The 2nd Metacarpal Cortical Index as a Simple Screening Tool for Osteopenia

Prediction models incorporating second metacarpal cortical index for osteoporosis in rheumatoid arthritis: Externally validated machine learning models developed using data from the KURAMA cohort

OBJECTIVE

Osteoporosis and osteopenia are significant concerns in rheumatoid arthritis (RA), predisposing patients to fragility fractures. While dual-energy X-ray absorptiometry (DXA) is the gold standard for bone mineral density (BMD) assessment, simpler screening tools are needed. This study aims to assess the correlation between the second metacarpal cortical index (2MCI) and BMD in RA patients, and to evaluate machine learning (ML) models utilizing 2MCI and clinical parameters for predicting osteoporosis/osteopenia presence and BMD.

METHODS

Data from the KURAMA cohort (n = 302) and an external validation cohort (n = 32) were analyzed. BMD in the hip and forearm was obtained using DXA and 2MCI was calculated from plain hand X-ray. ML models were trained to predict osteoporosis/osteopenia presence and BMD using 2MCI and clinical variables and validated using external cohort.

RESULTS

2MCI correlated significantly with hip and forearm BMD. ML models incorporating 2MCI and other clinical parameters showed good performance in predicting osteoporosis/osteopenia presence and BMD. External validation demonstrated the generalizability of the models.

CONCLUSION

ML models utilizing 2MCI and clinical parameters show promise for osteoporosis screening in RA patients.

Gender and age differences in the associations between cortical thickness and hand osteoarthritis severity: data from the Osteoarthritis Initiative

OBJECTIVE

To evaluate gender differences in the association between metacarpal cortical thickness (Tcort)-a surrogate for bone density-and severity of radiographic hand osteoarthritis (HOA) in a longitudinal observational study.

METHOD

Hand radiographs of 3575 participants (2039 F/1536 M) from the Osteoarthritis Initiative were assessed at baseline and 48 months. A reader used a semi-automated software tool to calculate Tcort, a measurement of the cortical thickness, for metacarpals 2-4. Average Tcort at baseline and change in Tcort from baseline to 48 months was determined and stratified by gender and age for 7 5-year age groups. Spearman's rank correlation coefficients were calculated for the association of baseline Tcort and 2 measures of baseline HOA severity: the sum of Kellgren-Lawrence (KL) grade and total number of joints with radiographic HOA. Longitudinally, logistic regression was used to assess the relationship of Tcort loss to new finger joint radiographic HOA, increase in KL grades, and incident hand pain.

RESULTS

Male Tcort was higher than females. Significant correlations between Tcort and radiographic severity were noted for women but not men, with stronger associations among women >60 years (rho = -0.25; 95% confidence interval (CI) = -0.31 to -0.19). Statistically significant associations were seen between Tcort change and radiographic osteoarthritis change among women but not men, with substantial gender differences for Tcort change, particularly ages 50 to 70 years (p < 0.01; e.g., Tcort change ages 55 to <60: males = -0.182 (0.118), females = -0.219 (0.124)).

CONCLUSION

We found significant HOA-related gender differences in Tcort, suggesting the involvement of female bone loss during and after menopause.

The Orthopedic Upper Extremity Surgeon's Role in the Diagnosis and Treatment of Osteoporosis: Making Use of Opportunistic Imaging

Osteoporosis is an underdiagnosed and undertreated public health issue that contributes to a high financial burden on the healthcare system and imposes significant morbidity and mortality on the patient population. Upper extremity orthopedic surgeons are in a unique position to diagnose osteoporosis prior to patients suffering a fragility fracture by using imaging that they already obtain in their current workflow. The use of X-rays and CT scans can effectively diagnose osteoporosis with high sensitivity and specificity. By incorporating these diagnostic methods into standard practice, upper extremity orthopedic surgeons can play a critical role in the early diagnosis and treatment of osteoporosis. This can prevent severe fractures, improve patient outcomes, and reduce the overall healthcare burden by initiating timely treatment and patient education. This review emphasizes the importance of opportunistic imaging in enhancing osteoporosis management and suggests that upper extremity surgeons can significantly and effectively contribute to primary and secondary fracture prevention.

