Management of atypical femoral fracture: a scoping review and comprehensive algorithm

Update on Atypical Femoral Fractures

➤ Atypical femoral fractures (AFFs) are stress fractures between the lesser trochanter and the metaphyseal flare that are most commonly related to prolonged (3 to 5 years) antiresorptive medication use.➤ An important finding is a visible transverse line in the lateral cortex, known as the "dreaded black line." Complete fractures are transverse and have minimal comminution.➤ Prodromal symptoms including hip, groin, thigh, and knee pain are present in more than one-half of cases and are usually misdiagnosed.➤ Nonoperative treatment for all patients with AFF includes withdrawal of bisphosphonates, assessment for secondary causes of osteoporosis, and optimization of vitamin D and calcium.➤ Incomplete fractures without a visible line can initially be treated nonoperatively with protected weight-bearing.➤ Intramedullary nailing is indicated for complete fractures and incomplete fractures with a visible fracture line. Delayed healing after fixation should be anticipated.➤ Treatment with parathyroid hormone (PTH) analogs (teriparatide and abaloparatide) after AFF prevents other fractures in high-risk patients, but the effect on healing of the fracture is unclear.

Atypical Periprosthetic Femoral Fracture Might be Considered a Distinct Subtype of Atypical Femoral Fracture: A Retrospective Study

OBJECTIVE

The exact relationship among atypical periprosthetic femoral fractures (APFFs), typical periprosthetic femoral fractures (PFFs), and atypical femur fractures (AFFs) remains unclear. This study aimed to investigate the prevalence of APFFs among PFFs and to identify the clinical characteristics, management, and prognosis that distinguish APFFs from typical PFFs and AFFs to further determine the relationship among these three fracture types.

METHODS

In this retrospective study, we reviewed the clinical data of 117 consecutive patients who had PFFs after hip arthroplasty between January 2012 and December 2022 and further classified them into an APFF group and a typical PFF group according to the revised ASBMR diagnostic criteria for AFF. Moreover, patients who had subtrochanteric or femoral shaft fractures in the same period and met the diagnostic criteria for AFF were recruited and classified into the AFF group. Demographic information, minor features of AFF, comorbidities, history of medication usage, management, and complications were collected and compared among patients with typical PFFs, APFFs, and AFFs.

RESULTS

Eleven PFFs were identified as APFFs, and the prevalence of APFFs among PFFs was 9.4%. Significant differences were found in generalized increase in cortical thickness (p = 0.019), prodromal symptoms (p < 0.001), and the incidence of bilateral fractures (p = 0.010) among the groups, where the incidences of these minor features in the APFF group and the AFF group were higher than those in the typical PFF group. Of note, the duration of fracture healing of APFFs was significantly longer than that of typical PFFs and AFFs (p < 0.001 and p = 0.004, respectively). In addition, the APFF group and the AFF group had higher proportions of patients with rheumatoid arthritis (p = 0.004 and p = 0.027, respectively), bisphosphonate (BP) usage (p = 0.026 and p < 0.001, respectively), and longer duration of BP usage (p = 0.003 and p = 0.007, respectively) than the typical PFF group. Furthermore, significant differences were found in management (p < 0.001) and complication rate (p = 0.020) among the groups, and the rate of complications in the APFF group and the AFF group was higher than that in the typical PFF group.

CONCLUSIONS

APFFs not only fulfilled the mandatory and major diagnostic criteria for AFF but also had many clinical characteristics, management and prognosis distinguishing them from typical PFFs but resembling AFFs; hence, the diagnostic criteria for AFF might be revised to incorporate APFF as a distinct subtype of the condition.

