Atypical femoral fractures: epidemiology, etiology, and patient management

Atypical Femur Fractures-An Analysis of 69 Patients from 15 Years

Background/Objectives: Bisphosphonates are effective in preventing osteoporotic fractures. However, the risk of atypical femur fractures (AFFs) increases with long-term bisphosphonate use. There are few existing publications on the analysis of clinical outcomes of atypical femur fracture cases in Chinese patients. Our objective was to review the clinical outcomes of AFF cases managed in a tertiary center in Hong Kong, China. Methods: Cases of AFF managed in the Prince of Wales Hospital from 2010 to 2024 were included. Data on demographics, type and duration of bisphosphonate use prior to AFF, fixation method, and mobility 1 year post-operation were retrospectively retrieved. One-way ANOVA was used to compare the duration of use prior to the development of AFF between different types of bisphosphonates. Results: Sixty-nine cases of AFF were included, with a mean age of 73.8 ± 9.7 years. A total of 95.6% of patients had a history of bisphosphonate use, with a mean duration of usage of 6.8 ± 5.6 years prior to the occurrence of AFF. The duration of bisphosphonate use prior to the development of AFF was comparable between alendronate, ibandronate, and a history of using more than one type of anti-resorptive agent. A non-union rate of 5.8% was observed in the current cohort, with 48.2% returning to pre-morbid mobility 1 year post-operation. Conclusions: AFF is more commonly seen in female patients with a history of bisphosphonate use. Considering the high success rate demonstrated in the current cohort, treating AFF with closed reduction followed by fixation with a long cephalomedullary device in dynamic locking together with immediate full-weight-bearing rehabilitation post-operation may be effective.

Atypical Tibial Fracture Following Chronic Bisphosphonate Use: A Case Report and Review of the Literature

Atypical fractures are diagnosed when an otherwise normal force causes a fracture in a patient using bisphosphonates chronically. These occur most commonly in the subtrochanteric region of the femur. Yet, the literature on atypical tibial shaft fractures is scarce. We describe a case of a 60-year-old Hispanic female who presented with an atypical open tibial fracture with a seven-year history of bisphosphonate use, successfully managed with intramedullary nailing.

Atypical lumbar pedicle fractures. A case report and comparative review of the literature: Bisphosphonate-related? Possible matching with diagnostic criteria of atypical fractures of the femur

Introduction

Bisphosphonates are commonly used to prevent osteoporotic fractures. Many randomized controlled trials have proved the efficacy of bisphosphonates, showing their ability to increase bone mineral density and decrease the risk of hip and vertebral fractures. Atypical, bisphosphonate-related fractures concerning the femur have been widely described and a list of primary and secondary clinical and radiographic criteria are used in order to achieve diagnosis.

Research question

To identify clinical and radiographic findings for a possible association of vertebral fractures to prolonged bisphosphonate therapy.

Material and methods

In this paper we present a case of an atraumatic bilateral pedicle lumbar fracture, assuming the hypothesis of an insufficiency atypical fracture due to prolonged Alendronate therapy for osteoporosis. We highlight the various aspects for diagnosis, treatment and a review of the existing literature was carried out.

Discussion and conclusion

Atypical fractures in the spine are rarely reported in the literature. Pedicle anatomy is partially similar to a long bone, described as a strong bridge between the posterior arch and the vertebral body composed of a cortical bone and a cancellous core. Stress fractures are reported as a result of an underlying bone disease, trauma, post-surgery and stress fractures. In our opinion, the criteria described for atypical femoral fractures are a useful tool to also classify these rare pedicle lesions as insufficiency, bisphosphonate-correlated fractures.

Geriatric trauma: there is more to it than just the implant!

Geriatric trauma continues to rise, corresponding with the continuing growth of the older population. These fractures continue to expand, demonstrated by the incidence of hip fractures having grown to 1.5 million adults worldwide per year. This patient population and their associated fracture patterns present unique challenges to the surgeon, as well as having a profound economic impact on the health care system. Pharmacologic treatment has focused on prevention, with aging adults having impaired fracture healing in addition to diminished bone mineral density. Intraoperatively, novel ideas to assess fracture reduction to facilitate decreased fracture collapse have recently been explored. Postoperatively, pharmacologic avenues have focused on future fracture prevention, while shared care models between geriatrics and orthopaedics have shown promise regarding decreasing mortality and length of stay. As geriatric trauma continues to grow, it is imperative that we look to optimize all phases of care, from preoperative to postoperative.

Atypical Tibial Fracture Treated with Osteosynthesis Associated with Total Knee Arthroplasty: Case Report

Bisphosphonates are widely used in the treatment of osteoporosis but predispose the patient to the appearance of atypical fractures. The femoral subtrochanteric region is usually affected, but other bones can be as well. Atypical tibia fractures in patients with severe gonarthrosis is a therapeutic challenge. The present work reports the case of an elderly patient with advanced gonarthrosis who presented atypical tibial fracture. The patient made prolonged use of bisphosphonates for osteoporosis, presenting with pain and functional limitation resulting from gonarthrosis, which progressed to sudden pain in the right tibial metaphysis, preventing ambulation. The radiographs showed bilateral severe arthrosis; marked varism; tibial and femoral medial erosion; and fracture in the proximal third of the right tibial diaphysis. The fracture and arthrosis on the right side were treated by osteosynthesis with blocked plaque and total knee arthroplasty with posterior stabilization and fixed base. After physical rehabilitation, significant improvement of pain and function was reported, independent gait was reacquired and a range of motion of 0 to 100° was reached. After one year, the radiographs showed fracture consolidation and satisfactory alignment of the lower limbs' axes. The coexistence of severe arthrosis and atypical fracture made treatment difficult. However, the result was satisfactory and the approach with simultaneous osteosynthesis and arthroplasty proved to be adequate.