Scaphoid Fractures in Adults Aged 50 Years or Older: Epidemiology and Association With Osteopenia and Nonunion

BACKGROUND

Scaphoid fractures are less commonly reported in adults older than 50 years. The association between bone density and outcomes following scaphoid fractures has not been explored in this patient population. The second metacarpal cortical percentage (2MCP) has been shown to predict low bone density. The purpose of this study is to describe the epidemiology and radiographic characteristics associated with scaphoid fractures in adults older than 50 years, determine the prevalence of osteopenia defined by 2MCP, and evaluate the characteristics associated with scaphoid nonunion in this population. We hypothesized that osteopenia defined by 2MCP would be common in this patient population and associated with scaphoid nonunion.

METHODS

Patients older than 50 years with an acute, closed scaphoid fracture were identified. Demographic data, radiographic characteristics, and outcome data were collected. The 2MCP was measured using standard hand radiographs.

RESULTS

A total of 111 patients were identified. Most fractures were nondisplaced and occurred in women via low-energy mechanism. Fifty-six patients (50.5%) had osteopenia defined by a 2MCP less than 60%. Nondisplaced fractures achieved union faster than displaced fractures (P < .05). Displaced, unstable fractures were statistically associated with nonunion (P < .001). 2MCP did not correlate with nonunion.

CONCLUSIONS

In adults older than 50 years, scaphoid fractures may represent a fragility fracture cohort given they occur more frequently in female patients via low-energy mechanisms and over half of the cohort had osteopenia defined by a 2MCP less than 60%. Displaced and unstable fractures were statistically more likely to go on to nonunion. Nonunion was not found to be associated with osteopenia.

Opportunistic hand radiographs to screen for low forearm bone mineral density: a prospective and retrospective cohort study

BACKGROUND

Low bone mineral density affects 53% of women over age 65 in the US, yet many are unaware and remain untreated. Underdiagnosis of forearm osteoporosis and related fragility fractures represent missed warning signs of more deadly, future fractures. This study aimed to determine if hand radiographs could serve as early, simple screening tools for predicting low forearm bone mineral density (BMD).

METHODS

We evaluated posterior-anterior (PA) hand radiographs (x-rays) and Dual-energy X-ray absorptiometry (DXA) scans of 43 participants. The ratio of the intramedullary cavity to total cortical diameter of the second metacarpal (second metacarpal cortical percentage (2MCP)) was used as a potential diagnostic marker. Mixed-effects linear regression was performed to determine correlation of 2MCP with BMD from various anatomic regions. Repeated measures ANOVAs were used to compare BMD across sites. An optimal 2MCP cutoff for predicting forearm osteopenia and osteoporosis was found using Receiver Operating Curves.

RESULTS

2MCP is directly correlated with BMD in the forearm. The optimal 2MCP of 48.3% had 80% sensitivity for detecting osteoporosis of the 1/3 distal forearm. An 2MCP cutoff of 50.8% had 84% sensitivity to detect osteoporosis of the most distal forearm. Both 2MCP cutoffs were more sensitive at predicting forearm osteoporosis than femoral neck T-scores.

CONCLUSIONS

These findings support the expansion of osteoporosis screening to include low-cost hand x-rays, aiming to increase diagnosis and treatment of low forearm BMD and fractures. Proposed next steps include confirming the optimal 2MCP cutoff at scale and integrating automatic 2MCP measurements into PAC systems.

A Healed Intertrochanteric Femur Fracture, Shoulder, and Rib Fractures in an Ancient Nubian Female: An Osteoarchaeological Perspective

