Distinctive Geometrical Traits of Proximal Femur Fractures-Original Article and Review of Literature

Background and Objectives: The incidence of proximal femoral fractures is escalating rapidly, generating a significant challenge for healthcare systems globally and, carrying serious social and economic implications. The primarily object of this study was to discover potential distinguishing factors between fractures occurring in the femoral neck and trochanteric region. Materials and Methods: We performed a prospective cohort study of the radiographic images of 70 people over 65 years of age who were admitted to the orthopedic department with hip fracture and who fulfilled our eligibility criteria. Neck Length (NL), Offset Lenth (OL), Hip Axis Length (HAL), Neck Shaft Angle (NSA), Wiberg Angle (WA), Acetabular Angle (AA), Femoral Neck Diameter (FND), Femoral Head Diameter (FHD), Femoral Shaft Diameter (FSD), Femoral Canal Diameter (FCD) and Tonnis classification were recorded. For the comparison of the categorical variables, Pearson's χ2 criterion was used, while Student's t-test was applied for the comparison of means of quantitative variables across fracture types. Results: There were no statistically significant variances observed while comparing the selected geometric parameters of the proximal femur with the type of fracture. This finding was reaffirmed in relation to age, gender, and Tonnis classification. However, a moderate correlation was noted, revealing comparatively reduced values of HAL, FHD, and FND in women as opposed to men. Conclusions: The inability of our research to establish the differentiative geometric factors between femoral neck and trochanteric fractures underscores the need for further investigations, which would take into consideration the intrinsic characteristics of the proximal femur.

Multi-view information fusion using multi-view variational autoencoder to predict proximal femoral fracture load

Background

Hip fracture occurs when an applied force exceeds the force that the proximal femur can support (the fracture load or "strength") and can have devastating consequences with poor functional outcomes. Proximal femoral strengths for specific loading conditions can be computed by subject-specific finite element analysis (FEA) using quantitative computerized tomography (QCT) images. However, the radiation and availability of QCT limit its clinical usability. Alternative low-dose and widely available measurements, such as dual energy X-ray absorptiometry (DXA) and genetic factors, would be preferable for bone strength assessment. The aim of this paper is to design a deep learning-based model to predict proximal femoral strength using multi-view information fusion.

Results

We developed new models using multi-view variational autoencoder (MVAE) for feature representation learning and a product of expert (PoE) model for multi-view information fusion. We applied the proposed models to an in-house Louisiana Osteoporosis Study (LOS) cohort with 931 male subjects, including 345 African Americans and 586 Caucasians. We performed genome-wide association studies (GWAS) to select 256 genetic variants with the lowest p-values for each proximal femoral strength and integrated whole genome sequence (WGS) features and DXA-derived imaging features to predict proximal femoral strength. The best prediction model for fall fracture load was acquired by integrating WGS features and DXA-derived imaging features. The designed models achieved the mean absolute percentage error of 18.04%, 6.84% and 7.95% for predicting proximal femoral fracture loads using linear models of fall loading, nonlinear models of fall loading, and nonlinear models of stance loading, respectively.

Conclusion

The proposed models are capable of predicting proximal femoral strength using WGS features and DXA-derived imaging features. Though this tool is not a substitute for predicting FEA using QCT images, it would make improved assessment of hip fracture risk more widely available while avoiding the increased radiation exposure from QCT.

[Long-term effectiveness of uncemented allograft-prosthesis composite for reconstruction of bone defects after proximal femur tumor resection]

Objective

To investigate the long-term effectiveness of uncemented allograft-prosthesis composite (APC) for reconstruction of bone defects after proximal femur tumor resection.

Methods

Between June 2007 and March 2014, 21 patients who underwent uncemented APC reconstruction of proximal femur after tumor resection were retrospectively evaluated. There were 9 males and 12 females with an average age of 33.2 years (range, 19-54 years). There were 9 cases of giant cell tumor of bone, 5 cases of osteosarcoma, 4 cases of osteoblastic osteosarcoma, 2 cases of chondrosarcoma, and 1 case of undifferentiated pleomorphic sarcoma. Thirteen cases of benign bone tumors were all classified as stage 3 by Enneking staging; and 8 cases of malignant bone tumors were classified as grade ⅡB in 7 cases and grade ⅡA in 1 case according to the American Joint Committee on Cancer (AJCC) staging system. Among them, 7 patients underwent reoperation after recurrence, and the rest were primary operations; 8 patients presented with pathological fractures. The preoperative Harris hip score (HHS) and American Musculoskeletal Tumor Society (MSTS) score was 40 (30, 49) and 9.1±3.5, respectively. The length of osteotomy was 80-154 mm, with an average of 110 mm. At 1 year after operation and last follow-up, HHS and MSTS scores were utilized to evaluate the function of hip joint; the gluteus medius strength score was used to evaluation of the hip abduction function. Image examinations were taken at 1, 3, 6, 9, and 12 months after operation and every year thereafter to assess the union of allograft-host bone interfaces. Intra- and post-operative complications were also recorded.

Results

All patients were followed up 84-163 months (mean, 123.5 months). At 1 year after operation and last follow-up, the HHS and MSTS scores significantly improved when compared with the preoperative scores ( P<0.05). However, there was no significant difference in the HHS score, MSTS score, and gluteus medius strength score between the two time points after operation ( P>0.05). Image examination showed that all allograft-host bone interfaces achieved union after 5-10 months (mean, 7.6 months). At last follow-up, all patients had bone resorption, including 11 severe cases, 4 moderate cases, and 6 mild cases; the bone resorption sites included Gruen 1, 2, and 7 regions. Complications included 10 fractures and 1 prosthetic fracture. Local recurrence occurred in 3 patients and pulmonary metastasis in 3 patients.

Conclusion

Uncemented APC is a reliable method for the reconstruction of bone defects after proximal femur tumor resection. It has the good long-term effectiveness and possesses obvious advantages in the union at the bone-bone surface.

Ewing's sarcoma of proximal femur: case report of extreme osteotomy with 3D-printed prosthesis for the reconstruction

Background: Resection and reconstruction of malignant bone tumors at the proximal femur in adolescent patients has remained a clinical challenge. Considering the growth and development requirements of adolescents, there is no unified standard for the reconstruction of bone defects at the proximal femur. Here, we report a case of 3D-printed titanium alloy customized prosthesis for the construction of proximal femoral bone defects in an adolescent patient with Ewing's sarcoma of the proximal femur. Case presentation: A 7-year-old female patient presented to a local hospital with left hip pain, and was diagnosed with Ewing's sarcoma on the proximal left femur. The patient received two courses of neoadjuvant chemotherapy before surgery according to the standard protocol. Considering growth and development problems associated with adolescents, we adopted a customized 3D-printed prosthesis of proximal femur for preservation of the femoral head and part of the femoral neck in the affected limb. Clinical outcomes, recorded after 12 months of follow-up, revealed excellent functional recovery and satisfactory functional scores of the affected limb, with no immediate complications. Conclusion: 3D-printed prosthesis is a feasible method for preserving femoral head and reconstruction of bone defects in adolescents' proximal femur.

Analysis of implants for metastatic bone tumors of the proximal femur: A retrospective study

AIM

To investigate the relationship between surgical techniques used in our hospital to treat metastatic bone tumors of the proximal femur and activity level and prognosis of patients and whether the location of the tumor is considered when selecting surgical techniques.

METHODS

We retrospectively reviewed 82 patients with metastatic bone tumors of the proximal femur who underwent intramedullary nail fixation (IMN), bipolar hip arthroplasty (BHP) or modular megaprosthesis (MMP) in our hospital from 2007 to 2020. We measured the distance from the center of femoral head to the proximal (x) and distal (y) end of the of tumor, using preoperative computed tomography images to determine the location of metastasis. We also measured revised Katagiri score at the time of fracture, postoperative ISOLS/MSTS (functional outcome) scores, and overall survival.

RESULTS

The value of x was significantly different among the three groups. The value of y showed a significant difference between the IMN and BHP groups and the BHP and MMP groups. The functional outcome score was significantly lower in the IMN group. The survival rate of the patient tended to be higher in the BHP and MMP groups than in the IMN group 1 year postoperatively.

CONCLUSION

IMN was favored when the distance from the center of femoral head to the proximal end of the tumor was ≥15 mm. In the case of prosthetic replacement, BHP was chosen if the distance from the center of femoral head to the distal end of the tumor was ≤70 mm. BHP and MMP were preferred over IMN functionally.

Development and validation of an open-source tool for opportunistic screening of osteoporosis from hip CT images

Aims

This study aimed to develop and validate a fully automated system that quantifies proximal femoral bone mineral density (BMD) from CT images.

Methods

The study analyzed 978 pairs of hip CT and dual-energy X-ray absorptiometry (DXA) measurements of the proximal femur (DXA-BMD) collected from three institutions. From the CT images, the femur and a calibration phantom were automatically segmented using previously trained deep-learning models. The Hounsfield units of each voxel were converted into density (mg/cm3). Then, a deep-learning model trained by manual landmark selection of 315 cases was developed to select the landmarks at the proximal femur to rotate the CT volume to the neutral position. Finally, the CT volume of the femur was projected onto the coronal plane, and the areal BMD of the proximal femur (CT-aBMD) was quantified. CT-aBMD correlated to DXA-BMD, and a receiver operating characteristic (ROC) analysis quantified the accuracy in diagnosing osteoporosis.

Results

CT-aBMD was successfully measured in 976/978 hips (99.8%). A significant correlation was found between CT-aBMD and DXA-BMD (r = 0.941; p < 0.001). In the ROC analysis, the area under the curve to diagnose osteoporosis was 0.976. The diagnostic sensitivity and specificity were 88.9% and 96%, respectively, with the cutoff set at 0.625 g/cm2.