The role of the fracture liaison service in the prevention of atypical femoral fractures

Osteoporosis and fragility fractures (FFs) are considered critical health problems by the World Health Organization (WHO) because of high morbidity, mortality, and healthcare costs. The occurrence of a FF raises the risk of a subsequent fracture (refracture). The hip is the most common site of fragility refracture, and its onset is associated with a further increase in patient's morbidity, mortality, and socioeconomic burden. Therefore, the prevention of refracture is essential. In this context, fracture liaison service (FLS) demonstrated to be able to reduce FF risk and also improve patients' adherence to anti-osteoporotic treatments, particularly for bisphosphonates (BPs). However, long-term and high adherence to BPs may lead to atypical femoral fractures (AFFs). These latter are tensile side stress fractures of the femur, with high rates of complications, including delayed and non-healing. An effective FLS should be able to prevent both FF and AFF. A comprehensive and interdisciplinary approach, through the involvement and education of a dedicated team of healthcare professionals (i.e. orthopedic, geriatrician, primary care physician, rehabilitation team, and bone nurse) for evaluating both FF and AFF risks might be useful to improve the standard of care.

Atypical Femoral Fracture in Hypophosphatasia: A Systematic Review

Objective

To summarize the characteristics of all reported patients with hypophosphatasia (HPP) who sustained atypical femoral fracture (AFF) and identify all available evidence to quantify the rate of coexistence between HPP and AFF.

Methods

Potentially eligible articles were identified from the MEDLINE and EMBASE databases from its inception to September 2022, using a search strategy consisting of terms related to "Hypophosphatasia" and "Atypical femoral fracture." Eligible articles must report one of the following information: (1) individual data of patients diagnosed with HPP and AFF, (2) prevalence of HPP among patients with AFF, or (3) prevalence of AFF among patients of HPP. Characteristics of patients reported in each study were extracted.

Results

A total of 148 articles were identified. After the systematic review, 24 articles met the eligibility criteria. A total of 28 patients with AFF and HPP were identified. The mean ± SD age of the reported patients was 53.8 ± 12.5 years, and 22 patients (78.6%) were female. Nine patients (32.1%) received antiresorptive medication (bisphosphonate and/or denosumab), and two patients (7.1%) received teriparatide prior to the development of AFF. Seven (25.0%) and eighteen (64.3%) patients sustained unilateral and bilateral AFF, respectively (laterality not reported in three cases). Thirteen patients (46.4%) had a history of fractures at other sites. Four (14.3%) and seven (25.0%) patients received asfotase alfa and teriparatide after sustaining AFF. Two studies reported the prevalence of AFF among patients with HPP of approximately 10%. One study reported one HPP patient in a cohort of 72 patients with AFF.

Conclusions

Based on the limited evidence, AFF occurred in up to 10% of patients with HPP. Based on the 28 case reports, about two-thirds did not receive antiresorptive treatment, suggesting that the HPP itself could potentially be a risk factor for AFF.

Advancement in the Treatment of Osteoporosis and the Effects on Bone Healing

Osteoporosis (OP) is a major global health concern, with aging being one of the most important risk factors. Osteoarthritis (OA) is also an age-related disorder. Patients with OP and/or OA may be treated surgically for fractures or when their quality of life is impaired. Poor bone quality due to OP can seriously complicate the stability of a bone fixation construct and/or surgical fracture treatment. This review summarizes the current knowledge on the pathophysiology of normal and osteoporotic bone healing, the effect of a bone fracture on bone turnover markers, the diagnosis of a low bone mineral density (BMD) before surgical intervention, and the effect of available anti-osteoporosis treatment. Interventions that improve bone health may enhance the probability of favorable surgical outcomes. Fracture healing and the treatment of atypical femoral fractures are also discussed.

Plate osteosynthesis for atypical femoral fractures in patients with severely bowed femurs: comparing short versus long segment fixation - a case series

BACKGROUND

Intramedullary nail fixation is currently the modality of choice in surgical treatment for atypical femoral fractures (AFF). Its uses are limited, however, in severely bowed femurs, narrow medullary canals, or in the presence of thick endosteal callus at the apex of the femoral curve. In these cases, extramedullary plate osteosynthesis is preferred. The consideration when adopting plate osteosynthesis is whether a short or long segment fixation is superior. We hypothesize that a long segment fixation has the potential advantage of protecting the entire length of the femur from future fractures in the adynamic bone. In this series, we present two cases from our institution, with the aims of discussing the benefits and limitations of short versus long segment plate fixation in AFF.

CASE SUMMARY

We report two uncommon cases of bisphosphonate-related AFF in two Asian patients with severe femoral curvature, who were treated with extramedullary plate osteosynthesis at our institution. One patient underwent fixation with a short segment plate osteosynthesis, and the other received a long plate osteosynthesis spanning the proximal to distal femur in an attempt to protect the bone from future fractures. Both patients showed a favourable and uncomplicated course post-surgery, with early return to ambulation and radiographic bone union at follow up.

CONCLUSION

We expect to see an increase in the number of patients with AFF and bowed femurs, especially with the increased usage of bisphosphonates given an ageing Asian population. Surgical treatment with short and long plate osteosynthesis are options with their own advantages and limitations. With the advent of new anatomical plate options, long segment fixation has become more accessible and may be considered in this patient group as it has the potential advantage of protecting the adynamic femur from future fractures. Further studies should be targeted to determine which method of treatment is superior in this particular group of patients.

Pharmacological interventions versus placebo, no treatment or usual care for osteoporosis in people with chronic kidney disease stages 3-5D

BACKGROUND

Chronic kidney disease (CKD) is an independent risk factor for osteoporosis and is more prevalent among people with CKD than among people who do not have CKD. Although several drugs have been used to effectively treat osteoporosis in the general population, it is unclear whether they are also effective and safe for people with CKD, who have altered systemic mineral and bone metabolism.