Atypical Metatarsal Fractures: Report of Five Clinical Cases

Atypical fractures are well elucidated when they occur in the femur and are related to the use of bisphosphonates. Prolonged therapy with this drug leads to excessive suppression of bone remodeling, which makes the bone more brittle. In general, they are caused by minimal trauma or are atraumatic. This type of fracture is also reported in other bony sites, such as the metatarsus. Some reports and studies on atypical metatarsal fractures have been published, but further investigations are required to better understand this type of fracture and establish the proper diagnosis, treatment and conduct. The present study is a report of five cases of patients who presented metatarsal fractures during therapy with bisphosphonates. All patients were female, had osteoporosis as a preexisting disease, were taking bisphosphonates, presented fractures that were either atraumatic or caused by minimal trauma, and the imaging examination showed a transverse meta-diaphyseal fracture of the fifth metatarsal shaft with thickening of the lateral cortex, image characteristics similar to the criteria used by the American Society for Bone and Mineral Research (ASMBR) to define atypical femur fractures.

Femora of women with premature ovarian insufficiency exhibit reduced strength and misalignment with the transmitted vertical forces from the upper body

BACKGROUND

Women with premature ovarian insufficiency (POI) lack oestrogen, which is a key determinant of bone growth, epiphyseal closure, and bone tissue organisation. Although dual-energy X-ray absorptiometry (DXA)-derived areal bone mineral density (BMD) remains the gold standard for fracture risk evaluation, it does not fully characterise the skeletal abnormalities present in these women. Hence, we aimed to assess hip/femur anatomy, strength, and geometry and femoral alignment using advanced hip analysis (AHA).

METHODS

We conducted a cross-sectional, case-control study including 89 women with spontaneous normal karyotype POI (s-POI) or iatrogenic POI (i-POI), aged 20-50 years compared with 89 age- and body mass index (BMI)-matched population-based female controls. Hip anatomy, strength, geometrical parameters, and femur alignment were measured using hip DXA images and Lunar AHA software. Femoral orientation angle (FOA) was quantified as the overall orientation of the femur with respect to the axis of the forces transmitted from the upper body.

RESULTS

The median age of POI diagnosis was 35 (18-40) years; the mean POI duration at the time of DXA was 2.07 (range 0-13) years, and 84% of POI women received oestrogen therapy. Areal BMD at all sites was significantly lower in the POI group (all P < .05). Indices of compressive and bending strength were lower in women with POI compared with controls, specifically the cross-sectional area (CSA, mm2) and section modulus (SM, mm3) (139.30 ± 29.08 vs 157.29 ± 22.26, P < .001 and 665.21 ± 129.54 vs 575.53 ± 150.88, P < .001, respectively). The FOA was smaller (124.99 ± 3.18) in women with POI as compared with controls (128.04 ± 3.80; P < .001) at baseline and after adjusting for height and femoral neck BMD.

CONCLUSION

Alongside lower BMD at multiple sites, the femora of women with POI demonstrate reduced strength and a misalignment with forces transmitted from the upper body. Further research is needed to establish the role of these newly identified features and their role in fracture risk prediction in this population.

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.

Osteoporosis: Molecular Pathology, Diagnostics, and Therapeutics

Osteoporosis is a major public health concern affecting millions of people worldwide and resulting in significant economic costs. The condition is characterized by changes in bone homeostasis, which lead to reduced bone mass, impaired bone quality, and an increased risk of fractures. The pathophysiology of osteoporosis is complex and multifactorial, involving imbalances in hormones, cytokines, and growth factors. Understanding the cellular and molecular mechanisms underlying osteoporosis is essential for appropriate diagnosis and management of the condition. This paper provides a comprehensive review of the normal cellular and molecular mechanisms of bone homeostasis, followed by an in-depth discussion of the proposed pathophysiology of osteoporosis through the osteoimmunological, gut microbiome, and cellular senescence models. Furthermore, the diagnostic tools used to assess osteoporosis, including bone mineral density measurements, biochemical markers of bone turnover, and diagnostic imaging modalities, are also discussed. Finally, both the current pharmacological and non-pharmacological treatment algorithms and management options for osteoporosis, including an exploration of the management of osteoporotic fragility fractures, are highlighted. This review reveals the need for further research to fully elucidate the molecular mechanisms underlying the condition and to develop more effective therapeutic strategies.

