Cortical bone structure of the proximal femur and incident fractures

Individual thigh muscle and proximal femoral features predict displacement in femoral neck Fractures: An AI-driven CT analysis

INTRODUCTION

Hip fractures, particularly among the elderly, impose a significant public health burden due to increased morbidity and mortality. Femoral neck fractures, commonly resulting from low-energy falls, can lead to severe complications such as avascular necrosis, and often necessitate total hip arthroplasty. This study harnesses AI to enhance musculoskeletal assessments by performing automatic muscle segmentation on whole thigh CT scans and detailed cortical measurements using the StradView program. The primary aim is to improve the prediction and prevention of severe femoral neck fractures, ultimately supporting more effective rehabilitation and treatment strategies.

METHODS

This study measured anatomical features from whole thigh CT scans of 60 femoral neck fracture patients. An AI-driven individual muscle segmentation model (a dice score of 0.84) segmented 27 muscles in the thigh region, to calculate muscle volumes. Proximal femoral bone parameters were measured using StradView, including average cortical thickness, inner density and FWHM at four regions. Correlation analysis evaluated relationships between muscle features, cortical parameters, and fracture displacement. Machine learning models (Random Forest, SVM and Multi-layer Perceptron) predicted displacement using these variables.

RESULTS

Correlation analysis showed significant associations between femoral neck displacement and trabecular density at the femoral neck/intertrochanter, as well as volumes of specific thigh muscles such as the Tensor fasciae latae. Machine learning models using a combined feature set of thigh muscle volumes and proximal femoral parameters performed best in predicting displacement, with the Random Forest model achieving an F1 score of 0.91 and SVM model 0.93.

CONCLUSION

Decreased volumes of the Tensor fasciae latae, Rectus femoris, and Semimembranosus muscles, coupled with reduced trabecular density at the femoral neck and intertrochanter, were significantly associated with increased fracture displacement. Notably, our SVM model-integrating both muscle and femoral features-achieved the highest predictive performance. These findings underscore the critical importance of muscle strength and bone density in rehabilitation planning and highlight the potential of AI-driven predictive models for improving clinical outcomes in femoral neck fractures.

Weaker subchondral bone and thinner articular cartilage of the knee are associated with elevated baseline fracture risk independently of osteoarthritis risk factors

Knee osteoarthritis involves damaged bones beneath joint surfaces but how current bone health predicts future disease state is unclear. We discovered higher osteoporotic fracture risk (FRAX) was linked to compromised knee bone quality and thinner cartilage. Integrating FRAX into osteoarthritis care could identify who may develop worse disease outcomes.

OBJECTIVES

To examine how well fracture risk predicts subchondral bone and cartilage morphometry independently of osteoarthritis (OA) clinical risk factors.

METHODS

Male and female participants in the Osteoarthritis Initiative (OAI) at visit 5 (36 months) were evaluated for fracture risk using FRAX and categorized into low-, moderate-, or high-risk groups. These groups were compared for bone marrow lesion (BML) size, number and effusion, subchondral bone structure, density, and cartilage morphometry in the most affected knee at either same time point, 1 or 2 years later, using general linear models. Sex interactions were examined in each case and probed if significant.

RESULTS

Among 1240 participants (58.8% female, age: 63.7 ± 8.8 years, and BMI: 30.1 ± 4.9 kg/m2), 20.32% had moderate or high FRAX and showed lower subchondral bone density (- 0.12 to - 0.25 g/cm2), less intact trabeculae, and thinner cartilage (- 0.14 to - 0.47 mm) compared to low FRAX (p < 0.05). Males showed larger positive FRAX correlations with bone density, and females had protective effects of FRAX against BML numbers, although the effects were small (sex interaction, p < 0.05). All FRAX models adjusting for OA risk factors yielded better model fit than OA risk factors alone. Having moderate/high versus low FRAX at baseline predicted a 1.36 (1.00, 1.86)-fold higher odds of reaching a Kellgren-Lawrence score of 3 or 4 within a year.

CONCLUSIONS

High FRAX predicts thinner cartilage and weaker subchondral bone within a year. Complementing standard OA clinical risk factors with FRAX calculation could help identify individuals likely to develop worse knee OA radiologic outcomes.

