Evaluation of femoral head bone quality by Hounsfield units: a comparison with dual-energy X-ray absorptiometry

Systemic Osteoporosis and Osteopenia Among Periprosthetic Fractures After Total Hip Arthroplasty

BACKGROUND

Most periprosthetic fractures following total hip arthroplasty (THA) are fragility fractures that qualify patients for osteoporosis diagnoses. However, it remains unknown how many patients were diagnosed who had osteoporosis before injury or received the proper evaluation, diagnosis, and treatment after injury.

METHODS

We identified 171 Vancouver B2 (109) and B3 (62) periprosthetic femur fractures treated with a modular fluted tapered stem from 2000 to 2018 at one institution. The mean patient age was 75 years (range, 35 to 94), 50% were women, and the mean BMI was 29 (range, 17 to 60). We identified patients who had osteoporosis or osteopenia diagnoses, a fracture risk assessment tool (FRAX), bone mineral density (BMD) testing, an endocrinology consult, and osteoporosis medications. Age-appropriate BMD testing was defined as no later than one year after the recommended ages of 65 (women) or 70 years (men). The mean follow-up was 11 years (range, 4 to 21).

RESULTS

Falls from standing height caused 94% of fractures and thus, by definition, qualified as osteoporosis-defining events. The prevalence of osteoporosis diagnosis increased from 20% before periprosthetic fracture to 39% after (P < 0.001). The prevalence of osteopenia diagnosis increased from 13% before the fracture to 24% after (P < 0.001). The prevalence of either diagnosis increased from 24% before fracture to 44% after (P < 0.001). No patients had documented FRAX scores before fracture, and only 2% had scores after. The prevalence of BMD testing was 21% before fracture and 22% after (P = 0.88). By the end of the final follow-up, only 16% had received age-appropriate BMD testing. The proportion of patients who had endocrinology consults increased from 6% before the fracture to 25% after (P < 0.001). The proportion on bisphosphonate therapy was 19% before fracture and 25% after (P = 0.08).

CONCLUSIONS

Although most periprosthetic fractures following THA are fragility fractures that qualify patients for osteoporosis diagnoses, there remain major gaps in diagnosis, screening, endocrinology follow-up, and treatment. Like non-arthroplasty fragility fractures, a systematic approach is needed after periprosthetic fractures.

Comparative Analysis of the 3 Cervical Vertebral Bone Quality (C-VBQ) Score Methodologies and Their Correlations to the Lumbar Vertebral Bone Quality (VBQ) Score

OBJECTIVE

Common complications after spinal fusion, such as pseudoarthrosis, cage subsidence, or instrumentation failure, are affected by patients' bone quality. The cervical-vertebral bone quality (C-VBQ) score, a magnetic resonance imaging (MRI)-based adaption of the lumbar vertebral bone quality (VBQ) score, was developed by 3 separate research groups simultaneously to evaluate bone quality in cervical spinal fusion patients. We present the first analysis comparing these scoring methods to the well-validated VBQ score.

METHODS

A retrospective analysis of data for consecutive patients who underwent spine surgery at a single institution was completed. The VBQ score was calculated using the Ehresman et al.

METHOD

The C-VBQ scores, named according to placement of the region of interest within the cerebral spinal fluid, were calculated separately using the methods of Soliman et al. (C2-VBQ), Razzouk et al. (C5-VBQ), and Huang et al. (T1-VBQ). Linear regression models were utilized to evaluate correlations to the VBQ score.

RESULTS

A total of 105 patients were identified (mean age, 57.0 ± 11.9 years; women, 50.5%). Mean scores were C2-VBQ, 2.37 ± 0.55; C5-VBQ, 2.36 ± 0.61; and T1-VBQ, 2.64 ± 0.68. The C-VBQ scores for the C2 level were significantly higher than those for the C3-C6 levels (3.18 ± 0.96 vs. 2.63 ± 0.77, P < 0.001), whereas the C7 level was found to have significantly lower C-VBQ scores (2.42 ± 0.78 vs. 2.63 ± 0.77, P = 0.04). The C2-VBQ (r = 0.63) score had the strongest correlation to the VBQ score, compared to C5-VBQ (r = 0.41) and T1-VBQ (r = 0.43) (P < 0.001).

CONCLUSIONS

This study demonstrates that the C2-VBQ had the strongest correlation to the lumbar VBQ score among all C-VBQ scores.

Measurement of Hounsfield units on proximal femur computed tomography for predicting regional osteoporosis

OBJECTIVE

This study was designed to investigate the use of proximal femoral Hounsfield units (HU) in conventional abdominal and pelvic computed tomography (CT) to predict hip osteoporosis by coupling with data from quantitative CT (QCT).

METHODS

In this study, 315 patients who underwent routine abdominal and pelvic CT with the proximal femur included in the scanning range were also subjected to QCT of the proximal femur. Pearson correlation test was performed to analyze the correlations of the femoral head, femoral neck, proximal femur, and femoral trochanter CT HU with the femoral neck, femoral trochanter, and intertrochanteric femur bone mineral density (BMD) values from QCT. The diagnostic performance of CT HU measurement of the proximal femur for osteoporosis was analyzed using receiver operating characteristic (ROC) curves.

