day to day [20][21][22][23] and significant changes in soft tissue (disuse atrophy of muscle) may contribute to error during longitudinal studies using DXA scans. Accordingly, an intervention that has a small effect (≈10%) may be very difficult to reliably measure at the distal femur and proximal tibia, once all sources of error using DXA are taken into account.…”

Section: Discussionmentioning

confidence: 99%

Bone Mineral Density After Spinal Cord Injury: A Reliable Method for Knee Measurement

Shields¹,

Schlechte²,

Dudley-Javoroski³

et al. 2005

Archives of Physical Medicine and Rehabilitation

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Objectives-To test the interrater reliability of a standardized method to analyze knee bone mineral density (BMD) using dual-energy x-ray absorptiometry (DXA); to compare spine, hip, and knee BMD of people with spinal cord injury (SCI) with able-bodied controls; and to determine the relation between hip BMD and knee BMD in SCI and able-bodied subjects. Design-Criterion standard and masked comparison. Setting-Primary care university hospital.Participants-A convenience sample of 11 subjects with complete SCI was age and sex matched with 11 able-bodied control subjects. Interventions-Not applicable.Main Outcome Measures-Four raters analyzed regions of interest according to operational definitions recently developed to standardize the analysis of BMD of the knee. Subjects with chronic SCI and matched controls underwent conventional DXA scans of the spine and hips and "less conventional" scans of the distal femurs and proximal tibias. The relation between hip and knee BMD was analyzed.Results-The knee measurements were highly reliable (femur intraclass correlation coefficient model 2,1 [ICC 2,1 ]=.98; tibia ICC 2,1 =.89). Subjects with SCI had lower BMD values than controls at all hip and knee sites (P<.05). Lumbar spine BMD did not differ between groups. Hip BMD was moderately predictive of distal femur BMD (R 2 =.67), but less correlated with the proximal tibia (R 2 =.38).Conclusions-Knee BMD can be reliably analyzed using DXA with this protocol. Subjects with SCI have diminished knee and hip BMD. Low hip BMD is associated with low distal femur BMD. KeywordsFractures; Osteoporosis; Paralysis; Rehabilitation; X-ray absorptiometry; dual energy No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the authors or upon any organization with which the authors are associated. Osteoporosis is a severe and debilitating secondary complication of complete spinal cord injury (SCI). Bone mineral density (BMD) of the paralyzed extremities declines precipitously in the first 2 years after SCI, eventually reaching a level below fracture threshold. 1-4 Between 1% and 6% of people with SCI will sustain fractures in their paralyzed extremities. [5][6][7] Fractures are often caused by trivial insults to the limbs 5,7,8 that people with SCI frequently encounter during everyday mobility. NIH Public AccessThe main instrument used to measure BMD is dual-energy x-ray absorptiometry (DXA). In postmenopausal women, DXA-based BMD T scores are used to diagnose osteoporosis and the technique is valuable for monitoring longitudinal changes in bone density. The progression of osteoporosis after SCI has been described for the hip and lumbar spine. In general, hip BMD declines rapidly for the first several months, then declines more slowly until reaching equilibrium at 12 to 16 months postinjury. 1,2,4 Lumbar spine BMD generally does not decline and may even increase after SCI. 4,9 By far the most common sites for fracture after SCI are the distal femu...

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Section: Discussionmentioning

confidence: 99%

Bone Mineral Density After Spinal Cord Injury: A Reliable Method for Knee Measurement

Shields¹,

Schlechte²,

Dudley-Javoroski³

et al. 2005

Archives of Physical Medicine and Rehabilitation

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“…The values of bone mineral density measurement are not affected by the use of bone cement around the prosthetic implants 23 . The Hologic DEXA system (Hologic, Waltham, Massachusetts) was used in this study.…”

Section: Bone Mineral Densitymentioning

confidence: 99%

Three-Year Changes in Bone Mineral Density Around the Knee After a Six-Month Course of Oral Alendronate Following Total Knee Arthroplasty

Wang

et al. 2006

The Journal of Bone & Joint Surgery

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“…The change in loading pattern may according to Wolff's law (J. Wolff, 1892) lead to hypertrophic or atrophic bone zones adjacent to the stem. The degree of bone remodelling depends on design and flexibility of the stem (Ang et al, 1997;Zerahn et al, 1998;Gibbons et al, 2001), the method of fixation (Kroger et al, 1998), bone quality (Therbo et al, 2003), and probably the periprosthetic vascularisation (Santavirta et al, 1990;Hupel et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Early periprosthetic femoral bone remodelling using different bearing material combinations in total hip arthroplasties: a prospective randomised study

Nygaard

Zerahn²,

Bruce³

et al. 2004

eCM

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The present study was performed to test the hypothesis that different bearing materials have an impact on femoral bone remodelling within the first year after a total hip arthroplasty. A total of 225 patients with osteoarthrosis of the hip or avascular necrosis of the femoral head were included in this randomised prospective study. All patients had an identical hybrid total hip arthroplasty (cemented BiMetric stem and cementless RingLoc acetabular cup) except for the bearing materials: polyethylene-on-zirconia (n = 78), CoCr-on-CoCr (n = 71), or alumina-on-alumina (n = 76). Bone mineral density (BMD) was measured with Dual-energy X-ray absorptiometry (DEXA) in seven Gruen zones adjacent to the femoral implant. The DEXA scan was performed within one week after surgery and was repeated one year postoperatively. There was no significant difference in periprosthetic BMD change between the three groups. After twelve months the relative BMD decrease was highest in the proximal part of the femur, -6.2% in the greater trochanter region and -12.7% in the lesser trochanter region. In the distal zones the relative BMD decrease was -5.3, -4.2, -2.1, -2.3, and -5.6%, respectively. The use of different bearing materials had no significant impact on femoral bone remodelling adjacent to the cemented hip stem within one year after surgery.

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The precision and influence of rotation for measurements of bone mineral density of the distal femur following total knee arthroplastyA methodological study using DEXA

Cited by 25 publications

References 13 publications

Bone Mineral Density After Spinal Cord Injury: A Reliable Method for Knee Measurement

Bone Mineral Density After Spinal Cord Injury: A Reliable Method for Knee Measurement

Three-Year Changes in Bone Mineral Density Around the Knee After a Six-Month Course of Oral Alendronate Following Total Knee Arthroplasty

Early periprosthetic femoral bone remodelling using different bearing material combinations in total hip arthroplasties: a prospective randomised study

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