Dual X-ray absorptiometry for the evaluation of bone density from the proximal femur after total hip arthroplasty: Analysis protocols and reproducibility (original) (raw)
Related papers
The Journal of Arthroplasty, 1996
To define the precision (reproducibility) of measurement of periprosthetic bone mineral density and bone mineral content, dual-energy x-ray absorptiometry scans were obtained on 45 randomly selected patients who had had a unilateral total hip arthroplasty within the previous 3 years. The coefficients of variation of the bone mineral density in the proximal Gruen zones were 5.0 and 5.3%, corresponding to errors of 0.07 and 0.11 g/cm a. The coefficients of variation of the bone mineral density for the distal zones averaged 2.8%, with an error of 0.08 glcm 2. The coefficients of variation of the bone mineral content were 4.8 and 2.9% for the proximal and distal zones. The contralateral femur was also scanned in 32 of the patients. For the contralateral femur bone mineral density, the coefficients of variation were 5.0% for the proximal zones and 4.8% for the distal zones. The bone mineral content was 6.0% for the contralateral regions. These results imply that differences in bone mineral density greater than 0.16 g/cm 2 (2 standard errors) can be reliably measured. Dualenergy x-ray absorptiometry therefore provides a highly reproducible technique for quantitatively monitoring the changes in bone density that occur after total hip arthroplasty.
The Journal of Arthroplasty, 1996
To define the precision (reproducibility) of measurement of periprosthetic bone mineral density and bone mineral content, dual-energy x-ray absorptiometry scans were obtained on 45 randomly selected patients who had had a unilateral total hip arthroplasty within the previous 3 years. The coefficients of variation of the bone mineral density in the proximal Gruen zones were 5.0 and 5.3%, corresponding to errors of 0.07 and 0.11 g/cm a. The coefficients of variation of the bone mineral density for the distal zones averaged 2.8%, with an error of 0.08 glcm 2. The coefficients of variation of the bone mineral content were 4.8 and 2.9% for the proximal and distal zones. The contralateral femur was also scanned in 32 of the patients. For the contralateral femur bone mineral density, the coefficients of variation were 5.0% for the proximal zones and 4.8% for the distal zones. The bone mineral content was 6.0% for the contralateral regions. These results imply that differences in bone mineral density greater than 0.16 g/cm 2 (2 standard errors) can be reliably measured. Dualenergy x-ray absorptiometry therefore provides a highly reproducible technique for quantitatively monitoring the changes in bone density that occur after total hip arthroplasty.
European Journal of Nuclear Medicine, 1992
Two dual energy X-ray absorptiometric (DXA) instruments have recently become commercially available for local bone densitometry: the QDR-1000 (Hologic Inc.) and the DPX (Lunar Radiation Corp.). We report the precision, influence of femoral rotation, correla~tion and agreement of bone mineral measurements of the proximal femur by these two instruments. In vitro (femur phantom) short-term precision was 1.1%-3.5%, and the long-term precision was 1.2% 3.8%. In vivo (groups of 10 premenopausal and 10 postmenopausal women) short-term precision of duplicate measurements was 1.6%-4.7%, and long-term precision was 1.9%-5.5%. Overall, the precision for Ward's triangle was over 3% and that for the femoral neck and trochanter, 2%-3%. Rotation of a femur phantom produced a statistically significant change in the bone mineral density (BMD) of the femoral neck. Within a clinically relevant range of femoral rotation (20 ° inward rotation _+5 °) the coefficient of variation (CV%) increased by a mean factor of 1.1-1.4. Although the correlation (r < 0.9) between BMD measurements of the proximal femur by the DPX and QDR-1000 in 30 postmenopausal women was high, there was lack of agreement between the two instruments. We found no statistically significant differences between the right and left femur in 30 postmenopausal women. A bilateral femur scan took a mean total time of about 22 rain. We conclude that with the introduction of DXA instruments, the precision of bone mineral measurements of the proximal femur has improved. However, for comparability between commercially available DXA instruments, it might be advantageous if units were standardized.