This report is a case of a healed proximal intertrochanteric femur fracture nonunion in an ancient Nubian adult female, approximately 58 years old at the time of death, from the Tombos archaeological site in present day northern Sudan. Tombos was founded as an Egyptian colonial town during the New Kingdom Period (14001070 BC). The individual was radiocarbon dated to 1114-910 BC and also exhibited healed fractures of the left proximal humerus and ribs. There was shortening and mild atrophy of the right femur compared to the left; radiographs demonstrated a varus deformity of the proximal femur with associated retroversion. Bone density analysis revealed that the tissue mineral density z-score for this individual was -0.798, with the z-score for Tombos females 15-24 years old being 0.396, or a total difference of 1.194. This indicates that the individual was osteopenic but not osteoporotic prior to demise. This is an important case as it occurred approximately 3000 years ago and is the oldest known reported case of a healed intertrochanteric hip fracture in the archaeological literature. Archaeological cases of intertrochanteric hip fractures are rare, with none previously reported from the BC era. The timing of these multiple fractures is unknown, but all healed before the demise of the individual. Thus, there must have been considerable care afforded to such an individual to minimize the morbidities associated with nonoperative care of such a fracture. If all these fractures occurred at the same time due to a traumatic, accidental injury, the Modified Injury Severity Score (MISS) would be 25. Modern day trauma resuscitation and orthopaedic care gives an estimated mortality for such a MISS score of 28% for those <50 years old. It is likely that this individual's high socioeconomic status allowed for intensive nursing care which likely decreased the morality risk.

Sex and External Size Specific Limitations in Assessing Bone Health From Adult Hand Radiographs

Morphological parameters measured for the second metacarpal from hand radiographs are used clinically for assessing bone health during growth and aging. Understanding how these morphological parameters relate to metacarpal strength and strength at other anatomical sites is critical for providing informed decision-making regarding treatment strategies and effectiveness. The goals of this study were to evaluate the extent to which 11 morphological parameters, nine of which were measured from hand radiographs, relate to experimentally measured whole-bone strength assessed at multiple anatomical sites and to test whether these associations differed between men and women. Bone morphology and strength were assessed for the second and third metacarpals, radial diaphysis, femoral diaphysis, and proximal femur for 28 white male donors (18-89 years old) and 35 white female donors (36-89+ years old). The only morphological parameter to show a significant correlation with strength without a sex-specific effect was cortical area. Dimensionless morphological parameters derived from hand radiographs correlated significantly with strength for females, but few did for males. Males and females showed a significant association between the circularity of the metacarpal cross-section and the outer width measured in the mediolateral direction. This cross-sectional shape variation contributed to systematic bias in estimating strength using cortical area and assuming a circular cross-section. This was confirmed by the observation that use of elliptical formulas reduced the systematic bias associated with using circular approximations for morphology. Thus, cortical area was the best predictor of strength without a sex-specific difference in the correlation but was not without limitations owing to out-of-plane shape variations. The dependence of cross-sectional shape on the outer bone width measured from a hand radiograph may provide a way to further improve bone health assessments and informed decision making for optimizing strength-building and fracture-prevention treatment strategies. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Machine Learning for Opportunistic Screening for Osteoporosis from CT Scans of the Wrist and Forearm

Background: We investigated whether opportunistic screening for osteoporosis can be done from computed tomography (CT) scans of the wrist/forearm using machine learning. Methods: A retrospective study of 196 patients aged 50 years or greater who underwent CT scans of the wrist/forearm and dual-energy X-ray absorptiometry (DEXA) scans within 12 months of each other was performed. Volumetric segmentation of the forearm, carpal, and metacarpal bones was performed to obtain the mean CT attenuation of each bone. The correlations of the CT attenuations of each of the wrist/forearm bones and their correlations to the DEXA measurements were calculated. The study was divided into training/validation (n = 96) and test (n = 100) datasets. The performance of multivariable support vector machines (SVMs) was evaluated in the test dataset and compared to the CT attenuation of the distal third of the radial shaft (radius 33%). Results: There were positive correlations between each of the CT attenuations of the wrist/forearm bones, and with DEXA measurements. A threshold hamate CT attenuation of 170.2 Hounsfield units had a sensitivity of 69.2% and a specificity of 77.1% for identifying patients with osteoporosis. The radial-basis-function (RBF) kernel SVM (AUC = 0.818) was the best for predicting osteoporosis with a higher AUC than other models and better than the radius 33% (AUC = 0.576) (p = 0.020). Conclusions: Opportunistic screening for osteoporosis could be performed using CT scans of the wrist/forearm. Multivariable machine learning techniques, such as SVM with RBF kernels, that use data from multiple bones were more accurate than using the CT attenuation of a single bone.