Conclusion

Accurate DXA-BMD measurements and diagnosis of osteoporosis were performed from CT images using the system developed herein. As the models are open-source, clinicians can use the proposed system to screen osteoporosis and determine the surgical strategy for hip surgery.

Postoperative Fracture Risk in Giant Cell Tumor: A Case Report and Review of Literature

Giant cell tumor (GCT) of the proximal femur poses various challenges in its management and recurrence. We present a rare case of GCT of proximal femur in which recurrence and coxa vara deformity were encountered after index surgery. Management of the recurrence was done with intramedullary fixation with extended curettage and bone grafting. Different aspects of management such as the role of defect size, adjuvants, bone cement/bone graft, implants, and bisphosphonates have been highlighted in this article.

Outcomes of Osteoid Osteoma Treated by Percutaneous CT-Guided Radiofrequency Ablation

Introduction Osteoid osteomas are the most frequent true benign bone tumor in the adolescent age group and the third most prevalent benign bone tumor overall. This study was designed to assess the effectiveness of the procedure and correlate it with the analgesia offered because of the significant burden of this illness and new literature supporting the successful outcomes of image-guided percutaneous radiofrequency ablation (RFA) in osteoid osteoma. Methodology  This hospital-based interventional trial was carried out in a tertiary care referral center. Forty-two patients with osteoid osteoma, ranging in age from 9 to 30, were included in the study. The patients received RFA guided by computed tomography (CT), and they were postoperatively monitored at one, two, and four weeks and three, six months, and 12 months. A numerical pain scale (NPS) was used to evaluate the patient's pain both before and after the procedure. The preoperative and postoperative results were contrasted. Results A total of 42 participants were enrolled in the study. Eight (19.05%) women and 34 (80.95%) men made up the group. Complete pain alleviation (NPS=0) was attained in 42.8% and 96.4% of the study group in the first and second weeks post-procedure. Almost all patients began protected weight-bearing at one week, according to their level of pain tolerance. Osteoid osteoma of the talus was a remnant lesion in one patient that required further treatment after two weeks. During the duration of the follow-up, no problems were recorded. Conclusion Percutaneous CT-guided RFA of osteoid osteoma is a safe, minimally invasive procedure and greatly reduces the duration of hospitalization. It has excellent functional outcomes and no known complications.

A Computed Tomography-Based Radiomics Analysis of Low-Energy Proximal Femur Fractures in the Elderly Patients

INTRODUCTION

Low-energy proximal femur fractures in elderly patients result from factors, like osteoporosis and falls. These fractures impose high rates of economic and social costs. In this study, we aimed to build predictive models by applying machine learning (ML) methods on radiomics features to predict low-energy proximal femur fractures.

METHODS

Computed tomography scans of 40 patients (mean ± standard deviation of age = 71 ± 6) with low-energy proximal femur fractures (before a fracture occurs) and 40 individuals (mean ± standard deviation of age = 73 ± 7) as a control group were included. The regions of interest, including neck, trochanteric, and intertrochanteric, were drawn manually. The combinations of 25 classification methods and 8 feature selection methods were applied to radiomics features extracted from ROIs. Accuracy and the area under the receiver operator characteristic curve (AUC) were used to assess ML models' performance.

RESULTS

AUC and accuracy values ranged from 0.408 to 1 and 0.697 to 1, respectively. Three classification methods, including multilayer perceptron (MLP), sequential minimal optimization (SMO), and stochastic gradient descent (SGD), in combination with the feature selection method, SVM attribute evaluation (SAE), exhibited the highest performance in the neck (AUC= 0.999, 0.971 and 0.971, respectively; accuracy = 0.988, 0.988, and 0.988, respectively) and the trochanteric (AUC = 1, 1 and 1, respectively; accuracy = 1, 1 and 1, respectively) regions. The same methods demonstrated the highest performance for the combination of the 3 ROIs' features (AUC = 1, 1 and 1, respectively; accuracy =1, 1 and 1, respectively). In the intertrochanteric region, the combination methods, MLP+SAE, SMO+SAE, and SGD+SAE, as well as the combination of the SAE method and logistic regression (LR) classification method exhibited the highest performance (AUC= 1, 1, 1 and 1, respectively; accuracy= 1, 1, 1 and 1, respectively).

CONCLUSION

Applying machine learning methods to radiomics features is a powerful tool to predict low-energy proximal femur fractures. The results of this study can be verified by conducting more research on bigger datasets.

Temporary bridging trans-hip external fixation in damage control orthopaedics treatment after severe combat trauma: A clinical case series

The role of external fixation in Damage Control Orthopaedics has been well described. Temporary external fixation has been recommended to provide relative bone stability while the soft tissue heals, prior to formal open reduction and internal fixation. Temporary bridging external fixation, that spans the joint, is recommended as primary skeletal stabilization in complex intra-articular and peri-articular fractures, in extensive peri-articular soft-tissue damage around the knee, ankle, elbow and wrist joints. Works devoted to temporary trans-hip external fixation in treatment of complex high-energy injuries are relatively rare. The purpose of this article is to present our experience in using temporary hip spanning external fixation during primary treatment of six patients suffered from complex open intra-articular and peri-articular fractures of the proximal femoral bone with extensive soft tissue damage due to war blast or high-velocity gunshot trauma. Primary management was based on the concept of Advanced Trauma Life Support and Damage Control Orthopaedics. Conversion to definitive bone reconstruction was performed on the next stage of the treatment after general and local stabilization.

Application of statistical shape modeling to the human hip joint: a scoping review

OBJECTIVE

The objective of this scoping review was to identify all examples of the application of statistical shape models to the human hip joint, with a focus on applications, population, methodology, and validation.

INTRODUCTION

Clinical radiographs are the most common imaging tool for management of hip conditions, but it is unclear whether radiographs can adequately diagnose or predict outcomes of 3D deformity. Statistical shape modeling, a method of describing the variation of a population of shapes using a small number of variables, has been identified as a useful tool to associate 2D images with 3D anatomy. This could allow clinicians and researchers to validate clinical radiographic measures of hip deformity, develop new ones, or predict 3D morphology directly from radiographs. In identifying all previous examples of statistical shape modeling applied to the human hip joint, this review determined the prevalence, strengths, and weaknesses, and identified gaps in the literature.

INCLUSION CRITERIA

Participants included any human population. The concept included development or application of statistical shape models based on discrete landmarks and principal component analysis. The context included sources that exclusively modeled the hip joint. Only peer-reviewed original research journal articles were eligible for inclusion.

METHODS

We searched MEDLINE, Embase, Cochrane CENTRAL, IEEE Xplore, Web of Science Core Collection, OCLC PapersFirst, OCLC Proceedings, Networked Digital Library of Theses and Dissertations, ProQuest Dissertations and Theses Global, and Google Scholar for sources published in English between 1992 and 2021. Two reviewers screened sources against the inclusion criteria independently and in duplicate. Data were extracted by 2 reviewers using a REDCap form designed to answer the review study questions, and are presented in narrative, tabular, and graphical form.

RESULTS

A total of 104 sources were considered eligible based on the inclusion criteria. From these, 122 unique statistical shape models of the human hip were identified based on 86 unique training populations. Models were most often applied as one-off research tools to describe shape in certain populations or to predict outcomes. The demographics of training populations were skewed toward older patients in high-income countries. A mean age between 60 and 79 years was reported in 29 training populations (34%), more than reported in all other age groups combined, and 73 training populations (85%) were reported or inferred to be from Europe and the Americas. Only 4 studies created models in a pediatric population, although 15 articles considered shape variation over time in some way. There were approximately equal numbers of 2D and 3D models. A variety of methods for labeling the training set was observed. Most articles presented some form of validation such as reporting a model's compactness (n = 71), but in-depth validation was rare.

CONCLUSIONS

Despite the high volume of literature concerning statistical shape models of the human hip, there remains a need for further research in key areas. We identified the lack of models in pediatric populations and low- and middle-income countries as a notable limitation to be addressed in future research.

An Uncommon Case Report: Pathologic Fracture in a Proximal Femur Aneurysmal Bone Cyst in a Child

Introduction

Aneurysmal bone cysts (ABCs) are a group of benign, expansile, locally aggressive lesion characterized by fluid-filled cysts usually in the metaphyseal end of long bones. They usually affect children and young adults, with an atypical etiology and uncommon presentation. Treatment modalities include en bloc resection and curettage with or without bone graft or bone substitute augmentation with instrumentation, sclerosing agents, arterial embolization, and adjuvant radiotherapy.

Case Report

We report a rare case of ABC with pathological fracture in the proximal femur of a 13-year-old male patient, who presented to the emergency department with severe pain in the right hip and inability to walk following trivial fall while playing. Curettage with open biopsy was performed followed by implantation with modified hydroxyapatite granules and internal fixation for the subtrochanteric fracture with pediatric dynamic hip screw and four hole plate, with a favorable outcome.

Conclusion

There is a lack of a standard guideline for the management on account of uniqueness of these cases; curettage with bone graft or bone substitutes in conjunction with internal fixation of associated pathologic fracture yields bony union with adequate clinical results.

Quantitative Load Dependency Analysis of Local Trabecular Bone Microstructure to Understand the Spatial Characteristics in the Synthetic Proximal Femur

Analysis of the dependency of the trabecular structure on loading conditions is essential for understanding and predicting bone structure formation. Although previous studies have investigated the relationship between loads and structural adaptations, there is a need for an in-depth analysis of this relationship based on the bone region and load specifics. In this study, the load dependency of the trabecular bone microstructure for twelve regions of interest (ROIs) in the synthetic proximal femur was quantitatively analyzed to understand the spatial characteristics under seven different loading conditions. To investigate the load dependency, a quantitative measure, called the load dependency score (LDS), was established based on the statistics of the strain energy density (SED) distribution. The results showed that for the global model and epiphysis ROIs, bone microstructures relied on the multiple-loading condition, whereas the structures in the metaphysis depended on single or double loads. These results demonstrate that a given ROI is predominantly dependent on a particular loading condition. The results confirm that the dependency analysis of the load effects for ROIs should be performed both qualitatively and quantitatively.