Prediction of the critical energy release rate for rat femoral cortical bone structure under different failure conditions

BACKGROUND AND OBJECTIVE

Critical energy release rate is a global fracture parameter that could be measured during the failing process, and its value may change under different failure conditions even in the same bone structure. The aim of this study was to propose an approach that combined the experimental test and finite element analysis to predict the critical energy release rates in the femoral cortical bone structures under compression and three-point bending loads.

METHODS

Three-point bending and compression experiments and the corresponding fracture simulations were performed on the rat femoral cortical bone structures. Different values of energy release rate were repeatedly assigned to the finite element models to perform fracture simulations, and then the load-displacement curves predicted in each simulation were compared with the experimental data to back-calculate the critical energy release rate.

RESULTS

The predicted data were similar to the experimental results when the calibrated energy release rate was suitable. The results showed that the cortical bone structure occurred shear open failure under compression load, and the predicted critical energy release rate was 0.12 N/mm. The same cortical bone structure occurred tensile open failure under three-point bending load, and the predicted critical energy release rate was 0.16 N/mm.

CONCLUSIONS

The critical energy release rates were different under various failure conditions in one cortical bone structure. A comprehensive analysis from the perspectives of material mechanical properties, failure mode, and damage fracture mechanism was conducted to reveal the reasons for the differences in the critical energy release rate in the cortical bone structure, which provided a theoretical basis for the measurement of the critical energy release rate and the accurate fracture simulation.

Relationship between site-specific bone mineral density in the proximal femur and instability of proximal femoral fractures: A retrospective study

BACKGROUND

Proximal femoral fractures can occur in patients with osteoporosis. However, the relationship between bone mineral density (BMD) of the proximal femur and fracture type and instability remains unclear. This study aimed to determine whether there is a relationship between the site-specific BMD of the proximal femur and the instability of proximal femoral fracture.

HYPOTHESIS

The instability of proximal femoral fractures is related to the site-specific BMD of the proximal femur.

PATIENTS AND METHODS

Using dual-energy X-ray absorptiometry (DEXA), the BMD on the non-fractured side was retrospectively examined in 252 women who underwent surgery for proximal femoral fracture at our hospital. The BMD was measured at three sites: the femoral neck (neck), trochanter (trochanter), and intertrochanteric region (inter). The BMD at several sites was compared between the femoral neck and trochanteric fractures. Femoral neck fractures were classified into the displaced and non-displaced types, and trochanteric fractures were classified into stable and unstable types. A comparative analysis was conducted for each proximal femur site and fracture type.

RESULTS

Both total and site-specific BMDs were lower in trochanteric fractures than in femoral neck fractures. No difference was observed between BMD and displaced or non-displaced femoral neck fractures. However, the BMD of the intertrochanteric region was lower in unstable trochanteric fractures (0.57±0.12g/cm2) than in stable trochanteric fractures (0.61±0.11g/cm2) [p<0.05].

DISCUSSION

Several factors, including the patient's age and the bone component of each region, may influence the lower BMD in trochanteric fractures. In trochanteric fractures, the site-specific BMD of the proximal femur may predict the type of fracture and the degree of instability, especially in those with low BMD at the intertrochanteric site. The study findings suggest that a decrease in the BMD of the intertrochanteric region of femoral trochanteric fractures, which is thought to be involved in instability, is associated with fracture type instability.

LEVEL OF EVIDENCE

III, retrospective study.

Criteria, Challenges, and Opportunities for Acellularized Allogeneic/Xenogeneic Bone Grafts in Bone Repairing