OBJECTIVES

To assess the efficacy and safety of pharmacological interventions for osteoporosis in patients with CKD stages 3-5, and those undergoing dialysis (5D).

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 25 January 2021 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

Randomised controlled trials comparing any anti-osteoporotic drugs with a placebo, no treatment or usual care in patients with osteoporosis and CKD stages 3 to 5D were included.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies, assessed their quality using the risk of bias tool, and extracted data. The main outcomes were the incidence of fracture at any sites; mean change in the bone mineral density (BMD; measured using dual-energy radiographic absorptiometry (DXA)) of the femoral neck, total hip, lumbar spine, and distal radius; death from all causes; incidence of adverse events; and quality of life (QoL). Summary estimates of effect were obtained using a random-effects model, and results were expressed as risk ratios (RR) and their 95% confidence intervals (CI) for dichotomous outcomes, and mean difference (MD) for continuous outcomes. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

Seven studies involving 9164 randomised participants with osteoporosis and CKD stages 3 to 5D met the inclusion criteria; all participants were postmenopausal women. Five studies included patients with CKD stages 3-4, and two studies included patients with CKD stages 5 or 5D. Five pharmacological interventions were identified (abaloparatide, alendronate, denosumab, raloxifene, and teriparatide). All studies were judged to be at an overall high risk of bias. Among patients with CKD stages 3-4, anti-osteoporotic drugs may reduce the risk of vertebral fracture (RR 0.52, 95% CI 0.39 to 0.69; low certainty evidence). Anti-osteoporotic drugs probably makes little or no difference to the risk of clinical fracture (RR 0.91, 95% CI 0.79 to 1.05; moderate certainty evidence) and adverse events (RR 0.99, 95% CI 0.98 to 1.00; moderate certainty evidence). We were unable to incorporate studies into the meta-analyses for BMD at the femoral neck, lumbar spine and total hip as they only reported the percentage change in the BMD in the intervention group. Among patients with severe CKD stages 5 or 5D, it is uncertain whether anti-osteoporotic drug reduces the risk of clinical fracture (RR 0.33, 95% CI 0.01 to 7.87; very low certainty evidence). It is uncertain whether anti-osteoporotic drug improves the BMD at the femoral neck because the certainty of this evidence is very low (MD 0.01, 95% CI 0.00 to 0.02). Anti-osteoporotic drug may slightly improve the BMD at the lumbar spine (MD 0.03, 95% CI 0.03 to 0.04, low certainty evidence). No adverse events were reported in the included studies. It is uncertain whether anti-osteoporotic drug reduces the risk of death (RR 1.00, 95% CI 0.22 to 4.56; very low certainty evidence).

AUTHORS' CONCLUSIONS

Among patients with CKD stages 3-4, anti-osteoporotic drugs may reduce the risk of vertebral fracture in low certainty evidence. Anti-osteoporotic drugs make little or no difference to the risk of clinical fracture and adverse events in moderate certainty evidence. Among patients with CKD stages 5 and 5D, it is uncertain whether anti-osteoporotic drug reduces the risk of clinical fracture and death because the certainty of this evidence is very low. Anti-osteoporotic drug may slightly improve the BMD at the lumbar spine in low certainty evidence. It is uncertain whether anti-osteoporotic drug improves the BMD at the femoral neck because the certainty of this evidence is very low. Larger studies including men, paediatric patients or individuals with unstable CKD-mineral and bone disorder are required to assess the effect of each anti-osteoporotic drug at each stage of CKD.

Bisphosphonate-related atypical femoral fractures: A novel strategy to improve patient outcomes

Background:

Atypical femoral fracture (AFF) is a serious adverse event associated with bisphosphonate therapy and prone to complications and delayed union. We propose a technique and management strategy to maximise bone healing and outcomes.

Methods:

We report on a cohort of patients with AFF using our novel technique of preparing the intramedullary canal and rigid fixation with cephalomedullary nailing. Patients were admitted under a multidisciplinary team with rehabilitation goals of early mobilisation and teriparatide initiation. Clinical and radiographic data were retrospectively reviewed.

Results:

Twenty-eight AFFs were treated with a mean follow-up of 58.5 weeks and a mean age of 75.2 years old. All cases achieved radiological union by a mean of 6 months and post-operative thigh pain experienced up to 8.7 weeks. No cases underwent revision or experienced intraoperative complication.

Conclusion:

Our surgical technique and multidisciplinary management are reproducible with excellent results in patients with this rare yet challenging injury.

Imaging Features and Management of Stress, Atypical, and Pathologic Fractures

Traumatic and atraumatic fractures are entities with distinct but often overlapping clinical manifestations, imaging findings, and management protocols. This article is a review of terminology, etiology, and key imaging features that affect management of atraumatic fractures including stress fractures, atypical femoral fractures, and pathologic fractures. The terminology of atraumatic fractures is reviewed, with an emphasis on the distinctions and similarities of stress, atypical, and pathologic fractures. The basic biomechanics of normal bone is described, with an emphasis on the bone remodeling pathway. This framework is used to better convey the shared etiologies, key differences, and important imaging findings of these types of fractures. Next, the characteristic imaging findings of this diverse family of fractures is discussed. For each type of fracture, the most clinically relevant imaging features that guide management by the multidisciplinary treatment team, including orthopedic surgeons, are reviewed. In addition, imaging features are reviewed to help discriminate stress fractures from pathologic fractures in patients with challenging cases. Finally, imaging criteria to risk stratify an impending pathologic fracture at the site of an osseous neoplasm are discussed. Special attention is paid to fractures occurring in the proximal femur because the osseous macrostructure and mix of trabecular and cortical bone of the proximal femur can function as a convenient framework to understanding atraumatic fractures throughout the skeleton. Atraumatic fractures elsewhere in the body also are used to illustrate key imaging features and treatment concepts. ^©RSNA, 2018.