Journal of Bone and Mineral Research, 2001
Gruen zones during the first 3 months, ranging from 3.4% to 14.4% (p < 0.05 to p < 0.001). At the end of the first year, the most remarkable decrease in BMD was found in the calcar (zone 7; ؊22.9%). During the second postoperative year, a slight restoration of periprosthetic bone mass was recorded. During the third year, no significant changes in BMD were found. The preoperative BMD was the only factor that was significantly related to the periprosthetic bone loss. Clearly, the early periprosthetic bone loss noticed during the 3 months after THA is caused by mainly limited weight bearing to the operated hip and stress shielding. We suggest that the restoration of bone mass is a sign of successful osteointegration between bone and metallic implant. DXA is a suitable tool to follow the bone response to prosthetization and will increase our knowledge on the behavior of bone after THA. (J Bone Miner Res 2001;16:1056 -1061)
Changes in bone mineral density around a stable uncemented total hip arthroplasty
International Orthopaedics, 1997
Changes in bone mineral density (BMD) around the components of the Zweymueller total hip arthroplasty were measured, using dual energy X-ray absorptiometry, in 36 women who were operated on for primary osteoarthritis. Seven regions of interest were studied. No changes occurred around the screw socket and the greater trochanter, but there was a significant reduction of BMD, only when measured immediately after the operation at the lesser trochanter and at the distal femoral cortex lateral and medial to the tip of the stem. These changes were not related to the age of the patients. The reduction of BMD in the femur was mostly associated with areas where bone had been removed at operation. The press-fit fixation of the Zweymueller stem and the maintenance of its fixation with time did not induce further bone turnover around it. The absence of changes in bone mineral density was due to the relatively small amount of subchondral removed and to the continued stable fixation of the socket.
Osteoporosis International, 1991
Bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry (DEXA) in 133 normal females on five regions of the femoral site: neck, trochanteric, intertrochanteric, Ward's triangle, and total area of the proximal femur. One hundred and twenty-five women (56 older than 65, range 65-97, and 69 with an age range of 21-65) were also examined for spinal bone mineral density. The mean in vivo precision (CV%) of the measurements with respositioning assessed on five young and eight elderly patients was ranged from 0.7% to 1.7% but lower for Ward's triangle (CV=2.95% and 3.87%). Between 30 and 90 years, a linear age-related bone mineral decrease was found at all sites with a similar magnitude of bone loss for the femoral neck, total or intertrochanteric regions (-33% to -39%). A greater decrease was found for the Ward's triangle region (-61%). In the subgroup of elderly women (65-97 years old), the lumbar BMD measured with an anteroposterior incidence did not decrease significantly with age, contrasting with an average 27% decrease of the BMD of the hip between 65 and 90 years of age.
The Journal of Arthroplasty, 1997
Bone ingrowth into uncemented femoral implants with proximal porous coatings has been designed to avoid proximal stress shielding and preserve femoral strength. Dual-energy x-ray absorptiometry allows repeated quantitative analysis of anteroposterior scans of the proximal femur. By use of dual-energy x-ray absorptiometry and qualitative radiographic changes, 31 total hip arthroplasties with an individually designed, proximally porous-coated prosthesis were evaluated after surgery and at intervals up to 2 years. All implants appeared to achieve successful bone ingrowth and subsequent remodeling. At the most proximal level around the neck osteotomy, the postoperative loss of bone density at 6 months was -14.5%, which persisted at 24 months with -11.6%. At the level of the distal portion of the porous coating in the lower metaphysis, the density change was -8.7%, but bone had remodeled at 24 months with a change in density of only -1.0% compared with the immediate postoperative scan. With a design that results in reliable proximal ingrowth, this study predicts that after an initial decline in bone density, a positive bone remodeling response occurs that could lead to long-term stable fixation of the femoral implant. Key words: dual-energy x-ray absorptiometry, bone remodeling, uncemented femoral implant, proximal porous coating, femur, hip prosthesis.