As bone grafts become more commonly needed by patients and as donors become scarcer, acellularized bone grafts (ABGs) are becoming more popular for restorative purposes. While autogeneic grafts are reliable as a gold standard, allogeneic and xenogeneic ABGs have been shown to be of particular interest due to the limited availability of autogeneic resources and reduced patient well-being in long-term surgeries. Because of the complete similarity of their structures with native bone, excellent mechanical properties, high biocompatibility, and similarities of biological behaviors (osteoinductive and osteoconductive) with local bones, successful outcomes of allogeneic and xenogeneic ABGs in both in vitro and in vivo research have raised hopes of repairing patients' bone injuries in clinical applications. However, clinical trials have been delayed due to a lack of standardized protocols pertaining to acellularization, cell seeding, maintenance, and diversity of ABG evaluation criteria. This study sought to uncover these factors by exploring the bone structures, ossification properties of ABGs, sources, benefits, and challenges of acellularization approaches (physical, chemical, and enzymatic), cell loading, and type of cells used and effects of each of the above items on the regenerative technologies. To gain a perspective on the repair and commercialization of products before implementing new research activities, this study describes the differences between ABGs created by various techniques and methods applied to them. With a comprehensive understanding of ABG behavior, future research focused on treating bone defects could provide a better way to combine the treatment approaches needed to treat bone defects.

Influence of comorbidity on postoperative course and mortality in patients with hip fracture

Introduction/Objective. Epidemiological research shows that we have a dramatic increase in the number of people with hip fractures, especially those over 65 years of age. The main objectives of this study are to assess the association between preoperative comorbidity and the risk of postoperative complications and mortality and postoperative worsening of comorbid conditions and their relationship to mortality within one year of hip fracture surgery. Methods. In the period from January 2018. until January 2020. in a retrospective study, at the Department of Orthopedic Surgery in Kosovska Mitrovica, we operated 64 patients with hip fractures. We monitored the number of comorbidities and their significance on the preoperative risk and the course of concomitant diseases in the postoperative period and one - year mortality from surgery, in patients with hip fractures. Results. We collected data on patients from the moment of admission to discharge from the hospital accompanied by medical histories, and after discharge after follow-up examinations, six months and one year from discharge. Of the total number of subjects, 23 (35.9%) had one or two comorbidities, most often of cardiac and neurological nature, in 25 patients (39.1%) we had three concomitant diseases, and in 11 (17.2%) four and more comorbidities. The mean age of the patients was 72.51 years (69-92 years). Conclusion. Approximately 45-60% of men and women who suffer a hip fracture have three or more comorbid states. In older people with hip fractures, the presence of three or more comorbidities is the strongest preoperative risk factor.

Differences in Hip Geometry Between Female Subjects With and Without Acute Hip Fracture: A Cross-Sectional Case-Control Study

BACKGROUND AND PURPOSE

Although it is widely recognized that hip BMD is reduced in patients with hip fracture, the differences in geometrical parameters such as cortical volume and thickness between subjects with and without hip fracture are less well known.

MATERIALS AND METHODS

Five hundred and sixty two community-dwelling elderly women with hip CT scans were included in this cross-sectional study, of whom 236 had an acute hip fracture. 326 age matched women without hip fracture served as controls. MIAF-Femur software was used for the measurement of the intact contralateral femur in patients with hip fracture and the left femur of the controls. Integral and cortical volumes (Vols) of the total hip (TH), femoral head (FH), femoral neck (FN), trochanter (TR) and intertrochanter (IT) were analyzed. In the FH and FN the volumes were further subdivided into superior anterior (SA) and posterior (SP) as well as inferior anterior (IA) and posterior (IP) quadrants. Cortical thickness (CortThick) was determined for all sub volumes of interest (VOIs) listed above.

RESULTS

The average age of the control and fracture groups was 71.7 and 72.0 years, respectively. The fracture patients had significantly lower CortThick and Vol of all VOIs except for TRVol. In the fracture patients, cortical thickness and volume at the FN were significantly lower in all quadrants except for cortical volume of quadrant SA (p= 0.635). Hip fracture patients had smaller integral FN volume and cross-sectional area (CSA) before and after adjustment of age, height and weight. With respect to hip fracture discrimination, cortical volume performed poorer than cortical thickness across the whole proximal femur. The ratio of Cort/TrabMass (RCTM), a measure of the internal distribution of bone, performed better than cortical thickness in discriminating hip fracture risk. The highest area under curve (AUC) value of 0.805 was obtained for the model that included THCortThick, FHVol, THRCTM and FNCSA.

CONCLUSION

There were substantial differences in total and cortical volume as well as cortical thickness between fractured and unfractured women across the proximal femur. A combination of geometric variables resulted in similar discrimination power for hip fracture risk as aBMD.