Prediction of osteoporosis from proximal femoral cortical bone thickness and Hounsfield unit value with clinical significance

Background

Utilizing dual-energy x-ray absorptiometry (DXA) to assess bone mineral density (BMD) was not routine in many clinical scenarios, leading to missed diagnoses of osteoporosis. The objective of this study is to obtain effective parameters from hip computer tomography (CT) to screen patients with osteoporosis and predict their clinical outcomes.

Methods

A total of 375 patients with hip CT scans for intertrochanteric fracture were included. Among them, 56 patients possessed the data of both hip CT scans and DXA and were settled as a training group. The cortical bone thickness (CTh) and Hounsfield unit (HU) values were abstracted from 31 regions of interest (ROIs) of the proximal femur. In the training group, the correlations between these parameters and BMD were investigated, and their diagnostic efficiency of osteoporosis was assessed. Finally, 375 patients were divided into osteoporotic and nonosteoporotic groups based on the optimal cut-off values, and the clinical difference between subgroups was evaluated.

Results

The CTh value of ROI 21 and the HU value of ROI 14 were moderately correlated with the hip BMD [r = 0.475 and 0.445 (p < 0.001), respectively]. The best diagnostic effect could be obtained by defining osteoporosis as CTh value < 3.19 mm in ROI 21 or HU value < 424.97 HU in ROI 14, with accuracies of 0.821 and 0.883, sensitivities of 84% and 76%, and specificities of 71% and 87%, respectively. The clinical outcome of the nonosteoporotic group was better than that of the osteoporotic group regardless of the division criteria.

Conclusion

The CTh and HU values of specific cortex sites in the proximal femur were positively correlated with BMD of DXA at the hip. Thresholds for osteoporosis based on CTh and HU values could be utilized to screen osteoporosis and predict clinical outcomes.

Prediction of femoral strength of elderly men based on quantitative computed tomography images using machine learning

Hip fracture is the most common complication of osteoporosis, and its major contributor is compromised femoral strength. This study aimed to develop practical machine learning models based on clinical quantitative computed tomography (QCT) images for predicting proximal femoral strength. Eighty subjects with entire QCT data of the right hip region were randomly selected from the full MrOS cohorts, and their proximal femoral strengths were calculated by QCT-based finite element analysis (QCT/FEA). A total of 50 parameters of each femur were extracted from QCT images as the candidate predictors of femoral strength, including grayscale distribution, regional cortical bone mapping (CBM) measurements, and geometric parameters. These parameters were simplified by using feature selection and dimensionality reduction. Support vector regression (SVR) was used as the machine learning algorithm to develop the prediction models, and the performance of each SVR model was quantified by the mean squared error (MSE), the coefficient of determination (R² ), the mean bias, and the SD of bias. For feature selection, the best prediction performance of SVR models was achieved by integrating the grayscale value of 30% percentile and specific regional CBM measurements (MSE ≤ 0.016, R² ≥ 0.93); and for dimensionality reduction, the best prediction performance of SVR models was achieved by extracting principal components with eigenvalues greater than 1.0 (MSE ≤ 0.014, R² ≥ 0.93). The femoral strengths predicted from the well-trained SVR models were in good agreement with those derived from QCT/FEA. This study provided effective machine learning models for femoral strength prediction, and they may have great potential in clinical bone health assessments.

Impact of COVID-19 Pandemic on Treatment and Outcome of Fragility Hip Fractures In Non-COVID Patients: Comparison Between the Lockdown Period, a Historical Series and the "Pandemic Normality" in a Single Institution

Introduction

The COVID-19 pandemic has affected and is still deeply affecting all aspects of public life. World governments have been forced to enact restrictive measures to stem the contagion which have led to a decrease in the movement of people within national territory and to a redirection of health care resources with a suspension of non-urgent procedures. In Italy, a lockdown was imposed from March 9^th to May 3^rd, 2020. As a result, a significant reduction in the overall operative volume of orthopedic trauma was expected, but it was not possible to predict a similar trend regarding fragility fractures of the proximal femur in the elderly.

Methods

The aim of this paper was to examine the impact of COVID-19 on the operating volume for trauma surgeries and to determine how the pandemic affected the management of fragility hip fractures (FHFs) in non-COVID patients at a single Institution.

Results

The first result was a statistically significant reduction in the overall operative volume of orthopedic trauma during the period of the first lockdown and an increase in the mean age of patients undergoing surgery, as expected. As regard to the second aim, the incidence of FHFs remained almost unchanged during the periods analysed. The population examined were superimposable in terms of demographics, comorbidities, type of fracture, peri-operative complications, percentage of operations performed within 48 hours from hospitalization and 1-year outcome.

Discussion

Our results are in line with those already present in the Literature.

Conclusions

Our study revealed a significant impact of the restrictive anti-contagion measures on the overall orthopedic surgical volume, but, at the same time, we could affirm that the pandemic did not affect the management of FHFs in non-COVID patients, and their results.

Completely Displaced Femoral Neck Stress Fracture in a Young Male Soldier With Almost No Functional Impact: A Case Report

Stress fracture in general is a well-known condition that can be found commonly in healthy athletes and military personnel. These fractures occur due to bone fatigue in response to the repetitive stress of exercise. Although few reports on stress fractures among military personnel and active young athletes can be found in previous literature, we present this case report of a young military soldier that had a completely displaced neck of femur fracture with no functional limitation for seven days prior to seeking medical advice; the patient was operated on and followed for three years after and did not develop complications associated with this kind of fracture. A reduction of neck of femur fracture and fixation in valgus position to maintain good reduction with weight-bearing as done in our case have assisted in reducing avascular necrosis (AVN) risk despite the high displacement and delayed operative intervention due to the patient's late presentation.

Risk factors for fracture in patients with fibrous dysplasia of the proximal femur

OBJECTIVE

The primary aim of this retrospective observational clinical study was to explore the risk factors for fracture in patients with fibrous dysplasia (FD) of the proximal femur.

METHODS

We investigated body mass index, bilateral radiographs on both sides, femoral neck shaft angle measurements, and markers of bone metabolism in patients with FD of the proximal femur according to whether or not they had sustained a hip fracture. Nine clinical parameters (age, sex, clinical classification, anatomic classification, femoral neck shaft angle, and procollagen type 1 N-terminal propeptide, C-terminal telopeptide of type I collagen, and osteocalcin levels) were selected for univariate analysis. Factors that were significant in univariate analysis were then subjected to multivariate logistic analysis.

RESULTS

Clinical classification, anatomic classification, femoral neck shaft angle, and the osteocalcin level were identified to be statistically significant risk factors for fracture in univariate analysis. Anatomic classification, femoral neck shaft angle, and the osteocalcin level remained significant risk factors in multivariate analysis.

CONCLUSIONS

Anatomic classification, femoral neck shaft angle, and the osteocalcin level are important risk factors for fracture in patients with FD of the proximal femur and could be used to guide implementation of a fracture prevention strategy in these patients.

Low-grade myofibroblastic sarcoma of the proximal femur: A case report and literature review

RATIONAL

Low-grade myofibroblastic sarcoma (LGMS) is an atypical type of tumor composed of myofibroblasts. LGMS in the femoral head neck junction is extremely rare and no case treated by hip arthroscopy was reported.

PATIENT CONCERNS

We reported a case of LGMS in the femoral head neck junction treated by hip arthroscopy. A 30-year-old female was admitted to our hospital with discomfort and pain after left hip sprained one year prior. Physical examination revealed swelling of the left hip and magnetic resonance images showed a soft tissue mass in the femoral head neck junction.

DIAGNOSIS

Via microscopy of pathological specimens, spindle cell proliferative lesions, atypia of some cells, and mitotic figures/pathological mitotic figures of some cells were observed. Immunohistochemistry revealed positive for smooth muscle actin, focally positive for CD34 and CD68, while negative for S-100, desmin, and anaplastic lymphoma kinase. The imaging, histomorphological and immunohistochemical features suggested a final diagnosis of LGMS of the proximal femur.

INTERVENTIONS

This patient underwent hip arthroscopy for excision of the soft tissue mass.

OUTCOMES

The clinical and imaging follow-up at 6 months postoperatively showed that surgery had achieved good clinical outcomes.

LESSONS

To the best of our knowledge, this is the first case report of LGMS in the femoral head neck junction treated by hip arthroscopy. Beyond the present case, other 120 cases from 58 literatures (1998-2022) are reviewed and discussed. The age of LGMS patients ranged from 11 months to 77 years and the male-to-female ratio was approximately 1.28:1. The location distribution of previously reported LGMS cases and the present case was as follows: Head&neck (45.90%), trunk (30.33%), and extremity (23.77%). Hip arthroscopic excision of LGMS may achieve relatively good clinical outcomes.

