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Nguyen HH, Le DT, Shore-Lorenti C, Chen C, Schilcher J, Eklund A, Zebaze R, Milat F, Sztal-Mazer S, Girgis CM, Clifton-Bligh R, Cai J, Ebeling PR. AFFnet - a deep convolutional neural network for the detection of atypical femur fractures from anteriorposterior radiographs. Bone 2024; 187:117215. [PMID: 39074569 DOI: 10.1016/j.bone.2024.117215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Revised: 07/14/2024] [Accepted: 07/26/2024] [Indexed: 07/31/2024]
Abstract
Despite well-defined criteria for radiographic diagnosis of atypical femur fractures (AFFs), missed and delayed diagnosis is common. An AFF diagnostic software could provide timely AFF detection to prevent progression of incomplete or development of contralateral AFFs. In this study, we investigated the ability for an artificial intelligence (AI)-based application, using deep learning models (DLMs), particularly convolutional neural networks (CNNs), to detect AFFs from femoral radiographs. A labelled Australian dataset of pre-operative complete AFF (cAFF), incomplete AFF (iAFF), typical femoral shaft fracture (TFF), and non-fractured femoral (NFF) X-ray images in anterior-posterior view were used for training (N = 213, 49, 394, 1359, respectively). An AFFnet model was developed using a pretrained (ImageNet dataset) ResNet-50 backbone, and a novel Box Attention Guide (BAG) module to guide the model's scanning patterns to enhance its learning. All images were used to train and internally test the model using a 5-fold cross validation approach, and further validated by an external dataset. External validation of the model's performance was conducted on a Sweden dataset comprising 733 TFF and 290 AFF images. Precision, sensitivity, specificity, F1-score and AUC were measured and compared between AFFnet and a global approach with ResNet-50. Excellent diagnostic performance was recorded in both models (all AUC >0.97), however AFFnet recorded lower number of prediction errors, and improved sensitivity, F1-score and precision compared to ResNet-50 in both internal and external testing. Sensitivity in the detection of iAFF was higher for AFFnet than ResNet-50 (82 % vs 56 %). In conclusion, AFFnet achieved excellent diagnostic performance on internal and external validation, which was superior to a pre-existing model. Accurate AI-based AFF diagnostic software has the potential to improve AFF diagnosis, reduce radiologist error, and allow urgent intervention, thus improving patient outcomes.
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Affiliation(s)
- Hanh H Nguyen
- Department of Medicine, School of Clinical Sciences, Monash University, Victoria, Australia; Department of Endocrinology, Monash Health, Victoria, Australia; Department of Endocrinology and Diabetes, Western Health, Victoria, Australia; Department of Medicine, The University of Melbourne, Victoria, Australia.
| | - Duy Tho Le
- Department of Medicine, School of Clinical Sciences, Monash University, Victoria, Australia; Department of Information Technology, Monash University, Victoria, Australia
| | - Cat Shore-Lorenti
- Department of Medicine, School of Clinical Sciences, Monash University, Victoria, Australia
| | - Colin Chen
- Department of Medicine, School of Clinical Sciences, Monash University, Victoria, Australia
| | - Jorg Schilcher
- Department of Biomedical and Clinical Sciences, and the Wallenberg Centre for Molecular Medicine, Linköping University, Linköping, Sweden
| | - Anders Eklund
- Department of Biomedical Engineering, Linköping University, Linköping, Sweden
| | - Roger Zebaze
- Department of Medicine, School of Clinical Sciences, Monash University, Victoria, Australia
| | - Frances Milat
- Department of Medicine, School of Clinical Sciences, Monash University, Victoria, Australia; Department of Endocrinology, Monash Health, Victoria, Australia
| | - Shoshana Sztal-Mazer
- Department of Endocrinology and Diabetes, Alfred Health, Victoria, Australia; Department of Public Health and Preventative Medicine, Monash University, Melbourne, Australia
| | - Christian M Girgis