Pharmacological interventions for osteoporosis in people with chronic kidney disease stages 3‐5D

This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:

This review aims to assess the effects of pharmacological interventions for osteoporosis in patients with CKD stages 3‐5D.

Spontaneous Insufficiency Fractures

Spontaneous insufficiency fractures are caused by normal or physiological stress on weakened bone. The leading cause of insufficiency fractures is osteoporosis which has a propensity to affect older patients. Other causes or associated factors are disorders which affect bone metabolism, collagen formation, bone remodelling and medications such as bisphosphonates and glucocorticoids. Pathological fractures and abuse are important causes of unexplained fractures which warrant careful consideration. Spontaneous fractures of the long bones affect on average 1% of nursing home residents per year and tend to occur in patients who are bed-bound with joint contractures. Preventative measures for spontaneous insufficiency fractures include optimising nutrition to include an adequate intake of protein, calcium and vitamin D, maintaining mobility and preventing long periods of bed-rest and treatment of underlying pre-disposing conditions.

Surgical Management of Atypical Femur Fractures Associated With Bisphosphonate Therapy

Atypical femur fractures associated with long-term bisphosphonate use can be challenging injuries to manage. Not only do they have a prolonged healing time and increased rate of nonunion as compared to typical femur fractures, intraoperative complications are not infrequent and can be catastrophic. Given the pathologic nature of these fractures, a multidisciplinary approach to the patient's care is necessary. Treatment begins with medical optimization and careful surgical planning. Radiographic characteristics of the fracture and femoral osteology dictate reduction strategy, adjunctive surgical techniques, and implant choice. Intraoperative complications including malreduction, iatrogenic fracture, and fracture propagation can be avoided with thoughtful planning. The purpose of this article is to discuss the technical aspects of surgical management of atypical femur fractures. We also discuss management of intraoperative complications and treatment failure. Finally, we provide an update on recommendations for postoperative medical treatment and management of the contralateral femur.

Endoprosthetic Reconstruction for a Displaced Atypical Femoral Fracture in a Cancer Patient with Poor Prognosis

Zoledronate or denosumab treatment is beneficial for cancer patients with bone metastasis. However, each agent may trigger atypical femoral fractures. Incomplete atypical femoral fractures can be successfully treated with prophylactic intramedullary nailing. On the other hand, intramedullary nailing for displaced atypical femoral fractures occasionally causes problems with regard to bone healing, resulting in long-term treatment. In cancer patients with poor prognosis who experience atypical femoral fractures, improvement in activities of daily living should be the priority. Thus, we performed endoprosthetic reconstruction for a displaced atypical femoral fracture in a breast cancer patient with poor prognosis to enable walking in the early stage after the operation. Two weeks after the operation, she could successfully walk. The postoperative Musculoskeletal Tumor Society score was 47%, and it had improved to almost the preoperative level before injury (50%). In conclusion, endoprosthetic reconstruction for displaced atypical femoral fractures may be a first-line treatment approach to acquire early postoperative walking ability for improving activities of daily living in cancer patients with poor prognosis.

The Influence of Cortical Porosity on the Strength of Bone During Growth and Advancing Age

PURPOSE OF REVIEW

Bone densitometry provides a two-dimensional projected areal apparent bone mineral density that fails to capture the heterogeneity of bone's material composition and macro-, micro-, and nano-structures critical to its material and structural strength. Assessment of the structural basis of bone fragility has focused largely on trabecular bone based on the common occurrence of fragility fractures at sites with substantial amounts of trabecular bone. This review focuses on the contribution of cortical bone to bone fragility throughout life.

RECENT FINDINGS

Accurately differentiating cortical and trabecular bone loss has important implications in quantifying bone fragility as these compartments have differing effects on bone strength. Recent advances in imaging methodology have improved distinction of these two compartments by (i) recognition of a cortico-trabecular transitional zone and (ii) quantifying bone microstructure in a region of interest that is a percentage of bone length rather than a fixed point. Additionally, non-invasive three-dimensional imaging methods allow more accurate quantification of changes in the cortical, trabecular, and cortico-trabecular compartments during growth, aging, disease, and treatment. Over 75% of the skeleton is assembled as cortical bone. Of all fragility fractures, ~ 80% are appendicular and involve regions rich in cortical bone and ~ 70% of all age-related appendicular bone loss is cortical and is mainly due to unbalanced intracortical remodeling which increases cortical porosity. The failure to achieve the optimal peak bone microstructure during growth due to disease and the deterioration in cortical and trabecular bone produced by bone loss compromise bone strength. The loss of strength produced by microstructural deterioration is disproportionate to the bone loss producing this deterioration. The reason for this is that the loss of strength increases as a 7th power function of the rise in cortical porosity and a 3rd power function of the fall in trabecular density (Schaffler and Burr in J Biomech. 21(1):13-6, 1988), hence the need to quantify bone microstructure.

A proposal for an atypical femur fracture treatment and prevention clinical practice guideline

The prevention as well as the treatment of atypical femur fractures (AFFs) remains controversial but there have been many clinical recommendations suggested. We have summarized these recommendations as well as expanded upon them in this paper.

INTRODUCTION

The purpose of the paper was to develop a clinical practice guideline that both treats AFF and decreases the risk of AFF in patients requiring antiresorptive medications. Examples of these medications include bisphosphonates and denosumab for the treatment of osteoporosis.

METHODS

A literature review looking for recommendations on AFF identification, management, and prevention was done. We also performed an updated review of clinical guidelines on AFF prevention and treatment that were developed for the Kaiser Permanente osteoporosis/fracture prevention team.