Topology Optimization-Based Localized Bone Microstructure Reconstruction for Image Resolution Enhancement: Accuracy and Efficiency

Topology optimization is currently the only way to provide bone microstructure information by enhancing a 600 μm low-resolution image into a 50 μm high-resolution image. Particularly, the recently proposed localized reconstruction method for the region of interest has received much attention because it has a high possibility to overcome inefficiency such as iterative large-scale problems of the conventional reconstruction. Despite the great potential, the localized method should be thoroughly validated for clinical application. This study aims to quantitatively validate the topology optimization-based localized bone microstructure reconstruction method in terms of accuracy and efficiency by comparing the conventional method. For this purpose, this study re-constructed bone microstructure for three regions of interest in the proximal femur by localized and conventional methods, respectively. In the comparison, the dramatically reduced total progress time by at least 88.2% (20.1 h) as well as computational resources by more than 95.9% (54.0 gigabytes) were found. Moreover, very high reconstruction accuracy in the trabecular alignment (up to 99.6%) and morphometric indices (up to 2.71%) was also found. These results indicated that the localized method could reconstruct bone microstructure, much more effectively preserving the originality of the conventional method.

Triangular Mechanical Structure of the Proximal Femur

Objective

The mechanical high modulus structure of the proximal femur could guide clinical surgical treatment and instrument design of proximal femoral fractures. The purpose of this study is to analyze and verify the mechanical structure of the proximal femur.

Methods

A total of 375 patients with intertrochanteric fractures were imaged using computed tomography (CT) scans. Patients were grouped according to age and sex. Cortical and medullary cavity parameters (cortical thickness [CTh], cortical mean density [CM], upper‐lower diameter length [ULL], and medial‐lateral diameter length [MLL]) were measured at eight planes. Six proximal femoral finite element models of different sexes and ages were constructed. To verify the measurement results, Abaqus was used to implement the force load to describe the von Mises stress distribution, and the maximum von Mises stress values of each wall of the proximal femur were compared.

Results

The CTh values of the lower and upper walls were higher than those of the anterior and posterior walls of the femoral neck (p < 0.05). The CM values of the lower and upper walls were higher than those of the anterior and posterior walls of the subcephalic and middle femoral neck (p < 0.05). The ULL value gradually increased from the subcephalic region to the bottom (p < 0.05). The CTh and CM values of the medial and lateral walls were higher than those of the anterior and posterior walls in the femoral trochanteric region (p < 0.05). The MLL value decreased gradually from the plane 20 mm above the upper edge to that 20 mm below the vertex of the femoral lesser trochanter (p < 0.05). The von Mises stress was concentrated on the upper and lower walls of the femoral neck and on the medial and lateral walls of the femoral trochanteric region. The maximum von Mises stress values of the upper and lower walls were higher than those of the anterior and posterior walls of the femoral neck. The maximum von Mises stress values of the medial and lateral walls were higher than those of the anterior and posterior walls in the femoral trochanteric region, except for the plane 20 mm above the upper edge of the femoral lesser trochanter.

Conclusion

The bone mass of the proximal femur presented a triangular high‐modulus distribution, which bore the main stress of the proximal femur. The triangular mechanical structure provides a guideline for the surgical strategy and instrument design of the proximal femur.

Proximal femur fractures in patients taking anti-coagulants: has anything changed?

With an ever-ageing population, the incidence of hip fractures is increasing worldwide. Increasing age is not just associated with increasing fractures but also increasing comorbidities and polypharmacy.

Consequently, a large proportion of patients requiring hip fracture surgery (HFS) are also prescribed antiplatelet and anti-coagulant medication. There remains a clinical conundrum with regards to how such medications should affect surgery, namely with regards to anaesthetic options, timing of surgery, stopping and starting the medication as well as the need for reversal agents.

Herein, we present the up-to-date evidence on HFS management in patients taking blood-thinning agents and provide a summary of recommendations based on the existing literature.

Aneurysmal bone cyst of the proximal femur concomitant with Graves' disease and Moyamoya disease: report of a rare case

Aneurysmal bone cyst is a type of benign bone pathology with expansile and osteolytic features whose etiology remains unclear. Graves' disease is an autoimmune disease characterized by diffuse goiter and hyperthyroidism. Moyamoya disease is a progressive cerebral vasculopathy. It has been reported that Graves' disease and Moyamoya disease share a similar etiology involving cytokines and autoimmune and genetic factors. There are no previous reports regarding the relationship between aneurysmal bone cyst and Graves' disease. Here, we present the rare case of a 25-year-old woman with suspected aneurysmal bone cyst of the left proximal femur and a definite preoperative diagnosis of Graves' disease, in whom lesion resection combined with left total hip replacement was indicated. Biopsy confirmed the diagnosis of aneurysmal bone cyst. Three days postoperatively, the patient developed acute ischemic cerebral infarction owing to Moyamoya disease, which was subsequently confirmed. This case elucidates the potential interaction among aneurysmal bone cysts, Graves' disease, and Moyamoya disease and provides lessons regarding appropriate perioperative preparation for patients with Graves' disease who require surgery to avoid potential severe complications.

Sensitivity of the stress field of the proximal femur predicted by CT-based FE analysis to modeling uncertainties

Proximal femur anatomy and bone mineral density vary widely among individuals, precluding the use of one predefined finite element (FE) model to determine the stress field for all proximal femurs. This variability poses a challenge in current prosthetic hip design approach. Given the numerous options for generating computed tomography (CT)-based FE models, selecting the best methods for defining the mechanical behavior of the proximal femur is difficult. In this study, a combination of computational and experimental approaches was used to explore the susceptibility of the predicted stress field of the proximal femur to different combinations of density-elasticity relationships, element type, element size, and calibration error. Our results suggest that FE models with first-order voxelized elements generated by the Keyak and Falkinstein density-elasticity relationship or quadratic tetrahedral elements generated by the Morgan density-elasticity relationship lead to accurate estimations of the mechanical behavior of human femurs. Other combinations of element size, element type, and mathematical relationships produce less accurate results, especially in the cortical bone of the femoral neck and calcar region. The voxelized model was more susceptible to variation of element size and density-elasticity relationships than FE models with quadratic tetrahedral elements. Regardless of element type, the stress fields predicted by the Keyak and Falkinstein and the Morgan relationships were the most robust to calibration error when deriving material density from CT-generated Hounsfield data. These results provide insight into the implementation of a robust platform for designing patient-specific implants capable of maintaining or modifying the stress in bones.

Prophylactic surgical treatment using CT-based rigidity analysis vs. after the fact fracture treatment of pathologic femoral lesions

Background

Accurate comparison of prophylactic surgical treatment (PST) to after fracture treatment (AF) of patients with femoral metastatic disease requires more accurately identifying patients for impending fracture, such as with CT-based structural rigidity analysis (CTRA). This study compares a more accurately defined PST group (of impending fractures defined by CTRA) to AF for metastatic femoral disease.

Methods

PST patients were enrolled and treated by the PI in a longitudinal multicenter study of impending pathologic fractures evaluated for accuracy by CTRA. The AF patients were also treated by the senior author and were identified by retrospective chart review. Fifty-five patients were treated surgically for metastatic femoral lesions and were divided into three groups for the purpose of this study: Group I (AF), Group II (PST-high), and Group III (PST-low). Demographic information, comorbidities, and clinical variables of interest were collected by retrospective chart review; cost data was collected by collaboration with our hospital financial personnel (office of the Chief Financial Officer).

Results

Survival showed statistically significant differences favoring Group II. Transfusions in Group I were nearly twice those of Groups II and III, but there was no statistically significant (NS) difference between groups. Estimated blood loss (EBL) was generally with NS difference. Similarly, there were NS differences in LOS between groups. Discharge disposition showed statistically significant differences between groups (P=0.012, global). Discharge to home was highest in Group II (76%) and lowest in Group I (27%). Discharge to rehab was lowest in Group II (24%) and highest in Group I (47%). There were no discharges to hospice or morgue in Group II, while both occurred in Group I. Mean direct and total costs were highest in Group I ($18,837 and $31,997, respectively) and lowest in Group II ($16,094 and $27,357) but the differences were NS.

Conclusions

This study shows benefits of PST over AF in a group of PST patients more accurately defined to have impending pathologic fractures by CTRA definition.

Implant survival and functional results of endoprosthetic reconstruction for proximal femoral metastases with pathological fractures

BACKGROUND

This study aimed to evaluate the patient and implant survival, clinical and functional outcomes, and the rate of complications resulting in reconstruction failure following endoprosthetic reconstruction (EPR) of extensive proximal femoral metastases associated with actual or impending pathological fractures.

METHODS

A total of 111 patients with actual or impending pathological fractures due to metastatic disease of the proximal femur were treated with EPR between 2003 and 2018. Staged surgery, bilateral EPR, was performed in 3 cases. The patients comprised 51 females and 60 males with a mean age of 52.1 ± 12.3 years. The patient and implant survival were recorded. Clinical and functional outcomes were assessed by using the visual analogue scale (VAS), Musculoskeletal Tumour Society (MSTS) functional scoring, and Karnofsky Performance Scale (KPS). The different types of abductor mechanism repair were evaluated by functional tests and existence of Trendelenburg gait at postoperative follow-ups. The complications resulting in reconstruction failure were investigated.

RESULTS

The mean follow-up was 23.1 ± 17.9 months. The overall survival of patients after EPR was 89% at 6 months, 72% at 1 year and 10% at 5 years. The estimated 1- and 5-year overall implant survival was 100% and 97.3% (95% CI, 0.95-0.98), respectively, as the endpoint was defined as complete removal of the prosthesis. Median VAS score before endoprosthetic replacement was 8 and after 3 months 4. Before surgery, the median MSTS score was 40 (30-56.6%) and the median KPS score was 40 (30-50). Postoperative third month, the median MSTS score was 56.6 (53.3-86.6%) and the median KPS score was 60 (40-70). Functional scores were superior in trochanter major split osteotomized group compared to trochanter major removed group. Trendelenburg gait was seen in 20 (17.5%) patients postoperatively. There were 10 (8.7%) complications resulting in reconstruction failure.

CONCLUSION

Endoprosthetic replacement can provide a durable fixation with high implant survival rate and good clinical and functional results in extensive proximal femoral metastases associated with a pathological fracture.