- Department of Endocrinology, Royal North Shore Hospital, New South Wales, Australia; Department of Diabetes and Endocrinology, Westmead Hospital, New South Wales, Australia; Faculty of Medicine and Health, The University of Sydney, New South Wales, Australia
| | - Roderick Clifton-Bligh
- Department of Endocrinology, Royal North Shore Hospital, New South Wales, Australia; Department of Diabetes and Endocrinology, Westmead Hospital, New South Wales, Australia
| | - Jianfei Cai
- Department of Information Technology, Monash University, Victoria, Australia
| | - Peter R Ebeling
- Department of Medicine, School of Clinical Sciences, Monash University, Victoria, Australia; Department of Endocrinology, Monash Health, Victoria, Australia
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Schilcher J, Nilsson A, Andlid O, Eklund A. Fusion of electronic health records and radiographic images for a multimodal deep learning prediction model of atypical femur fractures. Comput Biol Med 2024; 168:107704. [PMID: 37980797 DOI: 10.1016/j.compbiomed.2023.107704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 10/15/2023] [Accepted: 11/07/2023] [Indexed: 11/21/2023]
Abstract
Atypical femur fractures (AFF) represent a very rare type of fracture that can be difficult to discriminate radiologically from normal femur fractures (NFF). AFFs are associated with drugs that are administered to prevent osteoporosis-related fragility fractures, which are highly prevalent in the elderly population. Given that these fractures are rare and the radiologic changes are subtle currently only 7% of AFFs are correctly identified, which hinders adequate treatment for most patients with AFF. Deep learning models could be trained to classify automatically a fracture as AFF or NFF, thereby assisting radiologists in detecting these rare fractures. Historically, for this classification task, only imaging data have been used, using convolutional neural networks (CNN) or vision transformers applied to radiographs. However, to mimic situations in which all available data are used to arrive at a diagnosis, we adopted an approach of deep learning that is based on the integration of image data and tabular data (from electronic health records) for 159 patients with AFF and 914 patients with NFF. We hypothesized that the combinatorial data, compiled from all the radiology departments of 72 hospitals in Sweden and the Swedish National Patient Register, would improve classification accuracy, as compared to using only one modality. At the patient level, the area under the ROC curve (AUC) increased from 0.966 to 0.987 when using the integrated set of imaging data and seven pre-selected variables, as compared to only using imaging data. More importantly, the sensitivity increased from 0.796 to 0.903. We found a greater impact of data fusion when only a randomly selected subset of available images was used to make the image and tabular data more balanced for each patient. The AUC then increased from 0.949 to 0.984, and the sensitivity increased from 0.727 to 0.849. These AUC improvements are not large, mainly because of the already excellent performance of the CNN (AUC of 0.966) when only images are used. However, the improvement is clinically highly relevant considering the importance of accuracy in medical diagnostics. We expect an even greater effect when imaging data from a clinical workflow, comprising a more diverse set of diagnostic images, are used.
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Affiliation(s)
- Jörg Schilcher
- Department of Orthopedics and Experimental and Clinical Medicine, Faculty of Health Science, Linköping University, Linköping, Sweden; Wallenberg Centre for Molecular Medicine, Linköping University, Linköping, Sweden; Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
| | - Alva Nilsson
- Department of Biomedical Engineering, Linköping University, Linköping, Sweden
| | - Oliver Andlid
- Department of Biomedical Engineering, Linköping University, Linköping, Sweden
| | - Anders Eklund
- Department of Biomedical Engineering, Linköping University, Linköping, Sweden; Division of Statistics and Machine Learning, Department of Computer and Information Science, Linköping University, Linköping, Sweden; Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden.