RESULTS

Concise clinical practice guidelines are presented that can be applied in treatment of AFF as well as help reduce the risk of developing an AFF in patients requiring antiresorptive medications. These guidelines are based on using both typical fracture and AFF risk assessment to determine duration of antiresorptive of 3 to 5 years before consideration if a drug holiday is needed. Specific groups such as younger Asian women should be reassessed at 3 years with DXA and FRAX to see if a drug holiday is needed whereas patients at higher risk for typical fractures may be reassessed at 5 years of treatment. The DXA rescreening can now be accessed if focal or generalized lateral cortex changes are present that may indicate incomplete AFFs are present. If an incomplete AFF is discovered either by DXA or by other imaging studies, it is imperative to stop antiresorptive medications and to take additional measures to lower the risk of progression to a complete AFF. If complete AFF does occur, then antiresorptive medications should be stopped and additional measures should be taken to decrease the risk of developing an AFF on the contralateral femur.

CONCLUSIONS

Clinical practice guidelines for the treatment and prevention of AFF will benefit clinicians who are frequently faced with having to make clinical decisions in patients requiring antiresorptive medications.

Influence of geometry on proximal femoral shaft strains: Implications for atypical femoral fracture

INTRODUCTION

Atypical femoral fractures (AFF) are characterized as low-energy fractures of the femoral shaft or subtrochanteric region. Femoral geometry is known to play a role in AFF risk; it is hypothesized that high-risk geometries are associated with elevated femoral shaft strain. However, it is not well known which geometric parameters have the greatest effect on strain, or whether interaction between parameters is significant. The purpose of this study was to thoroughly quantify the relationship between femoral geometry and diaphyseal strain, using patient specific finite element (FE) modelling in concert with parametric mesh morphing.

METHODS

Ten FE models were generated from computed tomography (CT) images of cadaveric femora. Heterogeneous material properties were assigned based on average CT intensities at element locations and models were subject to loads and boundary conditions representing the stance phase of gait. Mesh morphing was used to manipulate 8 geometric parameters: neck shaft angle (NSA), neck version angle (NV), neck length (NL), femoral length (FL), lateral bowing angle (L.Bow), anterior bowing angle (A.Bow), shaft diameter (S.Dia), and cortical bone thickness (C·Th). A 2-Level full factorial analysis was used to explore the effect of different combinations of physiologically realistic minimum and maximum values for each parameter. Statistical analysis (Generalized Estimating Equations) was used to assess main effects and first order interactions of each parameter.

RESULTS

Six independent parameters and seven interaction terms had statistically significant (p<0.05) effects on peak strain and strained volume. For both measures, the greatest changes were caused by S.Dia, L.Bow, and A.Bow, and/or first order interactions involving two of these variables.

CONCLUSIONS

As hypothesized, a large number of geometric measures (six) and first order interactions (seven) are associated with changes in femoral shaft strain. These measures can be evaluated radiographically, which may have important implications for future studies investigating AFF risk in clinical populations.

Subtrochanteric femoral stress fracture with features of atypical femoral fracture in patient with Paget's disease: a case report

Atypical femoral fracture (AFF) has been widely issued since the American Society for Bone and Mineral Research (ASBMR) taskforce stated a possible association with long-term use of bisphosphonate in 2010. ASBMR taskforce recommended to include Paget's disease as one of variables to investigate the AFF in 2010. On the other hand, the ASBMR taskforce in 2014 excluded Paget's disease in the definition of AFF. Still, any rationale has been barely documented about this change. We described the rationale by reporting an 85-year-old man who had a subtrochanteric fracture with features of atypical femoral fracture which turned out to be Paget's disease of bone in the pathology.

Proceedings of the 2017 Santa Fe Bone Symposium: Insights and Emerging Concepts in the Management of Osteoporosis

The 18th Annual Santa Fe Bone Symposium was held on August 4-5, 2017, in Santa Fe, New Mexico, USA. The symposium convenes health-care providers and clinical researchers to present and discuss clinical applications of recent advances in research of skeletal diseases. The program includes lectures, oral presentations by endocrinology fellows, case-based panel discussions, and breakout sessions on topics of interest, with emphasis on participation and interaction of all participants. Topics included the evaluation and treatment of adult survivors with pediatric bone diseases, risk assessment and management of atypical femur fractures, nonpharmacologic strategies in the care of osteoporosis, and skeletal effects of parathyroid hormone with opportunities for therapeutic intervention. Management of skeletal complications of rheumatic diseases was discussed. Insights into sequential and combined use of antiresorptive agents were presented. Individualization of patient treatment decisions when clinical practice guidelines may not be applicable was covered. Challenges and opportunities with osteoporosis drug development were discussed. There was an update on progress of Bone Health TeleECHO (Bone Health Extension for Community Healthcare Outcomes), a teleconferencing strategy for sharing knowledge and expanding capacity to deliver best-practice skeletal health care.

Teriparatide treatment in an adult patient with hypophosphatasia exposed to bisphosphonate and revealed by bilateral atypical fractures

Atypical femoral fractures are defined as atraumatic fractures located in the subtrochanteric region or femoral shaft. They have been mainly reported in patients taking bisphosphonates. We report the case of a 67-year-old female with osteoporosis treated by alendronate during ten years. Radiographies showed atypical femoral fractures. Serum levels of total and bone-specific alkaline phosphatase were low. In order to accelerate bone healing, teriparatide was introduced. After one year of teriparatide treatment, pain and functional difficulty have decreased, and alkaline phosphatase levels were normalized. In view of this history of recurrent fractures, of atypical femoral fractures, of early spontaneous loss of teeth, and of low serum total and bone-specific alkaline phosphatase levels, the diagnosis of hypophosphatasia has been considered and confirmed by genetic research. Other conditions than exposure to anti-resorptive therapies may promote atypical femoral fractures, such as in conditions associated with abnormal bone structures, as hypophosphatasia, a rare inherited bone metabolism disorder. A few case reports have reported adult hypophosphatasia treated by teriparatide with a good efficacy on bone pain and consolidation but with mixed results on biological markers. Teriparatide may be therefore a treatment option in adult hypophosphatasia. ALP levels should be carefully checked among osteoporotic patients and specially before introducing a bone resorption inhibitor. Low alkaline phosphatase levels have to be taken into account and an evocative history of hypophosphatasia has to be sought because this condition may expose patients to develop atypical femoral fractures during bisphosphonate treatment.