The accuracy of restoration of femoral head centre of rotation in the anteroposterior plane after uncemented total hip arthroplasty : a CT-based study

AIMS

Hip arthroplasty aims to accurately recreate joint biomechanics. Considerable attention has been paid to vertical and horizontal offset, but femoral head centre in the anteroposterior (AP) plane has received little attention. This study investigates the accuracy of restoration of joint centre of rotation in the AP plane.

METHODS

Postoperative CT scans of 40 patients who underwent unilateral uncemented total hip arthroplasty were analyzed. Anteroposterior offset (APO) and femoral anteversion were measured on both the operated and non-operated sides. Sagittal tilt of the femoral stem was also measured. APO measured on axial slices was defined as the perpendicular distance between a line drawn from the anterior most point of the proximal femur (anterior reference line) to the centre of the femoral head. The anterior reference line was made parallel to the posterior condylar axis of the knee to correct for rotation.

RESULTS

Overall, 26/40 hips had a centre of rotation displaced posteriorly compared to the contralateral hip, increasing to 33/40 once corrected for sagittal tilt, with a mean posterior displacement of 7 mm. Linear regression analysis indicated that stem anteversion needed to be increased by 10.8° to recreate the head centre in the AP plane. Merely matching the native version would result in a 12 mm posterior displacement.

CONCLUSION

This study demonstrates the significant incidence of posterior displacement of the head centre in uncemented hip arthroplasty. Effects of such displacement include a reduction in impingement free range of motion, potential alterations in muscle force vectors and lever arms, and impaired proprioception due to muscle fibre reorientation. Cite this article: Bone Joint Res 2022;11(3):180-188.

Bone Ingrowth Around an Uncemented Femoral Implant Using Mechanoregulatory Algorithm: A Multiscale Finite Element Analysis

The primary fixation and long-term stability of a cementless femoral implant depend on bone ingrowth within the porous coating. Although attempts were made to quantify the peri-implant bone ingrowth using the finite element (FE) analysis and mechanoregulatory principles, the tissue differentiation patterns on a porous-coated hip stem have scarcely been investigated. The objective of this study is to predict the spatial distribution of evolutionary bone ingrowth around an uncemented hip stem, using a three-dimensional (3D) multiscale mechanobiology-based numerical framework. Multiple load cases representing a variety of daily living activities, including walking, stair climbing, sitting down, and standing up from a chair, were used as applied loading conditions. The study accounted for the local variations in host bone material properties and implant-bone relative displacements of the macroscale implanted FE model, in order to predict bone ingrowth in microscale representative volume elements (RVEs) of 12 interfacial regions. In majority RVEs, 20-70% bone tissue (immature and mature) was predicted after 2 months, contributing toward a progressive increase in average Young's modulus (1200-3000 MPa) of the interbead tissue layer. Higher bone ingrowth (mostly greater than 60%) was predicted in the anterolateral regions of the implant, as compared to the posteromedial side (20-50%). New bone tissue was formed deeper inside the interbead spacing, adhering to the implant surface. The study helps to gain an insight into the degree of osseointegration of a porous-coated femoral implant.

Associations of muscle size and fatty infiltration with bone mineral density of the proximal femur bone

PURPOSE

To investigate the relationship of muscle atrophy and fat infiltration around the hip joint with areal bone mineral density (aBMD) in each subregion of the proximal femur.

MATERIALS AND METHODS

In total, 144 participants (66 women and 78 men) were examined by quantitative computed tomography (QCT), and areal bone mineral density (aBMD) of the femoral neck (FN), trochanter (TR), and intertrochanter (IT) of the proximal femur were obtained. The cross-sectional area (CSA) and proton density fat fraction (PDFF) of the gluteus maximus (G.MaxM), gluteus medius (G.MedM), gluteus minimus (G.MinM), and iliopsoas (IliopM) were obtained via magnetic resonance imaging (MRI) using the mDIXON-Quant sequence. A multivariate generalized linear model was used to evaluate the correlation of the CSA and PDFF of muscles with aBMD in all subregions of the proximal femur.

RESULTS

The FN integral (Int) aBMD was significantly associated with the G.MaxM CSA (men: P = 0.002; women: P = 0.008) and PDFF (men: P < 0.001; women: P = 0.047). Some muscle indexes were related to the FN aBMD in males or females, including the CSA of G.MedM, G.MinM, and IliopM as well as the PDFF of IliopM and G.MinM. Associations of hip muscle parameters with the TR Int aBMD in both males and females were observed, including G.MaxM CSA (men: P < 0.001; women: P = 0.028) and G.MaxM PDFF (men: P = 0.031; women: P = 0.038). Other muscle indexes, including G.MedM and IliopM, were related to the TR aBMD, mainly affecting the aBMD of TR cortical (Cort) and TR Int. The IT Int aBMD and IT Cort aBMD showed significant correlation with the muscle indexes of G. MaxM, IliopM, and G.MedM, including the PDFF and CSA in males and females. Further, more indicators of the G.MedM and IliopM correlated with the TR and IT aBMD compared to the FN aBMD.

CONCLUSIONS

The CSA of gluteus muscles and iliopsoas had a positive association with the aBMD in the proximal femur, and the PDFF of gluteus muscles and iliopsoas had a negative correlation with the aBMD in the proximal femur. In addition, there was an interaction of the proximal femur aBMD with the muscle size and fatty infiltration of hip muscles.

Prevalence of Enchondromas of the Proximal Femur in Adults as an Incidental Finding on MRI of the Pelvis

Objective  To determine the prevalence of enchondroma in adults as an incidental finding in the proximal femur on magnetic resonance imaging (MRI). Materials and Methods  A retrospective review of the MRI scans of the pelvis in a series of adult patients was conducted. All presented with nononcological musculoskeletal complaints. The site, size, and appearances of the enchondromas were identified according to criteria from previous studies. Results  A total of 1,209 proximal femora in 610 patients were reviewed and a total of 9 enchondromas were identified. These ranged from 0.6 to 2.5 cm in length (mean 1.3 cm). None showed aggressive features suggestive of malignancy. Three cases (33%) underwent follow-up MRI scans which showed no change in size or morphology. Conclusion  The prevalence on MRI of incidental enchondromas arising in the proximal femur is 0.7%. This is three to four times less common than seen in the proximal humerus and around the knee.

Intertrochanteric valgus osteotomy for post-traumatic coxa vara after proximal femur fractures: A retrospective study

To investigate the clinical effects of a new intertrochanteric valgus osteotomy technique designed by the authors for treatment of post-traumatic coxa varus after proximal femur fractures. Retrospectively analyzed 11 patients who developed coxa vara after sustaining proximal femoral fractures were treated with intertrochanteric valgus osteotomy from December 2005 to December 2018 in our hospital. This study included 6 cases of intertrochanteric fracture deformity union, 3 cases of subtrochanteric fracture nonunion and 2 cases of femoral neck fracture nonunion. Measured the degree of coxa varus, the differences in the lower limb length and force line in all patients. Evaluated hip function with the Harris hip score. All injuries were treated with the authors' intertrochanteric valgus osteotomy technique. The average follow-up period was 3 years and evaluated the clinical effects by radiological examination and the Harris hip score. The average neck-shaft angle increased 35.0° (99.1°-134.1°) and the average limb shortening lengthened 1.9 cm (2.9-1.0 cm) after surgery. The average operating time was 67.2 minutes and blood loss was 237.7 ml. The osteotomy position healed in all patients 3 months later. Union of the 2 old femoral neck fractures was achieved 4 and 6 months after surgery, respectively, and no femoral head necrosis occurred during follow-up. The Harris hip score increased an average of 49 points (44.1-93.1 points) at 1 year postoperatively. Our self-designed intertrochanteric valgus osteotomy technique showed a favorable clinical effect to treatment coxa vara and can be used in the clinical setting.

Leg length discrepancy in patients with Perthes' disease : a note of caution for the arthroplasty surgeon

AIMS

Perthes' disease (PD) often results in femoral head deformity and leg length discrepancy (LLD). Our objective was to analyze femoral morphology in PD patients at skeletal maturity to assess where the LLD originates, and evaluate the effect of contralateral epiphysiodesis for length equalization on proximal and subtrochanteric femoral lengths.

METHODS

All patients treated for PD in our institution between January 2013 and June 2020 were reviewed retrospectively. Patients with unilateral PD, LLD of ≥ 5 mm, and long-leg standing radiographs at skeletal maturity were included. Total leg length, femoral and tibial length, articulotrochanteric distance (ATD), and subtrochanteric femoral length were compared between PD side and the unaffected side. Furthermore, we compared leg length measurements between patients who did and who did not have a contralateral epiphysiodesis.

RESULTS

Overall, 79 patients were included, of whom 21 underwent contralateral epiphysiodesis for leg length correction. In the complete cohort, the mean LLD was 1.8 cm (95% confidence interval (CI) 1.5 to 2.0), mean ATD difference was 1.8 cm (95% CI -2.1 to -1.9), and mean subtrochanteric difference was -0.2 cm (95% CI -0.4 to 0.1). In the epiphysiodesis group, the mean LLD before epiphysiodesis was 2.7 cm (95% CI 1.3 to 3.4) and 1.3 cm (95% CI -0.5 to 3.8) at skeletal maturity. In the nonepiphysiodesis group the mean LLD was 2.0 cm (95% CI 0.5 to 5.1; p = 0.016). The subtrochanteric region on the PD side was significantly longer at skeletal maturity in the epiphysiodesis group compared to the nonepiphysiodesis group (-1.0 cm (95% CI -2.4 to 0.6) vs 0.1 cm (95% CI -1.0 to 2.1); p < 0.001).