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Dadrewalla AJ, Battle J, Anakwe R. Case Report - Short-term Bisphosphonate Use Associated Stress Fractures. J Orthop Case Rep 2022; 12:78-82. [PMID: 36874892 PMCID: PMC9983371 DOI: 10.13107/jocr.2022.v12.i10.3376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 08/29/2022] [Indexed: 01/19/2023] Open
Abstract
Introduction Long-term bisphosphonate use has been linked to an increased risk of pathological neck of femur fractures. Case Report We write concerning a patient who presented with the left hip pain following a low impact fall, which was diagnosed as a pathological left neck of femur fracture. This was a subtrochanteric stress fracture most frequently seen in patients who take bisphosphonate medications. A key point of difference in our patient is the length of time of bisphosphonate use. A further interesting point was the method of imaging used to diagnose this fracture whereby plain radiographs and computerized tomography imaging both did not show any acute fracture whereas only a magnetic resonance imaging (MRI) hip demonstrated this fracture. Surgical insertion of a prophylactic intramedullary nail was done to stabilize the fracture and reduce the risk of progression to a complete fracture. Conclusion This case brings up multiple key points not reviewed previously such as the fact a fracture developed only 1 month after bisphosphonate use rather than months or years. These points suggest that there should be a low threshold for investigation (including MRI scanning) into potential pathological fractures and that bisphosphonate use should be a red flag to initiate these investigations regardless of length of use.
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Affiliation(s)
- Arshan J Dadrewalla
- Imperial College Healthcare Trust, St Mary's Hospital, Praed St, London W2 1NY
| | - Joseph Battle
- Imperial College Healthcare Trust, St Mary's Hospital, Praed St, London W2 1NY
| | - Raymond Anakwe
- Imperial College Healthcare Trust, St Mary's Hospital, Praed St, London W2 1NY
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BÖGL HP, ZDOLSEK G, BARNISIN L, MÖLLER M, SCHILCHER J. Surveillance of atypical femoral fractures in a nationwide fracture register. Acta Orthop 2022; 93:229-233. [PMID: 35019144 PMCID: PMC8815300 DOI: 10.2340/17453674.2022.1380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Indexed: 01/31/2023] Open
Abstract
Background and purpose - To continuously assess the incidence of atypical femoral fractures (AFFs) in the population is important, to allow the evaluation of the risks and benefits associated with osteoporosis treatment. Therefore, we investigated the possibility to use the Swedish Fracture Register (SFR) as a surveillance tool for AFFs in the population and to explore means of improvement. Patients and methods - All AFF registrations in the SFR from January 1, 2015 to December 31, 2018 were enrolled in the study. For these patients, radiographs were obtained and combined with radiographs from 176 patients with normal femoral fractures, to form the study cohort. All images were reviewed and classified into AFFs or normal femur fractures by 2 experts in the field (gold-standard classification) and 1 orthopedic resident educated on the specific radiographic features of AFF (educated-user classification). Furthermore, we estimated the incidence rate of AFFs in the population captured by the register through comparison with a previous cohort and calculated the positive predictive value (PPV) and, where possible, the inter-observer agreement (Cohen's kappa) between the different classifications. Results - Of the 178 available patients with AFF in the SFR, 104 patients were classified as AFF using the goldstandard classification, and 89 using the educated-user classification. The PPV increased from 0.58 in the SFR classification to 0.93 in the educated-user classification. The interobserver agreement between the gold-standard classification and the educated-user classification was 0.81. Interpretation - With a positive predictive value of 0.58 the Swedish Fracture Register outperforms radiology reports and reports to the Swedish Medical Products Agency on adverse drug reactions as a diagnostic tool to identify atypical femoral fractures.