Osteoporosis: a discussion on the past 5 years

PURPOSE OF THE REVIEW

The purposes of this study are to examine the literature within the past 5 years regarding osteoporosis and offer a discussion on new topics and controversies.

RECENT FINDINGS

Patient compliance with therapy remains an issue. The effectiveness of Vitamin D and calcium are being called into question Atypical femur fractures have been associated with bisphosphonate and denosumab use. Treatment is both surgical and pharmaceutical. A multidisciplinary approach to osteoporotic fractures is important and having some form of fracture liaison service (FLS) improves the efficacy of osteoporotic care and decreases secondary fractures. Screening for osteoporosis remains low. Ultrasound may be cost-effective for diagnosis. Understanding of osteoporosis has come a long way in the medical community, but the translation to the lay community has lagged behind. Patients often take a laissez-faire attitude toward osteoporosis that can affect compliance. Information read by patients often focuses on complications, such as atypical femur fractures and myocardial infarctions. It is essential for providers to be able to discuss these issues with patients. Newer medications and more cost-effective diagnostic tests exist, but availability may be limited. FLS are effective, but the most cost-effective model for therapy still eludes us. Areas for further investigation include FLS models, the effectiveness of vitamin supplementation, and more ubiquitous and cost-effective diagnostic tools.

Retrospective Review of Atypical Femoral Fracture in Metastatic Bone Disease Patients Receiving Denosumab Therapy

BACKGROUND

Denosumab therapy is used to reduce skeletal-related events in metastatic bone disease (MBD). There have been reports of atypical femoral fracture (AFF) in osteoporotic patients treated with denosumab but none in the context of higher dose and more frequent denosumab therapy for MBD. The goal of this study was to assess the incidence of AFF in MBD.

PATIENTS AND METHODS

We conducted a retrospective review of 253 patients who received a minimum of 12 doses of denosumab at 120 mg each for MBD. To identify patients with asymptomatic atypical stress reactions in the lateral subtrochanteric femur (which precede fractures), we reviewed the skeletal images of 66 patients who had received at least 21 doses of denosumab for AFF features.

RESULTS

These patients received a median of 17 doses, with a median treatment duration of 23 months. There was 1 case of undiagnosed clinical AFF detected after chart review and 2 cases of subclinical atypical femoral stress reaction observed on imaging review after 23 doses of denosumab over 33 months, 28 doses over 27 months, and 21 doses over 21 months, respectively. Scout computed tomography films showed diffuse cortical thickening of diaphysis with localized periosteal reaction of lateral femoral cortex. Bone scan and magnetic resonance imaging scan of 2 patients with stress reactions confirmed the diagnosis.

CONCLUSION

The incidence of clinical AFF in this context is 0.4% (1/253; 95% confidence interval [CI] 0.1%-2.2%), and the incidence of atypical femoral stress reaction based on imaging review is 4.5% (3/66; 95% CI 1.6%-12.5%). Clinicians should be aware of the clinical prodrome (which may or may not be present) and antecedent imaging changes associated with AFF. The Oncologist 2017;22:438-444Implications for Practice: Among patients with metastatic bone disease treated with denosumab, cases of clinical and subclinical atypical femoral fracture (AFF) are rare. The one detected case of clinical fracture went unrecognized despite prodromic symptoms. Clinicians should be aware of (a) the potential prodrome of anterior thigh/groin pain and (b) subclinical imaging changes in the lateral femur, both of which may precede clinical AFF.

Atypical Complete Femoral Fractures Associated with Bisphosphonate Use or Not Associated with Bisphosphonate Use: Is There a Difference?

The purpose of this study is to compare clinical characteristics and surgical outcome of atypical complete femoral fractures associated with bisphosphonates (BPs) use and those of fractures not associated with BPs use. Seventy-six consecutive patients (81 fractures) who had been operatively treated for a complete atypical femoral fracture were recruited. Of the 81 fractures, 73 occurred after BPs medication of at least 3 years (BP group) while 8 occurred without a history of BP medication (non-BP group). There were no differences in demographic data and fracture- and surgery-associated factors between the two groups. Of 76 patients (81 fractures), 54 (66.7%) fractures showed bony union within 6 months after the index surgery and 23 (28.4%) showed delayed union at a mean of 11.2 months (range, 8–18 months). The remaining 4 fractures were not healed, even 18 months after the index surgery. There was no difference in healing rate between the BP group and the non-BP group. There were strong correlations between the fracture height and the degree of bowing regardless of BPs medication. All fractures except 1 occurred at the diaphyseal region of the femur when not associated with BP medication.