CONCLUSION

This study demonstrates that LLD after PD originates from the proximal segment only. In patients who had contralateral epiphysiodesis to balance leg length, this is achieved by creating a difference in subtrochanteric length. Arthroplasty surgeons need to be aware that shortening of the proximal femur segment in PD patients may be misleading, as the ipsilateral subtrochanteric length in these patients can be longer. Therefore, we strongly advise long-leg standing films for THA planning in PD patients in order to avoid inadvertently lengthening the limb. Cite this article: Bone Joint J 2021;103-B(11):1736-1741.

Resection of the proximal femur during one-stage revision for infected hip arthroplasty : risk factors and effectiveness

AIMS

One-stage revision hip arthroplasty for periprosthetic joint infection (PJI) has several advantages; however, resection of the proximal femur might be necessary to achieve higher success rates. We investigated the risk factors for resection and re-revisions, and assessed complications and subsequent re-revisions.

METHODS

In this single-centre, case-control study, 57 patients who underwent one-stage revision arthroplasty for PJI of the hip and required resection of the proximal femur between 2009 and 2018 were identified. The control group consisted of 57 patients undergoing one-stage revision without bony resection. Logistic regression analysis was performed to identify any correlation with resection and the risk factors for re-revisions. Rates of all-causes re-revision, reinfection, and instability were compared between groups.

RESULTS

Patients who required resection of the proximal femur were found to have a higher all-cause re-revision rate (29.8% vs 10.5%; p = 0.018), largely due to reinfection (15.8% vs 0%; p = 0.003), and dislocation (8.8% vs 10.5%; p = 0.762), and showed higher rate of in-hospital wound haematoma requiring aspiration or evacuation (p = 0.013), and wound revision (p = 0.008). The use of of dual mobility components/constrained liner in the resection group was higher than that of controls (94.7% vs 36.8%; p < 0.001). The presence and removal of additional metal hardware (odds ratio (OR) = 7.2), a sinus tract (OR 4), ten years' time interval between primary implantation and index infection (OR 3.3), and previous hip revision (OR 1.4) increased the risk of proximal femoral resection. A sinus tract (OR 9.2) and postoperative dislocation (OR 281.4) were associated with increased risk of subsequent re-revisions.

CONCLUSION

Proximal femoral resection during one-stage revision hip arthroplasty for PJI may be required to reduce the risk of of recurrent or further infection. Patients with additional metalware needing removal or transcortical sinus tracts and chronic osteomyelitis are particularly at higher risk of needing proximal femoral excision. However, radical resection is associated with higher surgical complications and increased re-revision rates. The use of constrained acetabular liners and dual mobility components maintained an acceptable dislocation rate. These results, including identified risk factors, may aid in preoperative planning, patient consultation and consent, and intraoperative decision-making. Cite this article: Bone Joint J 2021;103-B(11):1678-1685.

Structural Factors Associated With Femoral Neck Fractures and its Prediction in Chinese Males

We have recently proposed a new approach to evaluate 2D femoral neck (FN) structure, named the Minimal Model (MM), that comprised FN areal bone mineral density (FNaBMD) and FNWidth and 2 new internal structural measures; (1) the standard deviation of normalized mineral mass projection profile distribution (FNSigma), and (2) the displacement between center-of-mineral mass and geometric center of mineral mass projection profile (FNDelta). The contralateral hip of 67 FN fracture Chinese male patients had a QCT scan shortly after fracture and was compared to 156 community participants without hip fracture. The QCT scans were analyzed using Mindways software to enable DXA-equivalent 2D images to be obtained; MM variables were calculated from these images. In FN fracture and nonfracture participants, the 4 MM variables as well as age, weight and height were compared. Compared to nonfracture, fracture participants were older, weighed less and were taller. After adjustment for these differences FN fracture participants compared to nonfracture had mean ± SD lower FNaBMD 0.54 ± 0.11 vs 0.70 ± 0.11 g/cm² (p < 0.001); larger FNSigma 1.05 ± 0.11 vs 0.98 ± 0.10 cm (p < 0.001); larger FNDelta 0.43 ± 0.09 vs 0.33 ± 0.09 cm (p < 0.001), however FNWidth did not differ 2.96 ± 0.35 vs 2.92 ± 0.34 cm. All variables except FNaBMD and FNWidth were correlated; however logistic regression identified increased age and height, reduced FNaBMD and increased FNSigma as independent contributors to differentiating participants with FN fracture from nonfracture. Area under ROC analysis identified significant improvement in discrimination with addition of FNSigma to the base model of Age and FNaBMD (C statistic 0.88 and 0.91, p = 0.019). These analyses identified important internal structural information available from 2D DXA imaging that contributes to discrimination of FN fracture in addition to low bone mass. This analytical approach may contribute to improved clinical FN fracture prediction, extending value of widely available DXA technology.

External Fixator as a Saviour in the Management of Aneurysmal Bone Cyst with Physeal Extension in Pathological Fracture of the Proximal Femur: A Case Report with a Review of Literature

Introduction:

Aneurysmal bone cysts (ABC’s) are expansile, tumour-like vascular lesion. They are more commonly seen in the metaphyseal region of long bones. They are benign lesion although malignant transformation has been reported. Usually presents in the first three decades of life. Common presentation is pain, swelling, or fracture. Proximal femur with ABC’s is a rare entity and with physeal extension is even sparse.

Case Report:

A 13- year-. old female presented in the orthopaedic emergency with complaints of pain in the right hip region following a trivial fall. Following trauma, the patient was unable to stand or walk. On examination, there was tenderness in Scarpa’s triangle, straight leg raise test was not possible and limb was in external rotation. Plain radiography revealed an inter-trochanteric fracture with cystic lesion in the proximal femur extending till until epiphysis. MRI of the proximal femur showed an air fluid level with septations and soft- tissue oedema suggestive of aneurysmal bone cyst ABC’s.

The patient was managed by intra-lesional curettage with fibular strut grafting along with cancellous bone graft and fixation by Uni-planar external fixator.

Conclusion:

Pathological Fractures fractures of proximal femur management is are a challenge for an orthopaedic surgeon due to its location and biomechanical factors. Treatment of proximal femur ABC’s should be case dependent. In our opinion, aneursymal bone cyst of the proximal femur with physeal extension can be managed by external fixation along with extensive curettage and bone graft.

Case Report: Trans-Articular External Skeletal Fixation of the Hip for a Highly Comminuted Juxta-Articular Fracture of the Proximal Femur Caused by Gunshot Injury in a Cat

This report describes a novel surgical technique for trans-articular external skeletal fixation (TA-ESF) of the hip to stabilize a rare, highly comminuted juxta-articular fracture of the proximal femoral segment involving the metaphysis and diaphysis in a cat. A 2-year-old, castrated male, Korean shorthair cat was admitted for a left femoral fracture caused by gunshot injury. Radiographs and computed tomography (CT) scans revealed a highly comminuted proximal femoral diaphyseal fracture that involved the femoral neck and the greater trochanter. The left femoral head was intact on CT. Under fluoroscopic guidance, an intramedullary Steinmann pin was placed to align the femur, and five positive-profile, end-threaded pins were placed in the left hemipelvis and distal femur. A triangulated frame of connecting bars was constructed using Steinmann pins and epoxy resin for TA-ESF. This secured the pins placed in the pelvis and femur as well as the intramedullary pin, providing proximal femoral stabilization by trans-articular fixation of the hip. The cat began placing weight on the left pelvic limb 4 days postoperatively, and progressively obtained near-normal limb function by day 112. The TA-ESF was partially dismantled to a linear tie-in construct on day 64 and was completely removed on day 161. Final radiographs on day 161 revealed lack of bone healing in the proximal segment, especially femoral head and neck, despite functional recovery of the injured leg. At one year postoperatively, the cat had normal limb function without any noticeable complications. On follow-up 29 months after surgery, the owner reported that the cat had normal limb function without any noticeable complications. Despite insufficient bone healing in the cat, TA-ESF of the hip allowed for satisfactory functional recovery of this challenging juxta-articular fracture of the proximal femur, which was not amenable to stabilization with a traditional non-load-sharing fixation system.

Bone morphology of the proximal femoral canal: ethnicity related differences and the influence on cementless tapered wedge stem designs

BACKGROUND

Differences in proximal femoral morphology between ethnicities may have implications on the design of cementless tapered wedge stems. This study analyses the differences in Asian and Caucasian bone morphology as well as the related fit of various cementless tapered wedge stem designs.

METHODS

A computed tomography database and modelling software was used to retrospectively analyse a total of 1345 femora. Ethnicity related comparisons as well as the fit of the stem designs were analysed.

RESULTS

Statistically significant differences between canal shape of Caucasian and Japanese as well as non-Japanese Asians were observed. The fit of the stems within the femoral canal was highly dependent on the respective stem shape.

CONCLUSIONS

The shape differences in stem designs had a larger influence on the fit within the femoral canal than the differences in ethnicity related to bone morphology.

Proximal Femoral Non-unions with Implant In Situ Treated by Revision Osteosynthesis: A Real Challenge

Introduction:

Proximal femur fractures non-union with implant failure creates a nightmare for both the surgeon and the patient. Meticulous surgical planning and the correct choice of the implant are essential to achieve success in the revision surgery.

Materials and Methods:

Eleven patients with ununited proximal femur fractures including both intertrochanteric and subtrochanteric fractures who had a failed previous implant were included in the study. Femoral neck nonunions and infected nonunions were excluded from the study. One patient was lost to follow-up.