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Affiliation(s)
- Hans Peter BÖGL
- Department of Orthopedic Surgery, Gävle Hospital, Gävle,Department of Orthopedic Surgery and Department of Biomedical and Clinical Sciences, Linköping University, Linköping and Center for Medical Image Science and Visualization, Linköping University, Linköping
| | - Georg ZDOLSEK
- Department of Orthopedic Surgery and Department of Biomedical and Clinical Sciences, Linköping University, Linköping and Center for Medical Image Science and Visualization, Linköping University, Linköping
| | - Lukas BARNISIN
- Department of Orthopedics, Sahlgrenska University Hospital, Gothenburg
| | - Michael MÖLLER
- Department of Orthopedics, Sahlgrenska University Hospital, Gothenburg,Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Jörg SCHILCHER
- Department of Orthopedic Surgery and Department of Biomedical and Clinical Sciences, Linköping University, Linköping and Center for Medical Image Science and Visualization, Linköping University, Linköping,Wallenberg Centre for Molecular Medicine, Linköping University, Linköping
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Jeong SY, Hwang KT, Oh CW, Kim JW, Sohn OJ, Kim JW, Cho YH, Park KC. Mid-term outcomes after the surgical treatment of atypical femoral fractures : minimum three-year follow-up. Bone Joint J 2021; 103-B:1648-1655. [PMID: 34719278 DOI: 10.1302/0301-620x.103b11.bjj-2021-0416.r1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
AIMS The incidence of atypical femoral fractures (AFFs) continues to increase. However, there are currently few long-term studies on the complications of AFFs and factors affecting them. Therefore, we attempted to investigate the outcomes, complications, and risk factors for complication through mid-term follow-up of more than three years. METHODS From January 2003 to January 2016, 305 patients who underwent surgery for AFFs at six hospitals were enrolled. After exclusion, a total of 147 patients were included with a mean age of 71.6 years (48 to 89) and 146 of whom were female. We retrospectively evaluated medical records, and reviewed radiographs to investigate the fracture site, femur bowing angle, presence of delayed union or nonunion, contralateral AFFs, and peri-implant fracture. A statistical analysis was performed to identify the significance of associated factors. RESULTS The mean follow-up period was 70.2 months (36 to 191). There were 146 AFFs (99.3%) in female patients and the mean age was 71.6 years (48 to 89). The AFFs were located in the subtrochanter and shaft in 52 cases (35.4%) and 95 (64.6%), respectively. The preoperative mean anterior/lateral femoral bowing angles were 10.5° (SD 5.7°)/6.1° (SD 6.2°). The postoperative mean anterior/lateral bowing values were changed by 8.7° (SD 5.4°)/4.6° (SD 5.9°). Bisphosphonates had been used contemporarily in 115 AFFs (78.2%) for a mean of 52.4 months (1 to 204; SD 45.5) preoperatively. Nailing was performed in 133 AFFs (90.5%), and union was obtained at a mean of 23.6 weeks (7 to 85). Delayed union occurred in 41 (27.9%), and nonunion occurred in 13 (8.8%). Contralateral AFF occurred in 79 patients (53.7%), and the use of a bisphosphonate significantly influenced the occurrence of contralateral AFFs (p = 0.019). Peri-implant fractures occurred in a total of 13 patients (8.8%), and a significant increase was observed in cases with plating (p = 0.021) and high grade of postoperative anterolateral bowing (p = 0.044). CONCLUSION The use of a bisphosphonate was found to be a risk factor for contralateral AFF, and high-grade postoperative anterolateral bowing and plate fixation significantly increased the occurrence of peri-implant fractures. Long-term follow-up studies on the bilaterality of AFFs and peri-implant fractures are warranted. Cite this article: Bone Joint J 2021;103-B(11):1648-1655.