Incidence of Atypical Femur Fractures in Cancer Patients: The MD Anderson Cancer Center Experience

Atypical femoral fractures (AFFs) are rare adverse events attributed to bisphosphonate (BP) use. Few cases of AFF in cancer have been described; the aim of this study is to identify the incidence and risk factors for AFF in a large cancer center. This retrospective study was conducted at the MD Anderson Cancer Center. The incidence rate of AFF among BP users was calculated from January 1, 2004 through December 31, 2013. The control group (n = 51) included 2 or 3 patients on BPs matched for age (≤1 year) and gender. Logistic regression analysis was used to assess the relationship between clinical characteristics and AFF. Twenty-three AFF cases were identified radiographically among 10,587 BP users, the total BP exposure was 53,789 months (4482 years), and the incidence of AFF in BP users was 0.05 cases per 100,000 person-years. Meanwhile, among 300,553 patients who did not receive BPs there were 2 cases of AFF as compared with the 23 cases noted above. The odds ratio (OR) of having AFF in BP users was 355.58 times higher (95% CI, 84.1 to 1501.4, p < 0.0001) than the risk in non-BP users. The OR of having AFF in alendronate users was 5.54 times greater (OR 5.54 [95% CI, 1.60 to 19.112, p = 0.007]) than the odds of having AFF among other BP users. Patients who were on zoledronic acid (ZOL) had smaller odds of developing AFF compared with other BP users in this matched case control sample. AFFs are rare, serious adverse events that occur in patients with cancer who receive BP therapy. Patients with cancer who receive BPs for prior osteoporosis therapy or for metastatic cancer are at higher risk of AFF. © 2016 American Society for Bone and Mineral Research.

Atypical femoral fractures and current management

With the rapid increase in patients receiving bisphosphonates (BPs) for treating osteoporosis, one of the clinical complications associated with its long-term use is atypical femoral fractures (AFFs). Although the absolute risk for AFFs is low and it was a consensus that AFFs were acceptable compared with the amount of osteoporotic fractures BPs have prevented, epidemiological studies have proved that BPs had a strong association with AFFs and possibly more people were going to suffer from this adverse effect with wide prescriptions of this drug. In addition, AFFs seemed to have impaired ability to heal. Thus, to understand the mechanism(s) behind AFFs is important and desirable for considering preventive measures. This article reviewed the clinical features of AFFs as well as potential underlining pathological characteristics, such as the decreased turnover rate caused by BPs that led to multiple-level alternations, e.g., changes not only at cellular and tissue levels, but also related to changes in bone micro- and macrostructure and organic/inorganic contents, leading to potentially compromised mechanical properties of cortical bone when exposed to prolonged BP therapy. Severely suppressed bone turnover may also be the underlying mechanism for impaired fracture healing in patients with AFFs. The rising concerns about the risk for AFFs in nonosteoporotic patients receiving high-dose BPs to treat cancers were also discussed. Detailed investigation will help develop potential targeted pharmacological treatments such as parathyroid hormone. In addition, potential innovative internal fixation implants were discussed with regard to dynamic and biological fixation for enhancing AFF repair.

Audit of Atypical Femoral Fractures and a Description of Some of Their Features

PURPOSE

Atypical femoral fractures (AFF) are recently described events related to osteoporosis and, potentially, a rare result of antiresorptive treatment.

METHODS

We set out to audit the diagnosis of AFF in an acute hospital. Charts and radiographs were reviewed retrospectively from patients diagnosed with subtrochanteric femoral fractures according to hospital discharge coding at Vancouver General Hospital (VGH), Canada, from January 2005 to March 2013.

RESULTS

A total of 3084 patients were discharged from the hospital with a diagnosis of hip fracture between 2005 and 2013. Of these, 204 were coded as having had subtrochanteric fractures; 178 of the patients thus coded had radiographic evidence of other fracture types-usually intertrochanteric fractures. Eleven patients did not have available radiographs. Of the remaining 193 patients whose radiographs were reviewed, 24 (12.4%) fulfilled the published criteria for AFF.

OUR OBSERVATIONS WERE

1) laterality: 13 of 24 AFF (54.2%) were right-sided; 2) there was only one incomplete AFF in this series: a completed fracture was an inclusion criterion, but 1 patient with an AFF had both that fracture and an incomplete fracture and further foci of periosteal or endosteal foci of new bone (PENB) involving the contralateral femur; 3) radiologists had only diagnosed AFF in only 1 of the 24 patients with characteristic radiographic signs of AFF; 4) all but 1 patient had a focus of periosteal and/or endosteal new bone (PENB) through which the fracture line invariably passed, and in the 1 exception the radiography was too poor to be sure of this but there was a symmetrical contralateral focus of PENB; 5) in 19 of 24 patients there was an adequate image of part of the contralateral femur and of these 12 (63%) had a contralateral focus of PENB situated ±2.5 cm from the index lesion site when measured from the upper aspect of the greater trochanter, and in another patient a prior fracture of the contralateral femur had been treated surgically and it was at a symmetrical contralateral location from the index fracture.; 6) in 3 of the 19 patients multiple foci of PENB were detected on the lateral aspect of the contralateral femur even though the examination was of limited extent; and 7) AFFs were associated with bisphosphonate medication in 75% of the patients studied.

CONCLUSIONS

Hospital discharge coding misclassified a great majority of femoral fractures as subtrochanteric. As an essential criteria for diagnosing AFF is their subtrochanteric location, this misclassification impaired our ability to retrospectively search for AFF patients. Radiologists tended not to report AFF when typical radiographic characteristics were present. Bilateral and multifocal disease is of interest in pointing to the diagnosis and in suggesting that the mechanism of injury in respect of these unusual fractures is more complex than simple low-energy trauma.

