A Spatio-Temporal Ageing Atlas of the Proximal Femur

Quantitating Age-Related BMD Textural Variation from DXA Region-Free-Analysis: A Study of Hip Fracture Prediction in Three Cohorts

The risk of osteoporotic fracture is inversely related to bone mineral density (BMD), but how spatial BMD pattern influences fracture risk remains incompletely understood. This study used a pixel-level spatiotemporal atlas of proximal femoral BMD in 13,338 white European women (age 20-97 years) to quantitate age-related texture variation in BMD maps and generate a "reference" map of bone aging. We introduce a new index, called Densitometric Bone Age (DBA), as the age at which an individual site-specific BMD map (the proximal femur is studied here) best matches the median aging trajectory at that site in terms of the root mean squared error (RMSE). The ability of DBA to predict incident hip fracture and hip fracture pattern over 5 years following baseline BMD was compared against conventional region-based BMD analysis in a subset of 11,899 women (age 45-97 years), for which follow-up fracture records exist. There were 208 subsequent incident hip fractures in the study populations (138 femoral necks [FNs], 52 trochanteric [TR], 18 sites unspecified). DBA had modestly better performance compared to the conventional FN-BMD, TR-BMD, and total hip (TOT)-BMD in identifying hip fractures measured as the area under the curve (AUC) using receiver operating characteristics (ROC) curve analysis by 2% (95% confidence interval [CI], -0.5% to 3.5%), 3% (95% CI, 1.0% to 4.0%), and 1% (95% CI, 0.4% to 1.6%), respectively. Compared to FN-BMD T-score, DBA improved the ROC-AUC for predicting TR fractures by ~5% (95% CI, 1.1% to 9.8%) with similar performance in identifying FN fractures. Compared to TR-BMD T-score, DBA improved the ROC-AUC for the prediction of FN fractures by ~3% (95% CI, 1.1% to 4.9%), with similar performance in identifying TR fractures. Our findings suggest that DBA may provide a spatially sensitive measure of proximal femoral fragility that is not captured by FN-BMD or TR-BMD alone. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Bone Radiomics Score Derived From DXA Hip Images Enhances Hip Fracture Prediction in Older Women

Dual-energy X-ray absorptiometry (DXA)-based bone mineral density testing is standard to diagnose osteoporosis to detect individuals at high risk of fracture. A radiomics approach to extract quantifiable texture features from DXA hip images may improve hip fracture prediction without additional costs. Here, we investigated whether bone radiomics scores from DXA hip images could improve hip fracture prediction in a community-based cohort of older women. The derivation set (143 women who sustained hip fracture [mean age 73 years, time to fracture median 2.1 years] versus 290 age-matched women [mean age 73 years] who did not sustain hip fracture during follow-up [median 5.5 years]) were split into the train set (75%) and the test set (25% hold-out set). Among various models using 14 selected features out of 300 texture features mined from DXA hip images in the train set, random forest model was selected as the best model to build a bone radiomics score (range 0 to 100) based on the performance in the test set. In a community-based cohort (2029 women, mean age 71 years) as the clinical validation set, the bone radiomics score was calculated using a model fitted in the train set. A total of 34 participants (1.7%) sustained hip fracture during median follow-up of 5.4 years (mean bone radiomics score 40 ± 16 versus 28 ± 12 in non-fractured, p < 0.001). A one-point bone radiomics score increment was associated with a 4% elevated risk of incident hip fracture (adjusted hazard ratio [aHR] = 1.04, p = 0.001) after adjustment for age, body mass index (BMI), previous history of fracture, and femoral neck T-score, with improved model fit when added to covariates (likelihood ratio chi-square 10.74, p = 0.001). The association between bone radiomics score with incident hip fracture remained robust (aHR = 1.06, p < 0.001) after adjustment for FRAX hip fracture probability. Bone radiomics scores estimated from texture features of DXA hip images have the potential to improve hip fracture prediction. © 2021 American Society for Bone and Mineral Research (ASBMR).

Influence of Femoral Component Design on Proximal Femoral Bone Mass After Total Hip Replacement: A Randomized Controlled Trial

BACKGROUND

In this randomized controlled trial (RCT), we compared bone remodeling and bone turnover between 2 total hip arthroplasty implants-the short, proximally porous-coated Tri-Lock Bone-Preservation Stem and a conventional, fully-coated Corail prosthesis-over a 2-year postoperative period.

METHODS

Forty-six participants received the Tri-Lock prosthesis and 40 received the Corail prosthesis. At baseline, the 2 groups had similar demographics, proximal femoral bone mineral density (BMD), bone turnover markers, radiographic canal flare index, and patient-reported outcome measure (PROM) scores. Outcomes were measured at weeks 26, 52, and 104.

RESULTS

Loss of periprosthetic bone, measured by high-sensitivity dual x-ray absorptiometry region-free analysis (DXA-RFA), was identified at the calcar and proximal-lateral aspect of the femur in both prosthesis groups (p < 0.05). However, the conventional prosthesis was associated with a smaller reduction in BMD compared with the bone-preservation prosthesis (p < 0.001). This effect was most prominent in the region of the femoral calcar and greater trochanter. A small gain in BMD was also identified in some areas, and this gain was greater with the conventional than the bone-preservation prosthesis (p < 0.001). The 2 groups had similar changes in bone turnover markers and improvement in PROM scores over the study period (p > 0.05). The adverse-event rate was also similar between the groups (p > 0.05).

CONCLUSIONS

This RCT shows that prostheses intended to preserve proximal femoral bone do not necessarily perform better in this regard than conventional cementless designs. DXA-RFA is a sensitive tool for detecting spatially complex patterns of periprosthetic bone remodeling.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.