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Affiliation(s)
- Soo-Young Jeong
- Department of Orthopedic Surgery, Hanyang University Guri Hospital, Guri, South Korea
| | - Kyu-Tae Hwang
- Orthopedic Surgery, Hanyang University College of Medicine, Seoul, South Korea
| | - Chang-Wug Oh
- Department of Orthopedic Surgery, Kyungpook National University Hospital, Daegu, South Korea
| | - Joon-Woo Kim
- Department of Orthopedic Surgery, Kyungpook National University Hospital, Daegu, South Korea
| | | | - Ji Wan Kim
- Department of Orthopaedic Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
| | | | - Ki Chul Park
- Department of Orthopedic Surgery, Hanyang University Guri Hospital, Guri, South Korea
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Zdolsek G, Chen Y, Bögl HP, Wang C, Woisetschläger M, Schilcher J. Deep neural networks with promising diagnostic accuracy for the classification of atypical femoral fractures. Acta Orthop 2021; 92:394-400. [PMID: 33627045 PMCID: PMC8381921 DOI: 10.1080/17453674.2021.1891512] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Background and purpose - A correct diagnosis is essential for the appropriate treatment of patients with atypical femoral fractures (AFFs). The diagnostic accuracy of radiographs with standard radiology reports is very poor. We derived a diagnostic algorithm that uses deep neural networks to enable clinicians to discriminate AFFs from normal femur fractures (NFFs) on conventional radiographs.Patients and methods - We entered 433 radiographs from 149 patients with complete AFF and 549 radiographs from 224 patients with NFF into a convolutional neural network (CNN) that acts as a core classifier in an automated pathway and a manual intervention pathway (manual improvement of image orientation). We tested several deep neural network structures (i.e., VGG19, InceptionV3, and ResNet) to identify the network with the highest diagnostic accuracy for distinguishing AFF from NFF. We applied a transfer learning technique and used 5-fold cross-validation and class activation mapping to evaluate the diagnostic accuracy.Results - In the automated pathway, ResNet50 had the highest diagnostic accuracy, with a mean of 91% (SD 1.3), as compared with 83% (SD 1.6) for VGG19, and 89% (SD 2.5) for InceptionV3. The corresponding accuracy levels for the intervention pathway were 94% (SD 2.0), 92% (2.7), and 93% (3.7), respectively. With regards to sensitivity and specificity, ResNet outperformed the other networks with a mean AUC (area under the curve) value of 0.94 (SD 0.01) and surpassed the accuracy of clinical diagnostics.Interpretation - Artificial intelligence systems show excellent diagnostic accuracies for the rare fracture type of AFF in an experimental setting.
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Affiliation(s)
- Georg Zdolsek
- Department of Orthopedics and Department of Biomedical and Clinical Sciences, Faculty of Health Science, Linköping University, Linköping;;
| | - Yupei Chen
- Department of Biomedical Engineering and Health Systems, Royal Institute of Technology, Stockholm;
| | - Hans-Peter Bögl
- Department of Orthopedics and Department of Biomedical and Clinical Sciences, Faculty of Health Science, Linköping University, Linköping;; ,Department of Orthopedic Surgery, Gävle Hospital;
| | - Chunliang Wang
- Department of Orthopedics and Department of Biomedical and Clinical Sciences, Faculty of Health Science, Linköping University, Linköping;;
| | - Mischa Woisetschläger
- Department of Radiology and Department of Medical and Health Sciences, Linköping; ,Center for Medical Image Science and Visualization, Linköping University, Linköping;
| | - Jörg Schilcher
- Department of Orthopedics and Department of Biomedical and Clinical Sciences, Faculty of Health Science, Linköping University, Linköping;; ,Wallenberg Centre for Molecular Medicine, Linköping University, Linköping, Sweden,Correspondence:
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Celii FG, Beckmann NM. Radiation-induced insufficiency fracture of the femur 18 years after radiation therapy. Radiol Case Rep 2019; 14:179-183. [PMID: 30425769 PMCID: PMC6226624 DOI: 10.1016/j.radcr.2018.10.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 10/26/2018] [Indexed: 11/24/2022] Open
Abstract
Advances in oncologic treatment have improved survival rates, allowing late effects of radiotherapy to become more prevalent. Our patient, an 82-year-old woman with a remote history of right thigh basal cell carcinoma treated with resection and radiation therapy 18 years prior, presented with severe right thigh pain and inability to bear weight as she had suffered a femur fracture after a fall from standing. Initial imaging was suspicious for pathologic fracture secondary to malignancy due to imaging findings and because radiation-induced fractures have rarely been reported beyond 44 months from treatment. However, upon further imaging, evidence pointed to radiation-induced osteonecrosis as the mechanism for her insufficiency fracture. This case highlights the permanent deleterious effects of radiation therapy on bone, and the prudence of considering radiation-induced osteonecrosis as a mechanism of injury in low-energy trauma even long after radiation therapy. In addition, the case serves to review the natural history of irradiated bone injury and pertinent imaging findings.