Atypical femur fractures in patients receiving bisphosphonate therapy: etiology and management

Osteoporosis is a growing problem that is projected to affect more than 50% of American adults by 2020. Bisphosphonate therapy is currently the primary mode of treating osteoporosis in this population. While bisphosphonate therapy has been successful in increasing bone mineral density, data has shown an increased risk of atypical femur fractures with prolonged therapy. Atypical femur fractures are characterized by low-energy or atraumatic injuries that occur in the subtrochanteric region. They originate on the medial cortex, travel transversely, and typically have little or no comminution. Conservative therapy is indicated for patients with incomplete fractures without prodromal symptoms. Patients with incomplete fractures and significant prodromal symptoms or visible fracture line on radiographs, those who have failed conservative management, and those with complete fractures should be treated with intramedullary nail fixation. Evaluation should involve imaging of the contralateral femur. Teriparatide therapy may be considered for patients without contraindications. While the incidence of these fractures is low, it is likely that these rates will increase with the aging population and increased prevalence of patients being treated with bisphosphonate therapy.

Bilateral Atypical Femoral Fracture in a Man on Long-Term Bisphosphonate and Glucocorticoid Therapy: A Case Report

CASE

We present here, to our knowledge, the first case of a male patient with a sequential bilateral atypical femoral fracture associated with long-term use of bisphosphonates to treat glucocorticoid-induced osteoporosis.

CONCLUSIONS

Given the known effectiveness of bisphosphonates, both their use and the potential complication of rare atypical femoral fractures have increased. These fractures are understood to occur when there is an alteration in the bone quality and its resistance to fatigue fracture in a subgroup of patients receiving bisphosphonates or denosumab.

Research perspectives: The 2013 AAOS/ORS research symposium on Bone Quality and Fracture Prevention

Bone fracture resistance is determined by the amount of bone present ("bone quantity") and by a number of other geometric and material factors grouped under the term "bone quality." In May 2013, a workshop was convened among a group of clinicians and basic science investigators to review the current state of the art in Bone Quality and Fracture Prevention and to make recommendations for future directions for research. The AAOS/ORS/OREF workshop was attended by 64 participants, including two representatives of the National Institutes of Arthritis and Musculoskeletal and Skin Diseases and 13 new investigators whose posters stimulated additional interest. A key outcome of the workshop was a set of recommendations regarding clinically relevant aspects of both bone quality and quantity that clinicians can use to inform decisions about patient care and management. The common theme of these recommendations was the need for more education of clinicians in areas of bone quality and for basic science studies to address specific topics of pathophysiology, diagnosis, prevention, and treatment of altered bone quality. In this report, the organizers with the assistance of the speakers and other attendees highlight the major findings of the meeting that justify the recommendations and needs for this field.

Atypical femur fractures

Atypical femur fractures were first reported in 2007 and are now recognized as a unique clinical entity. They occur along the shaft of the femur extending from the subtrochanteric region proximally to the distal femoral metaphysis. These fractures have an increased incidence in patients taking bisphosphonates for osteoporosis and develop as stress reactions in the lateral cortex of the femoral shaft. The fractures often have a distinct radiographic appearance with thickening or beaking of the lateral cortex. Treatment should be initiated immediately. There is a higher incidence of complications with atypical fractures. Early detection of these fractures can greatly reduce morbidity.

Atypical subtrochanteric and diaphyseal femoral fractures: second report of a task force of the American Society for Bone and Mineral Research

Bisphosphonates (BPs) and denosumab reduce the risk of spine and nonspine fractures. Atypical femur fractures (AFFs) located in the subtrochanteric region and diaphysis of the femur have been reported in patients taking BPs and in patients on denosumab, but they also occur in patients with no exposure to these drugs. In this report, we review studies on the epidemiology, pathogenesis, and medical management of AFFs, published since 2010. This newer evidence suggests that AFFs are stress or insufficiency fractures. The original case definition was revised to highlight radiographic features that distinguish AFFs from ordinary osteoporotic femoral diaphyseal fractures and to provide guidance on the importance of their transverse orientation. The requirement that fractures be noncomminuted was relaxed to include minimal comminution. The periosteal stress reaction at the fracture site was changed from a minor to a major feature. The association with specific diseases and drug exposures was removed from the minor features, because it was considered that these associations should be sought rather than be included in the case definition. Studies with radiographic review consistently report significant associations between AFFs and BP use, although the strength of associations and magnitude of effect vary. Although the relative risk of patients with AFFs taking BPs is high, the absolute risk of AFFs in patients on BPs is low, ranging from 3.2 to 50 cases per 100,000 person-years. However, long-term use may be associated with higher risk (∼100 per 100,000 person-years). BPs localize in areas that are developing stress fractures; suppression of targeted intracortical remodeling at the site of an AFF could impair the processes by which stress fractures normally heal. When BPs are stopped, risk of an AFF may decline. Lower limb geometry and Asian ethnicity may contribute to the risk of AFFs. There is inconsistent evidence that teriparatide may advance healing of AFFs.

Treatment of Pathological Bone Fractures in a Patient with McCune-Albright Syndrome

McCune-Albright syndrome is a rare genetic disorder with typical skeletal and endocrine manifestations. The disease course is complicated by recurrent fractures resulting from polyostotic fibrous dysplasia and the treatment is thus primarily directed at the reduction of the risk of fractures. However, due to the complex mechanism of the skeletal damage the standard antiporotic therapeutics are ineffective. We report here a case of a 31-year-old female, diagnosed with the McCune-Albright syndrome in early childhood. She was suffering from extensive bone involvement, complicated by recurrent fractures despite the treatment with bisphosphonates. In addition, the disease course was complicated by the impairment of several endocrine functions—precocious puberty, hyperestrogenism, and hyperthyroidism for which a total thyroidectomy was performed. During the operation, two enlarged parathyroid glands were removed. This resulted in severe hypocalcaemia in the postoperative period with a need for supplementation with very high calcium and vitamin D doses. After this episode, the patient has remained free of fractures. We discuss here the corrected thyroid function, the supplementation with unconventionally high doses of vitamin D and calcium, and the termination of bisphosphonates treatment as presumable factors contributing to the reduced fracture risk in this patient.