Bone loss around failed femoral implant measured by dual-energy X-ray absorptiometry
2000
quantity of bone near a metallic implant. 5,6,8 Changes not already visible on standard X-ray films can be detected with DXA. 1 Radiation for the patient is minimal (under 5 mrem/scan), 7 and the error in repetitive measurements is also small 1.0%-5.3%. 8 Periprosthetic bone loss around failed total hip arthroplasty (THA) has not, however, been quantitated so far. The aim of this study was to measure bone mineral density (BMD) around the loosened femoral stem, using DXA to establish a quantative model of bone loss around the loosened implant. Patients and methods Between December 1993 and August 1997, BMD measurements were performed preoperatively in 30 patients who came for revision THAs at Kuopio University Hospital. Nineteen of these patients (13 women, 6 men) had been unilaterally operated on and were selected for this study. The indication for primary arthroplasty was primary arthrosis in 79% (15/19) of the patients, hip fracture in 16% (3/19), and secondary arthrosis in 5% (1/19) (Table 1). The secondary arthrosis was caused by longstanding corticosteroid treatment for polymyalgia rheumatica. The average age at the time of the revision THA was 69 years (range, 48-82 years). The average time between the primary and revision arthroplasties was 5.2 years (range, 0.4-12.3 years). The femoral implants and fixation method used in the primary operation differed among patients (Table 1). Aseptic loosening was the reason for revision arthroplasty in all patients. Five of these revision arthroplasties were done quite soon (at an average of 2.7 years) after the primary arthroplasty. The loosening of the arthroplasties that failed early was actually caused by cement failure (Boneloc; Polymers Reconstructive, Farum, Denmark). 15 On the Endo-Klinik scale, 6 patients had grade-1 loosening and 13 had grade-2. 2
Calcified Tissue International, 1998
Bone quality is important for the success of joint prostheses implantation, and the assessment of bone density after total knee arthroplasty by means of dual-energy X-ray absorptiometry may be useful for monitoring implant stability. The aim of this study is to suggest a validated analysis protocol for the assessment of bone status after total knee arthroplasty. A dedicated densitometric analysis protocol of five regions of interest was designed, and 10 subjects who had received an uncemented knee prosthesis (8 females and 2 males, aged 55-74 years) underwent three consecutive scans in posteroanterior and lateral projections, with repositioning after each scan to test the suitability and reproducibility of the protocol. The reproducibility of the measurement of bone mineral content and density in the femoral and tibial regions ranged, respectively, from 2.1% to 4.1%, from 0.9% to 2.6% for the posteroanterior scans, and from 2.7% to 5.6% and from 2.3% to 4.7% for the lateral scans, depending on the considered region. Our results confirm that the suggested protocol allows precise assessment of bone mineral content and density, and that dual-energy X-ray absorptiometry is reliable for the evaluation of bone mass around prosthetic implants.
Journal of Clinical Densitometry
Dual-energy X-ray absorptiometry (DXA) is a technique enabling the measurement of bone mineral density (BMD) around prostheses after hip resurfacing arthroplasty (HRA). In this study, we evaluated the consistency of different DXA acquisition modes with 33 patients who had undergone HRA. Patients were scanned with DXA immediately after surgery and at 3-, 6-, and 12-mo time points. All the patients were scanned with dual femur and orthopedic hip acquisition modes and analyzed using 10-region ROI model. With both acquisition modes, a statistically significant decrease ( p ! 0.05, Wilcoxon's test) in BMD at 3 mo was revealed in 3 ROIs, located to upper and lateral upper femur. Both acquisition modes detected similarly ( p ! 0.01) preservation of the femoral bone stock within 12 mo in all but 1 ROI. The applied acquisition protocols involved the use of different footplates for hip fixation. Because the differences between acquisition modes ranged between þ1.6% and À7.1% and the reproducibility of BMD values can vary by as much as 28% due to hip rotation, it is proposed that both dual femur and orthopedic hip acquisition modes can be used to monitor the changes in BMD after HRA. However, the same hip rotation is recommended for all DXA measurements.