Surgical strategy of the treatment of atypical femoral fractures

The atypical femoral fracture (AFF) has been attracting significant attention because of its increasing incidence; additionally, its treatment is challenging from biological and mechanical aspects. Although surgery is often required to manage complete AFFs, clear guidelines for the surgical treatment of AFFs are currently sparse. We reviewed and described the surgical treatment of AFFs and the surveillance of the contralateral femur. For complete AFFs, cephalomedullary intramedullary nailing spanning the entire length of the femur can be used. Various surgical techniques to overcome the femoral bowing common in AFFs include a lateral entry point, external rotation of the nail, and the use of a nail with a small radius of curvature, or a contralateral nail. In the case of a narrow medullary canal, severe femoral bowing, or pre-existing implants, plate fixation may be considered as an alternative. For incomplete AFFs, prophylactic fixation depends on several risk factors, such as a subtrochanteric location, presence of a radiolucent line, functional pain, and condition of the contralateral femur; the same surgical principles as those in complete AFFs can be applied. Finally, once AFF is diagnosed, clinicians should recognize the increased risk of contralateral AFFs, and close surveillance of the contralateral femur is recommended.

Bilateral Atypical Femoral Fractures after Bisphosphonate Treatment for Osteoporosis: A Literature Review

INTRODUCTION

This literature review aimed to investigate the incidence, anatomical concerns, etiology, symptoms, diagnostic tools, management, and prognosis of bisphosphonate (BP)-associated bilateral atypical femoral fractures (AFFs).

METHODS

The PubMed, Cochrane Library, Web of Sciences, and CINAHL databases were searched up to 20 March 2022. All cases of bilateral AFFs were included, excluding those without any bisphosphonate treatment information and those in which the femoral fracture did not precisely fit into the diagnostic criteria for AFF.

RESULTS

We identified 43 patients with bilateral AFFs associated with BP use and conducted a comprehensive analysis. Among 43 patients, 29 (67%) had prodromal symptoms. Regarding the simultaneity of fracture, 21 cases (49%) occurred simultaneously, and 22 cases (51%) occurred sequentially. Alendronate was the most commonly used BP treatment (59%). Regardless of the medication type, BP intake duration was more than 5 years in 77%. The initial diagnosis was performed using X-rays in all cases. A total of 53% of patients had complete fractures, and all patients underwent surgical treatment. Among the remaining patients with incomplete fractures, 18% and 29% received surgical and medical treatments, respectively. After BP discontinuation, teriparatide was most commonly used (63%).

CONCLUSIONS

The careful evaluation of relevant imaging findings in patients with thigh/groin pain allows the identification of early incomplete fractures and timely management. Since the rate of contralateral side fractures is also high, imaging studies should be performed on the asymptomatic contralateral side.

Incomplete Diaphyseal Atypical Femoral Fracture due to Increased Anterolateral Bowing: Treatment with Corrective Osteotomy and Intramedullary Nailing with Augmented Plate Fixation

BACKGROUND

Increased anterolateral bowing of the femur is associated with atypical femoral fractures among older patients (including both those receiving and those not receiving treatment with bisphosphonates) as well as a greater likelihood of occurring in the diaphyseal versus the subtrochanteric region. Prophylactic intramedullary (IM) nailing is recommended for the treatment of incomplete atypical femoral fractures, which are radiographically evident. However, this bowing deformity is considered to be a major obstacle to IM nailing as it may be associated with postoperative complications. Corrective osteotomy combined with IM nailing straightens the exaggerated curvature of the femur. We hypothesized that this technique may lead to the safe and rapid healing of incomplete diaphyseal atypical femoral fractures, thereby reducing lateral tensile stress.