Results:

One patient was lost to follow-up and out of the remaining ten patients, six were males and four were females. Mean age was 62.2 years (35–74). Union was achieved with mean union time of 10.1 months (9–14). Mean surgical time was 105 min (90–125) and mean blood loss during surgery was 600 ml (350–850). Mean time of revision surgery after the primary index surgery was 20 months (15–30). Mean duration of follow-up was 12.9 months (12-16).

Conclusion:

Revision osteosynthesis in proximal femoral nonunions with implant failure is a real test of surgeons expertise because of the many factors going against like osteoporosis, distorted proximal femur anatomy due to the already present implant resulting in poor bone stock availability. Judicious and appropriate selection of implants is an impeccable factor for fracture union and positive outcome.

A modified surgical technique to simplify the procedure of femoral stem implantation for an appropriate anteversion angle during endoprosthetic reconstruction

BACKGROUND

In patients with bone tumors of the proximal femur, endoprosthetic reconstruction can provide stable and durable biological reconstruction. However, it is difficult and time-consuming to accurately place the femoral component for an appropriate anteversion angle after large tumor resection. We propose a modified surgical technique for simplifying the implantation process and promoting the stability of the artificial joint.

METHODS

We retrospectively analyzed the clinical data of 28 patients undergoing endoprosthetic reconstruction at our center between 2009 and 2016. We used a traditional method (group A, n=11) and a modified surgical technique (group B, n=17) to determine the femoral anteversion angle during implantation of the femoral component. The modified surgical technique allowed more convenient and accurate implantation of the femoral components by externally rotating the shin at an angle of 15°. Surgical time and blood loss were designated as the primary outcomes, hospital stays, postoperative complications and functional recovery [Harris Hip Score (HHS); Musculoskeletal Tumor Society Score (MSTS)] were recorded as the secondary outcomes. The outcomes of the two groups were compared to verify the safety and efficacy of the modified surgical technique.

RESULTS

The mean operative time was shorter in group B (109±10 minutes) than group A (131±6 minutes) (P<0.05). Although the average estimated intraoperative blood loss was less in group B (814±35 mL) than that in group A (839±30 mL), there was no significant difference between the two groups (P=0.06). There was no significant difference between the two groups in hospital stays, postoperative complications, HHS or MSTS.

CONCLUSIONS

This modified surgical technique can simplify the process of femoral component implantation and significantly shorten operative time without increasing postoperative complications.

Morphology of Proximal Femur in South-West Coast of India

Introduction

With a higher proportion of young individuals undergoing uncemented hip arthroplasty, a close match in the dimension of the proximal femur and the implanted prosthesis is paramount. This is a study to gain insight into geographical variation in proximal femur morphology to determine the reference values to design uncemented femoral stems for a south Indian population, and also the effect of ageing and gender on the proximal femur morphology.

Materials and Methods

The study comprised of two groups. For the first group, 50 unpaired dry femur bones were obtained from adult human cadavers; and the second group was a clinical group of 50 adult patients. Standardised radiographic techniques were used to measure the extra-cortical and intra-cortical morphometric parameters. Based on these, dimensionless ratios were calculated to express the shape of the proximal femur. The data were expressed in terms of mean and standard deviation and a comparison made with other studies.

Results

A significant difference was noted across various population subsets within the Indian subcontinent and also in comparison to the Western population, suggestive of regional variation. The measurements made in cadaveric bone differed significantly from those in live patients, especially the femoral head diameter and extra-cortical and intra-cortical width. Femoral offset, head height and diameter were significantly less in females.

Conclusion

The south Indian population needs customised implants with an increase in neck shaft angle and a decrease in intra-cortical and extra-cortical width for press fit in hip arthroplasty. The variation between the two sexes must also be accounted for during prosthesis design.

Femoral anteversion: significance and measurement

Femoral neck anteversion (FNA) is the angle between the femoral neck and femoral shaft, indicating the degree of torsion of the femur. Differences in FNA affect the biomechanics of the hip, through alterations in factors such as moment arm lengths and joint loading. Altered gait associated with differences in FNA may also contribute to the development of a wide range of skeletal disorders including osteoarthritis. FNA varies by up to 30° within apparently healthy adults. FNA increases substantially during gestation and thereafter decreases steadily until maturity. There is some evidence of a further decrease at a much lower rate during adulthood into old age, but the mechanisms behind it have never been studied. Development of FNA appears to be strongly influenced by mechanical forces experienced during everyday movements. This is evidenced by large differences in FNA in groups where movement is impaired, such as children born breech or individuals with neuromuscular conditions such as cerebral palsy. Several methods can be used to assess FNA, which may yield different values by up to 20° in the same participant. While MRI and CT are used clinically, limitations such as their cost, scanning time and exposure to ionising radiation limit their applicability in longitudinal and population studies, particularly in children. More broadly, applicable measures such as ultrasound and functional tests exist, but they are limited by poor reliability and validity. These issues highlight the need for a valid and reliable universally accepted method. Treatment for clinically problematic FNA is usually de-rotational osteotomy; passive, non-operative methods do not have any effect. Despite observational evidence for the effects of physical activity on FNA development, the efficacy of targeted physical activity remains unexplored. The aim of this review is to describe the biomechanical and clinical consequences of FNA, factors influencing FNA and the strengths and weaknesses of different methods used to assess FNA.

Are Daily Life Activities of Patients with Proximal Femoral Tumor Resection Prosthesis as Good as those of Patients Undergoing Total Hip Prosthesis for Non-Tumor Causes?

INTRODUCTION

The Barthel Index of Activities of Daily Life (ADL) is a scale used to evaluate performance in daily life activities and investigate the reason and resulting relationships in a comprehensive, non-biased manner.

AIM

The aim of this study was to compare the daily life activities of patients who underwent proximal femoral tumor resection prosthesis assessed by the Barthel Index with the activities of daily living of patients with a total hip prosthesis performed for non-tumor reasons.

MATERIALS AND METHODS

Twenty-eight patients were included in the study. Sixteen patients underwent hip prosthesis for reasons other than tumor (femur proximal avascular necrosis, coxarthrosis, etc.) and 12 underwent wide resection and femur proximal tumor resection prosthesis due to primary malignant bone tumor or metastasis in the proximal femur. The Barthel Index was used to evaluate their life quality at 3 months.

RESULTS

A total of 28 patients (mean age 60.9±1.4 yrs, range 19.0-84.0, 17 female and 11 male patients) were included into the study. Mean ADL score was 84.5±20.6 (5-100.0). While only one patient was totally dependent in terms of daily life activities, 8 other patients were totally independent. When the patient groups were categorized by degree of dependency according to the ADL scores, it was found that dependency states of the two surgery groups were similar in distribution (p=0.212, p=0.703, and p=1.000 respectively).

CONCLUSION

Functional recovering levels were good in the patients who underwent a surgery for proximal femoral tumor resection prosthesis; there was no significant difference when we compared the functional level after total hip prosthesis applied for non-tumor reasons.

Proximal femur sarcomas with intra-articular disease-Do intra-articular resections provide adequate local control?

BACKGROUND AND OBJECTIVES

Hip preserving (intra-articular) resections for proximal femur sarcoma have better function compared to peri-acetabular (extra-articular) resections, which are more complex and morbid. But, do intra-articular resections in selected cases with intra-articular disease provide adequate local control?

METHOD

Extra-articular resection or intra-articular resection in cases without pathologic fracture or away from joint/capsule was classified as a planned safe margin (SM). Circumferential removal of labrum without acetabular resection in cases without gross joint contamination was classified as planned close margins (CM). We analyzed local recurrence-free survival (LRFS) (death as a competing event) for 86 proximal femur resections (SM = 55, CM = 31).

RESULTS

The 5 years LRFS was 84% (n = 6/55, 10%) in the SM group and 67% (n = 4/31, 12%) in the CM group. There was no worsening of local recurrence (LR) in the CM group (subdistribution hazard [sH] = 0.69; 95% confidence interval [CI], 0.21-2.29; P = .56). Poor chemotherapy-induced necrosis predicted worse LR (sH = 0.1; 95% CI, 0.01-0.8; P = .03). Overall survival was 16% (SE 8%) at 5 years with LR vs 64% (SE 7%) without LR (P = .0076).

CONCLUSION

In proximal femur sarcomas with potential for involvement of the hip joint, a CM in selected cases did not worsen LR; providing an option for avoiding additional morbidity with extra-articular resections.

Hip Fracture Prevention in Osteoporotic Elderly and Cancer Patients: An On-Line French Survey Evaluating Current Needs

Background and objectives: Hip fracture is a major public health issue. Those fractures lead to high costs and a decrease in quality of life. A national French survey was conducted, with the objectives to firstly assess the current management of hip fracture and its prevention, both in the osteoporotic and cancer settings, and secondly to evaluate the opinions of physicians on the potential use of minimally invasive implantable devices to prevent hip fracture in alternative of surgery. Materials and methods: This national survey was conducted in France between April and July 2017. Questionnaires were sent to orthopedic surgeons, interventional radiologists, oncologists, and rheumatologists. Completed questionnaires were analyzed and compared according to two indications: orthopedics-traumatology and oncology. Factors associated with these responses were assessed using univariable analyses, based on chi-square tests or an exact Fisher test, as appropriate. Results: A total of 182 questionnaires were completed and further analyzed. Physicians have highlighted the need for a low re-fracture rate and to improve life expectancy for more than 1 year (50% for responders of the orthopedics-traumatology questionnaire and 80% for the responders interested in both indications), as well as quality of life (12.5% and 31%, respectively), but with no significant differences in the oncologic indication. Most of the experts were willing to use or prescribe implantable devices for prevention (63% in orthopedics-traumatology and 93% in oncology), although limited clinical experience (54 and 58%) and surgical risk (around 30% in each indication) were considered as limits. Conclusions: Prevention of hip fracture remains a concern for physicians. More clinical experience with implantable devices, in particular in cancer patients, is needed, but implemented in a strategy to maximize patient recovery while reducing costs.