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Affiliation(s)
| | - Nicholas M. Beckmann
- Department of Diagnostic and Interventional Imaging, University of Texas Health Science Center-McGovern School of Medicine, 6431 Fannin Street, 2.130B, Houston, TX 77030 USA
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Abstract
PURPOSE OF REVIEW To summarize reports published since the 2013 American Society of Bone and Mineral Research Task Force Report on atypical femoral fractures (AFF). RECENT FINDINGS The absolute incidence of AFFs remains low. AFFs are primarily associated with prolonged bisphosphonate (BP) exposure, but have also been reported in unexposed patients and those receiving denosumab for osteoporosis and metastatic bone disease. Asians may be more susceptible to AFFs. Lateral femoral bowing and varus hip geometry, which increase loading forces on the lateral femoral cortex, may increase AFF risk. Altered bone material properties associated with BP therapy may predispose to AFFs by permitting initiation and increasing propagation of micro-cracks. Relevant genetic mutations have been reported in patients with AFFs. Single X-ray absorptiometry femur scans permit early detection of incomplete and/or asymptomatic AFFs. Orthopedists recommend intramedullary rods for complete AFFs and for incomplete, radiologically advanced AFFs associated with pain and/or marrow edema on MRI. Teriparatide may advance AFF healing but few data support its efficacy. Greater understanding of biological and genetic predisposition to AFF may allow characterization of individual risk prior to initiating osteoporosis therapy and help allay fear in those at low risk for this complication, which remains rare in comparison to the osteoporotic fractures prevented by antiresorptive therapy.
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Affiliation(s)
- Jessica Starr
- Division of Endocrinology, Department of Medicine, Columbia University Irving Medical Center, 180 Fort Washington Avenue, Room 9-910, New York, NY, 10032, USA
| | | | - Elizabeth Shane
- Division of Endocrinology, Department of Medicine, Columbia University Irving Medical Center, 180 Fort Washington Avenue, Room 9-910, New York, NY, 10032, USA.
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Pedrazzoni M, Giusti A, Girasole G, Abbate B, Verzicco I, Cervellin G. Atypical femoral fractures in Italy: a retrospective analysis in a large urban emergency department during a 7-year period (2007-2013). J Bone Miner Metab 2017; 35:562-570. [PMID: 27830385 DOI: 10.1007/s00774-016-0790-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 09/20/2016] [Indexed: 10/20/2022]
Abstract
The aim of this study was to determine the incidence of atypical femoral fractures (AFFs) seen in a large emergency department in Italy. It was a retrospective study of all men and women aged 40 years or older admitted to the Emergency Department of Parma University Hospital for a femoral fracture. Cases were identified in the hospital database with use of International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) code 820 or 821 or text strings. All the radiographic images of fractures not clearly identified as proximal or condylar were retrieved and evaluated by three independent reviewers. Fractures were considered as atypical if all three reviewers agreed on at least four of five major features defined by the 2013 American Society for Bone and Mineral Research criteria. In the 7-year period (2007-2013), with a total follow-up of 1,383,154 patient-years, we found 22 AFFs in 21 patients, accounting for 7.1% of low-trauma subtrochanteric/femoral shaft fractures and 0.6% of all femoral fractures. The incidence was very low (1.6 in 100,000 patient-years in both sexes combined). In contrast, the incidence of classic fractures of the proximal end of the femur was at least two orders of magnitude higher (typical/atypical rate ratio 152). Bisphosphonate use was reported in 13 patients (62%; mean treatment duration 9 years; range 5-14 years). Among 286 patients with typical subtrochanteric/femoral shaft fractures, 20 were being treated with bisphosphonate (7%; odds ratio 22; 95% confidence interval 8-58; p < 0.001). This study confirms the very low incidence of AFFs in the largest Italian cohort of patients to date. Even though the risk is higher in patients treated with bisphosphonates, AFFs are very rare, and typical femoral fractures are at least 100-fold more frequent.
