Bone mineral density difference between right and left hip during ageing

Establishing a Total Hip T-Score Threshold to Measure Contralateral Hip Bone Mineral Density: Avoiding Missed Diagnosis of Osteoporosis

Bone mineral density (BMD) of the hip is routinely measured unilaterally, but can differ between left and right. This study aimed to establish total hip T-score thresholds for measuring contralateral hip BMD, to avoid missing the diagnosis of osteoporosis. In 4914 participants (2709 females) in the Busselton Healthy Ageing Study, BMD of both hips and lumbar spine (L1-L4) was measured by dual-energy x-ray absorptiometry (DXA) using a GE Lunar Prodigy Pro densitometer. Least significant change (LSC) was calculated according to International Society for Clinical Densitometry recommendations. For participants whose left-right total hip BMD difference exceeded LSC, the 95th percentile of the difference in T-score was calculated, then added to -2.5 (the cut-off for osteoporosis) to derive T-score thresholds for measuring contralateral hip to avoid a missed diagnosis in 95% of individuals. Participant mean age (±SD) was 57.4 ± 5.8 years; total hip T-score was 0.7 ± 0.1 in males and -0.2 ± 1.1 in females. Left and right total hip BMD were highly correlated (r = 0.943 for males, 0.959 for females), but in 56.2% of males and 50.0% of females, the left-right difference exceeded the LSC of 0.026 g/cm². In these participants, the 95th percentile of difference in T-score between two hips was 0.872 in males and 0.742 in females. This gave T-score thresholds for measuring contralateral total hip BMD of -1.6 (males) and -1.8 (females). When total hip T-score is between -1.6 and -2.5 (males), or between -1.8 and -2.5 (females), measuring contralateral hip BMD could avoid a missed diagnosis of osteoporosis.

Dominant vs. non-dominant hip comparison in bone mineral density in young sporting athletes

To explore differences in bone mineral density (BMD) between dominant and non-dominant hip within levels of sport impact. BMD was higher in the non-dominant hip in high-impact sports, whereas the dominant hip had increased BMD for low-impact sports. The side-to-side differences were relatively small and not clinically relevant.

PURPOSE

It is unknown whether there is difference in BMD at the hip between dominant and non-dominant sides in young athletes. The aims of this study were to explore the dominant-non-dominant differences in hip BMD in young athletes participating in low- and high-impact sports and to assess the effect of ground force impact on BMD.

METHODS

Data was collected on University of Oxford athletes and controls (CG) between 2016 and 2018. Athletes were classified into two groups: high-impact sports (HIG) and low-impact sports (LIG). Total and regional measurements of both hips' BMD were recorded using a dual-energy X-ray absorptiometry (DXA). Linear regression method was used to assess differences in BMD between and within groups.

RESULTS

One hundred ninety-four athletes (HIG: n = 89, LIG: n = 105) and 48 controls were included in this study. Total hip and femoral neck BMD was higher in athletes compared to the CG (p < 0.01), with HIG recording highest levels of BMD. The BMD difference between the dominant and non-dominant sides was significant in the LIG, with BMD being higher in the dominant side. Conversly, BMD was higher in the non-dominant hip within the HIG. However, the hip asymmetries were not clinically relevant (%BMD difference < 3%). A significant interaction between side and sport group on BMD was observed.

CONCLUSIONS

High-impact sports had significantly higher BMD compared with low-impact sports and CG. BMD in the dominant hip was significantly higher for the LIG and lower in the HIG; however, differences were not clinically relevant.

FRAX Calculated without BMD Resulting in a Higher Fracture Risk Than That Calculated with BMD in Women with Early Breast Cancer

BACKGROUND AND PURPOSE

The aim of this study was to investigate the importance of including the measurement of bone mineral density (BMD) in reliable fracture risk assessment for women diagnosed with early nonmetastatic breast cancer (EBC) before AI treatment if zoledronic acid is not an option.

MATERIAL AND METHODS

One hundred and sixteen women with EBC were included in the study before initiating AI treatment. Most participants were osteopenic. The 10-year probability of hip fracture and major osteoporotic fracture was calculated with and without BMD based on clinical information collected at baseline using the fracture risk assessment (FRAX) tool. To compare data, the nonparametric tests were used.