The influence of loading configurations on numerical evaluation of failure mechanisms in an uncemented femoral prosthesis

The clinical relevance of numerical predictions of failure mechanisms in femoral prosthesis could be impaired due to simplification of musculoskeletal loading. This study investigated the extent to which loading configurations affect the preclinical analysis of an uncemented femoral implant. Patient-specific, CT-scan based FE models of intact and implanted femurs were developed and analysed using three loading configurations, which comprised of load cases representing daily activities. First loading configuration consisted of two load cases, each of walking and stair climbing. The second consisted of more number of load cases for each of these activities. The third included load cases of additional activities of standing up and sitting down. Failure criteria included maximum principal strains, interface debonding, implant-bone relative displacement and adaptive bone remodelling. Simplified loading configurations led to a reduction (100-1500 με) around cortical principal strains. The area prone to interface debonding were observed in the proximo-medial part of implant and was maximum when all activities were considered. This area was reduced by 35%, when simplified loading configurations were chosen. Interfacial area of 88%-96% experienced implant-bone relative displacements below 40 μm; however maximum of 110 μm was observed at the calcar region. Lack of consideration of variety of activities overestimated (30%-50%) bone resorption around the lateral part of the implant; hence, these bone remodelling results were less clinically relevant. Considering a variety daily activities along with an adequate number of load cases for each activity seemed necessary for pre-clinical evaluations of reconstructed femur.

Treatment of bone loss in proximal femurs of postmenopausal osteoporotic women with AGN1 local osteo-enhancement procedure (LOEP) increases hip bone mineral density and hip strength: a long-term prospective cohort study

This first-in-human study of AGN1 LOEP demonstrated that this minimally-invasive treatment durably increased aBMD in femurs of osteoporotic postmenopausal women. AGN1 resorption was coupled with new bone formation by 12 weeks and that new bone was maintained for at least 5-7 years resulting in substantially increased FEA-estimated femoral strength.

INTRODUCTION

This first-in-human study evaluated feasibility, safety, and in vivo response to treating proximal femurs of postmenopausal osteoporotic women with a minimally-invasive local osteo-enhancement procedure (LOEP) to inject a resorbable triphasic osteoconductive implant material (AGN1).

METHODS

This prospective cohort study enrolled 12 postmenopausal osteoporotic (femoral neck T-score ≤ - 2.5) women aged 56 to 89 years. AGN1 LOEP was performed on left femurs; right femurs were untreated controls. Subjects were followed-up for 5-7 years. Outcomes included adverse events, proximal femur areal bone mineral density (aBMD), AGN1 resorption, and replacement with bone by X-ray and CT, and finite element analysis (FEA) estimated hip strength.

RESULTS

Baseline treated and control femoral neck aBMD was equivalent. Treated femoral neck aBMD increased by 68 ± 22%, 59 ± 24%, and 58 ± 27% over control at 12 and 24 weeks and 5-7 years, respectively (p < 0.001, all time points). Using conservative assumptions, FEA-estimated femoral strength increased by 41%, 37%, and 22% at 12 and 24 weeks and 5-7 years, respectively (p < 0.01, all time points). Qualitative analysis of X-ray and CT scans demonstrated that AGN1 resorption and replacement with bone was nearly complete by 24 weeks. By 5-7 years, AGN1 appeared to be fully resorbed and replaced with bone integrated with surrounding trabecular and cortical bone. No procedure- or device-related serious adverse events (SAEs) occurred.

CONCLUSIONS

Treating femurs of postmenopausal osteoporotic women with AGN1 LOEP results in a rapid, durable increase in aBMD and femoral strength. These results support the use and further clinical study of this approach in osteoporotic patients at high risk of hip fracture.

Pathologic Versus Native Hip Fractures: Comparing 30-day Mortality and Short-term Complication Profiles

BACKGROUND

A large body of research on native hip fractures has resulted in several evidence-based guidelines aimed at improving postsurgical care for these patients. In contrast, there is a paucity of data on pathologic hip fractures, and whether native hip fracture protocols are generalizable to this population is unknown. The purpose of this study was to compare mortality rates and complication profiles between patients with pathologic and native hip fractures.

METHODS

Using the American College of Surgeons-National Surgical Quality Improvement Program (NSQIP) database, we identified patients who underwent surgical treatment for pathologic and native hip fractures from 2007 to 2017 and 2601 matched pairs were identified using propensity scoring. Baseline covariates were controlled for, and rates of 30-day postoperative complications and mortality were compared using McNemar's test.

RESULTS

Pathologic hip fracture patients experienced significantly higher rates of death (6.3% vs 4.3%, P < .001), serious adverse events (17.3% vs 13.5%, P < .001), minor complications (34.3% vs 29.1%, P < .001), extended postoperative lengths of stay (30.2% vs 25.9%, P < .001), readmissions (11.9% vs 8.4%, P < .001), thromboembolic complications (3.0% vs 1.6%, P < .001), and perioperative transfusions (31.5% vs 26.4%, P < .001) compared to native hip fracture patients.

CONCLUSION

Pathologic hip fractures result in significantly higher complication rates than native hip fractures after surgical treatment, suggesting that guidelines for native hip fractures may not be generalizable for pathologic hip fractures. Orthopedic surgeons should closely monitor these patients for deep vein thrombosis, utilize blood sparing techniques, and employ a multidisciplinary approach to help manage and prevent a more heterogenous profile of postsurgical complications.

Shepherd's crook deformity: How to set it straight. A five-step surgical guide

PURPOSE

Fibrous dysplasia (FD) of the proximal femur can result in severe deformity and disability. The results of surgical management in such situations have been reported to be poor. We present a novel, five-step surgical treatment to correct proximal femoral deformity in FD.

MATERIAL AND METHODS

This study is a review of prospectively collected data of cases of proximal femur polyostotic FD managed at our institute from 2012 onward. We managed three patients with FD involving four femora (one patient had bilateral disease). Mean age at presentation was 16 years with an average follow-up of 46 months. All underwent five steps, that is, (1) curettage/excision of the lesion, (2) allograft in intramedullary region, (3) lateral closing wedge valgus osteotomy, (4) fixation with extramedullary implant, and (5) augmentation of osteotomy site with autograft. Functional outcome was assessed using Harris Hip Score preoperatively and at the final follow-up.

RESULTS

The neck shaft angle was corrected from an average of 91.7° to 152.1°, while the Harris Hip Score improved from an average of 59 to 95. There was no clinical or radiological evidence of recurrence of disease or deformity in any patient till the last follow-up.

CONCLUSION

This five-step technique ensures good functional and radiological outcomes in the management of proximal femur FD.

En-Bloc Resection of Metastases of the Proximal Femur and Reconstruction by Modular Arthroplasty is Not Only Justified in Patients with a Curative Treatment Option-An Observational Study of a Consecutive Series of 45 Patients

Background: There is little conformity regarding the surgical treatment of metastasis of the proximal femur, especially in palliative patients with limited life expectancy. Patients and Methods: En-bloc resection of secondary bone malignancies of the proximal femur and reconstruction by modular arthroplasty was performed in a consecutive series of 45 patients. The mean follow-up period was 16.4 months (0.6–74.7). Results: The survival rate of all patients was 6.6% (95% CI: 0–14.9) at 74.7 months. There was no significant difference in patients with a solitary or disseminated disease at index operation (log-rank p = 0.1214). Recurrent dislocation was the most frequent local complication (n = 6) necessitating an open reduction in four cases. The use of a Trevira tube showed a higher risk of dislocation compared to the simple bonding of remaining soft tissue (6 out of 28 vs. 0 out of 17; Fisher test: p = 0.0463). The worst-case survival rate with the removal of the arthroplasty for any cause and/or loss to follow-up was 80.0% (95% CI: 44.9–100) at 74.7 months (n = 1 due to low-grade infection). Conclusions: En-bloc resection of metastases and reconstruction by modular arthroplasty is reliable even in patients with very limited life expectancy. Local complications due to tumor growth or instability after intralesional surgery could be managed successfully but recurrent dislocation as the most frequent complication has to be taken into account. The simple bonding of remaining soft tissue around the prosthesis without the use of an attachment tube may reduce the dislocation rate and reoperation risk.

Adaptation of Proximal Femur to Mechanical Loading in Young Adults: Standard Vs Localized Regions Evaluated by DXA

Regions of the proximal femur with less adaptive protection by mechanical loading may be at increased risk of structural failure. Since the size and location of these regions diverge from those defined by the dual-energy X-ray absorptiometry manufacturers the purpose of this study was to compare areal bone mineral density (aBMD) of different regions of the proximal femur considering impact loads from physical activity (PA). The participants were 134 young adults divided into 2 groups according to the impact of PA performed in the last 12 mo: high-impact PA and low-impact PA. The aBMD of the proximal femur was assessed by dual-energy X-ray absorptiometry at the standard femoral neck, intertrochanter, and trochanter, and at specific locations of the superolateral femoral neck and intertrochanteric region. The bone-specific physical activity questionnaire was used to estimate the impact load of PA. Comparisons between groups were adjusted for body height and body lean mass. Interaction analysis between sex and PA groups were conducted with analysis of variance. Comparisons of aBMD between bone regions were analyzed separately for men and women with repeated measures analysis of variance. In the high-impact PA group, men benefit more than women at all bone regions, except the aBMD at intertrochanteric region. Analyses of repeated measures did not reveal any significant interaction effect between bone regions (standard vs specific) and PA groups (low vs high-impact). In conclusion, aBMD differences due to mechanical loading were more pronounced in men than in women; the magnitude of the aBMD differences as a result of different levels of PA was similar between standard and localized regions.