RESULTS

The CT HU of the proximal femur showed the highest correlation with the BMD value of the hip (r = 0.826; p < 0.01). The mean CT HU of the proximal femur differed significantly (all p < 0.01) for the three QCT-defined BMD categories of osteoporosis (192.23 HU vs. 188.71), of osteopenia (247.86 HU vs. 248.36 HU), and of normal individuals (308.13 HU vs. 310.41 HU) in left and right sides, respectively. In the ROC curve analysis, the area under the ROC curve values to predict osteoporosis in the left and right proximal femurs were 0.942 and 0.941, respectively.

CONCLUSION

The CT HU of the proximal femur was significantly associated with the BMD value of the hip measured by QCT. The CT HU of the proximal femur is highly effective in diagnosing osteoporosis and could be used for hip osteoporosis screening.

Hounsfield units predicts the occurrence but not the patterns of proximal humerus fracture in the elderly patients

BACKGROUND

Increased incidence of fragility fractures of the proximal humerus has been reported. Proximal humerus Hounsfield unit (HU) measurements based on computed tomography (CT) scans of the shoulder can be used to evaluate bone mineral density (BMD). It is unknown whether HU values can predict the risk of proximal humerus osteoporotic fracture and /or fracture patterns. Therefore, the objectives of this study were to identify whether the HU value is associated with proximal humeral osteoporotic fracture risk, and whether or not it has an impact on the complexity of the fracture.

METHODS

We identified 60 + years old patients' CT scans between 2019 and 2021 according to the inclusion and exclusion criteria. All patients were divided into two groups based on the presence or lack of a fracture in the proximal humerus, meanwhile, patients with fractures were stratified into simple and comminuted fractures based on the Neer classification. HU values were calculated within the proximal humerus and compared between groups using the Student t-test, and receiver operating characteristic (ROC) curve analysis was used to determine the ability of HU values to predict fracture.

RESULTS

A total of 138 patients with proximal humerus fracture (PHF) including 62 simple PHFs and 76 complex PHFs and 138 non-fracture patients were enrolled in the study. The HU values decreased as age increased among all patients. Both male and female patients with PHF had significantly lower HU values compared with non-fracture patients, the area under the curve (AUC) of the ROC curve for males and females was 0.8 and 0.723 respectively. Nevertheless, no significant differences were found between simple and complex fractures of the proximal humerus in the HU values.

CONCLUSION

Decreasing HU values on CT may be an early warning sign of fracture potential, however, it was not a predictive factor for comminuted fracture of the proximal humerus.

Evaluation of femoral head bone quality by Hounsfield units: A predictor of implant failure for intertrochanteric fractures after intramedullary nail fixation

Purpose

The aim of present study is to evaluate the femoral head bone quality by Hounsfield units and its relationship to the occurrence of implant failure for intertrochanteric fractures after intramedullary nail fixation.

Methods

This retrospective study assessed 160 intertrochanteric fractures treated with intramedullary fixation. Patients with and without implant failure were divided into failure and control groups, respectively. The demographic information, femoral head Hounsfield unit (HU) value, the reduction quality, status of posteromedial support and position of the screw/blade were collected and compared. The logistic regression analyses were performed to evaluate risk factors of implant failure in intertrochanteric fractures after intramedullary nail fixation.

Results

Of the patients, 15 (9.38%) suffered from implant failure after intramedullary fixation. The mean HU value of femoral head was much lower in the failure group than the control group (133.25 ± 34.10 vs. 166.12 ± 42.68, p = 0.004). And the univariate analyses showed that A3 fracture and poor reduction quality were associated with implant failure (p < 0.05). After adjustment for confounding variables, the multivariable logistic regression analyzes showed that femoral head HU value (odds ratio [OR], 0.972; 95% CI, 0.952-0.993; p = 0.008) and poor reduction quality (OR, 7.614; 95% CI, 1.390-41.717; p = 0.019) were independent influencing factors for implant failure.

Conclusion

The femoral head HU value was significantly correlated with the incidence of implant failure and can be used as an independent factor to predict implant failure for intertrochanteric fractures after intramedullary fixation.

Screening for osteoporosis using L1 vertebral density on abdominal CT in an Australian population

AIM

To assess the utility of osteoporosis screening using abdominal computed tomography (CT) versus dual-energy X-ray absorptiometry (DXA) T-scores as the reference.

MATERIALS AND METHODS

Patients ≥30 years undergoing abdominal CT and DXA within 12 months were assessed retrospectively. Bone mineral density (BMD) was measured using axial CT attenuation at L1, correlating with DXA T-scores. Sensitivity, specificity, area under the curve (AUC), and odds ratio (OR) were calculated.

RESULTS

The study cohort comprised 407 CT-DXA pairs (58.2% women). The prevalence of osteoporosis was 11.8%. L1 density and T-score were significantly correlated in both women (r=0.35, p<0.001) and men (r=0.15, p=0.04). The AUC to distinguish osteoporosis from osteopenia and normal BMD was 0.64 (95% CI: 0.56-0.71). In women, a threshold of 190 HU detected T-scores ≤ -2.5 with a negative predictive value (NPV) of 94.4% (OR=4.4, p<0.01). In the entire cohort, a threshold of 180 HU detected T-scores ≤ -2.5 with a NPV of 96.2% (OR=4.7, p<0.01).

CONCLUSIONS

CT L1 attenuation correlates with L1 DXA T-scores. Density values < 190 and 180 HU increased the probability of an osteoporosis diagnosis in Australian women and the overall cohort, respectively. Opportunistic screening for osteoporosis using abdominal CT is feasible, enabling identification of at-risk subjects for formal DXA imaging, thereby improving treatment initiation and reducing fracture risk.