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Affiliation(s)
- Mario Pedrazzoni
- Department of Clinical and Experimental Medicine, University of Parma, Via Gramsci 14, 43126, Parma, Italy.
| | - Andrea Giusti
- Bone Clinic, Department of Geriatric Care, Ortho-Geriatrics and Rehabilitation, Galliera Hospital, Genoa, Italy
| | | | - Barbara Abbate
- Department of Clinical and Experimental Medicine, University of Parma, Via Gramsci 14, 43126, Parma, Italy
| | - Ignazio Verzicco
- Department of Clinical and Experimental Medicine, University of Parma, Via Gramsci 14, 43126, Parma, Italy
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Qiu S, Divine GW, Palnitkar S, Kulkarni P, Guthrie TS, Honasoge M, Rao SD. Bone Structure and Turnover Status in Postmenopausal Women with Atypical Femur Fracture After Prolonged Bisphosphonate Therapy. Calcif Tissue Int 2017; 100:235-243. [PMID: 28013363 PMCID: PMC5315598 DOI: 10.1007/s00223-016-0223-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2016] [Accepted: 12/16/2016] [Indexed: 12/31/2022]
Abstract
Atypical femur fracture (AFF), a serious complication of long-term bisphosphonate therapy, is usually preceded by an incomplete fracture appearing on the lateral femur. AFF is most likely the result of severely suppressed bone turnover (SSBT). However, the differences in bone structure and turnover between patients with incomplete and complete AFF remain unknown. We examined trans-iliac bone biopsies from 12 white postmenopausal women with AFF (incomplete = 5; complete = 7) on BP therapy of >5 years and 43 healthy white premenopausal women. Histomorphometric measurements were performed separately in cancellous, intracortical and endosteal envelopes. Of the 43 histomorphometric measurements on 3 difference bone surfaces (cancellous, intracortical and endosteal), only 2 bone resorption variables (Oc.S/BS and Oc.S/NOS) on the endosteal surface were significantly lower in patients with complete AFF than those with incomplete AFF. Compared to healthy premenopausal women, the trabecular bone volume, thickness and number were all significantly lower in patients with AFF. The dynamic bone formation variables in patients with AFF were significantly reduced on all bone surfaces. The likelihood of a biopsy with no tetracycline labeling was significantly higher in AFF patients than in healthy premenopausal women. Based on these results, we conclude that there are no significant differences in bone turnover between patients with incomplete and complete AFF, suggesting that the suppression of bone turnover had already existed in the femur with incomplete AFF. Compared to healthy premenopausal women, bone turnover is similarly suppressed in patients with either type of AFF.
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Affiliation(s)
- Shijing Qiu
- Bone and Mineral Research Laboratory, Henry Ford Hospital, Detroit, MI, USA.
| | - George W Divine
- Department of Public Health Sciences, Henry Ford Hospital, Detroit, MI, USA
| | - Saroj Palnitkar
- Bone and Mineral Research Laboratory, Henry Ford Hospital, Detroit, MI, USA
| | - Pooja Kulkarni
- Bone and Mineral Research Laboratory, Henry Ford Hospital, Detroit, MI, USA
| | - Trent S Guthrie
- Department of Orthopedic Surgery, Henry Ford Hospital, Detroit, MI, USA
| | - Mahalakshmi Honasoge
- Division of Endocrinology, Diabetes, and Bone and Mineral Disorders, Henry Ford Hospital, Detroit, MI, USA
| | - Sudhaker D Rao
- Bone and Mineral Research Laboratory, Henry Ford Hospital, Detroit, MI, USA
- Division of Endocrinology, Diabetes, and Bone and Mineral Disorders, Henry Ford Hospital, Detroit, MI, USA
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11
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McKenna MJ, McKiernan FE, McGowan B, Silke C, Bennett K, van der Kamp S, Ward P, Hurson C, Heffernan E. Identifying Incomplete Atypical Femoral Fractures With Single-Energy Absorptiometry: Declining Prevalence. J Endocr Soc 2017; 1:211-220. [PMID: 29264478 PMCID: PMC5686782 DOI: 10.1210/js.2016-1118] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Accepted: 02/08/2017] [Indexed: 12/13/2022] Open
Abstract
Background: Atypical femur fractures (AFFs) are associated with long-term bisphosphonate (BP) therapy. Early identification of AFF prior to their completion provides an opportunity to intervene, potentially reducing morbidity associated with these fractures. Single-energy X-ray absorptiometry (SE) is an imaging method recently shown to detect incomplete AFF (iAFF) prior to fracture completion. Methods: Between May 2013 and September 2014, we assessed 173 patients who had been prescribed BP therapy for >5 years for iAFF using SE at their presentation for routine bone mineral density testing. We compared these findings with those of our previously published prospective study (n = 257) in which the femur was imaged for iAFF using dual-energy X-ray absorptiometry. In addition, we estimated the yearly prevalence of complete AFF among patients with subtrochanteric fracture at our institution from 2006 to 2014, and we evaluated prescribing trends for BP in Ireland from 2009 to 2014. Results: No patients had iAFF using SE femur compared with a prevalence of 2.7% in the earlier study. Between 2006 and 2014, we observed a rise and decline in AFFs at our hospital and a similar national trend in BP prescribing. Conclusions: AFFs appear to be decreasing. New customized scan modes of dual-energy X-ray absorptiometry systems, which visualize the entire femur at high image quality and take measurements, have the potential to identify iAFF prior to fracture completion and to ascertain those at highest risk of AFF.