RESULTS

There was a significant difference (p<0.001) in the number of high-risk and low-risk FRAX score of hip fracture between before and after including BMD values. The high-risk category decreased by 50.9%, while the low-risk category increased by 42.9%. In FRAX score of major osteoporotic the findings were similar (p<0.001): The high-risk and moderate-risk category decreased by 70.4% and 4.9%, respectively, while the low-risk category increased by 43.8% when including BMD value. When stratified by age, patients aged 65 years or older were at a significantly (p<0.001) higher risk of suffering a hip or major osteoporotic fracture, highlighting the importance of including BMD measurements in this age group.

CONCLUSIONS

Our data support that DXA scanning of women with EBC should be performed to avoid overestimation of osteoporosis before AI treatment. It is particularly important in patients older than 65 years of age and when zoledronic acid is not an option.

Study of the variations of fall induced hip fracture risk between right and left femurs using CT-based FEA

Background

Hip fracture of elderly people—suffering from osteoporosis—is a severe public health concern, which can be reduced by providing a prior assessment of hip fracture risk. Image-based finite element analysis (FEA) has been considered an effective computational tool to assess the hip fracture risk. Considering the femoral neck region is the weakest, fracture risk indicators (FRI) are evaluated for both single-legged stance and sideways fall configurations and are compared between left and right femurs of each subject. Quantitative Computed Tomography (QCT) scan datasets of thirty anonymous patients’ left and right femora have been considered for the FE models, which have been simulated with an equal magnitude of load applied to the aforementioned configurations. The requirement of bilateral hip assessment in predicting the fracture risk has been explored in this study.

Results

Comparing the sideways fall and single-legged stance, the FRI varies by 64 to 74% at the superior aspects and by 14 to 19% at the inferior surfaces of both the femora. The results of this in vivo analysis clearly substantiate that the fracture is expected to initiate at the superior surface of femoral neck region if a patient falls from his/her standing height. The distributions of FRI between the femurs vary considerably, and the variability is significant at the superior aspects. The p value (= 0.02) obtained from paired sample t-Test yields p value ≤ 0.05, which shows the evidence of variability of the FRI distribution between left and right femurs. Moreover, the comparison of FRIs between the left and right femur of men and women shows that women are more susceptible to hip fracture than men.

Conclusions

The results and statistical variation clearly signify a need for bilateral hip scanning in predicting hip fracture risk, which is clinically conducted, at present, based on one hip chosen randomly and may lead to inaccurate fracture prediction. This study, although preliminary, may play a crucial role in assessing the hip fractures of the geriatric population and thereby, reducing the cost of treatment by taking predictive measure.

Low bone mineral density is not related to failure in femoral neck fracture patients treated with internal fixation

BACKGROUND AND PURPOSE

Internal fixation (IF) in femoral neck fractures has high reoperation rates and some predictors of failure are known, such as age, quality of reduction, and implant positioning. Finding new predictors of failure is an ongoing process, and in this study we evaluated the importance of low bone mineral density (BMD).

PATIENTS AND METHODS

140 consecutive patients (105 females, median age 80) treated with IF had a dual-energy X-ray absorptiometry (DXA) scan of the hip performed median 80 days after treatment. The patients' radiographs were evaluated for fracture displacement, implant positioning, and quality of reduction. From a questionnaire completed during admission, 2 variables for comorbidity and walking disability were chosen. Primary outcome was low hip BMD (amount of mineral matter per square centimeter of hip bone) compared to hip failure (resection, arthroplasty, or new hip fracture). A stratified Cox regression model on fracture displacement was applied and adjusted for age, sex, quality of reduction, implant positioning, comorbidity, and walking disability.

RESULTS

49 patients had a T-score below -2.5 (standard deviation from the young normal reference mean) and 70 patients had a failure. The failure rate after 2 years was 22% (95% CI: 12-39) for the undisplaced fractures and 66% (CI: 56-76) for the displaced fractures. Cox regression showed no association between low hip BMD and failure. For the covariates, only implant positioning showed an association with failure.

INTERPRETATION

We found no statistically significant association between low hip BMD and fixation failure in femoral neck fracture patients treated with IF.