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Affiliation(s)
- Malachi J McKenna
- DXA Unit.,UCD School of Medicine, University College Dublin, Dublin, D04V1W8 Ireland
| | | | - Bernie McGowan
- The North Western Rheumatology Unit, Our Lady's Hospital, Manorhamilton, Co Leitrim, F91X012 Ireland; and
| | - Carmel Silke
- The North Western Rheumatology Unit, Our Lady's Hospital, Manorhamilton, Co Leitrim, F91X012 Ireland; and
| | - Kathleen Bennett
- Division of Population and Health Sciences, Royal College of Surgeons in Ireland, Dublin, D02YN77 Ireland
| | | | - Paul Ward
- Department of Orthopaedic Surgery, and
| | - Conor Hurson
- Department of Orthopaedic Surgery, and.,UCD School of Medicine, University College Dublin, Dublin, D04V1W8 Ireland
| | - Eric Heffernan
- Department of Diagnostic Imaging, St. Vincent's University Hospital, Dublin, D04T6F4 Ireland.,UCD School of Medicine, University College Dublin, Dublin, D04V1W8 Ireland
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Szolomayer LK, Ibe IK, Lindskog DM. Bilateral atypical femur fractures without bisphosphonate exposure. Skeletal Radiol 2017; 46:241-247. [PMID: 27900455 DOI: 10.1007/s00256-016-2526-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 10/24/2016] [Accepted: 10/27/2016] [Indexed: 02/02/2023]
Abstract
Atypical femur fractures have common radiographic features that set them apart from more typical higher-energy subtrochanteric femur fractures. They are noncomminuted, transverse fractures with medial spiking of the femoral cortex and increased lateral cortical thickness. These fractures have been associated in the literature with the use of bisphosphonate medications. This case describes bilateral atypical femur fractures in a patient with a medical history devoid of bisphosphonate use. We present his history, co-morbidities, and subsequent treatment. From this case, we call attention to bisphosphonate use as not the only cause of subtrochanteric femur fractures with atypical features and highlight that some patients may sustain these injuries even bilaterally without use of the medications. In addition, it is important to identify this fracture type and obtain imaging of the contralateral femur to facilitate prophylactic treatment if needed.
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Affiliation(s)
- Lauren K Szolomayer
- Department of Orthopaedics and Rehabilitation, Yale School of Medicine, 800 Howard Avenue, Suite 1st Floor, New Haven, CT, 06510, USA.
| | - Izuchukwu K Ibe
- Department of Orthopaedics and Rehabilitation, Yale School of Medicine, 800 Howard Avenue, Suite 1st Floor, New Haven, CT, 06510, USA
| | - Dieter M Lindskog
- Department of Orthopaedics and Rehabilitation, Yale School of Medicine, 800 Howard Avenue, Suite 1st Floor, New Haven, CT, 06510, USA
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