METHODS

From October 2015 through March 2020, 17 female patients (20 femora) with a mean age of 76.1 years (range, 68 to 86 years) underwent a surgical procedure for the treatment of an incomplete diaphyseal atypical femoral fracture associated with anterolateral bowing. The surgical technique consisted of minimally invasive osteotomy and reconstruction with use of IM nailing, with or without an augmentation plate. Preoperative and postoperative radiographic findings (lateral and anterior bowing angles, anterolateral bowing grade, and lateral distal femoral angle [LDFA]) were compared. Primary union, time to union, and complications were evaluated as the outcomes.

RESULTS

Primary bone union was achieved in 19 of the 20 femora at a mean of 24.9 weeks (range, 20 to 40 weeks). There were 2 instances of delayed union, which healed at 36 and 40 weeks. The lateral bowing angle, anterior bowing angle, and LDFA significantly improved postoperatively (from 12.0° to 3.3°, from 17.3° to 11.5°, and from 93.5° to 88.8°, respectively) (p < 0.001). There was 1 instance of nonunion, which healed after plate augmentation without a bone graft.

CONCLUSIONS

Given the pathophysiology of elevated lateral tensile stress, corrective osteotomy and IM nailing may be an acceptable solution for the treatment of incomplete diaphyseal atypical femoral fractures associated with increased anterolateral bowing.

LEVEL OF EVIDENCE

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

Recommendations on the post-acute management of the osteoporotic fracture - Patients with "very-high" Re-fracture risk

Osteoporosis is a systemic skeletal disease where there is low bone mass and deterioration of bone microarchitecture, leading to an increased risk of a fragility fracture. The aim of this clinical guideline from Fragility Fracture Network Hong Kong SAR, is to provide evidence-based recommendations on the post-acute treatment of the osteoporotic fracture patient that presents for clinical care at the Fracture Liaison Service (FLS). It is now well established that the incidence of a second fracture is especially high after the first 2 years of the initial osteoporotic fracture. Therefore, the recent osteoporotic fracture should be categorized as “very-high” re-fracture risk. Due to the significant number of silent vertebral fractures in the elderly population, it is also recommended that vertebral fracture assessment (VFA) should be incorporated into FLS. This would have diagnostic and treatment implications for the osteoporotic fracture patient. The use of a potent anti-osteoporotic agent, and preferably an anabolic followed by an anti-resorptive agent should be considered, as larger improvements in BMD is strongly associated with a reduction in fractures. Managing other risk factors including falls and sarcopenia are imperative during rehabilitation and prevention of another fracture. Although of low incidence, one should remain vigilant of the atypical femoral fracture. The aging population is increasing worldwide, and it is expected that the treatment of osteoporotic fractures will be routine. The recommendations are anticipated to aid in the daily clinical practice for clinicians.

The Translational potential of this article

Fragility fractures have become a common encounter in clinical practise in the hospital setting. This article provides recommendations on the post-acute management of fragility fracture patients at the FLS.

Bilateral Subtrochanteric Complete Atypical Femoral Fracture in a Patient With Rheumatoid Arthritis: A Case Report

Antiresorptive drugs such as bisphosphonates (BPs) or denosumab, used for the treatment of osteoporosis over the past decades, have improved bone mineral density and reduced the incidence of fractures. However, there are increasing evidence that atypical femoral fractures (AFFs) are related to long-term use of these medications.

We had experienced bilateral simultaneous subtrochanteric complete AFFs in having rheumatoid arthritis (RA) for 15 years. She just had been taking risedronate for three months prior to this event. Fractures were treated with long cephalomedullary nails. We could get a bone union for the right side at 15 months after index surgery. However, two more surgeries were needed to get bone union for the left side. This study aimed to share our treatment strategy and review of the literature on the correlation between RA and AFFs.

Bilateral Atypical Femur Fractures After Denosumab in a Bisphosphonate Naive Patient: A Case Report

A case report of bilateral atypical femur fractures (AFF) in a bisphosphonate naive patient. A 62-year-old female bisphosphonate naive patient was started on denosumab for osteoporosis. Approximately 3 years later she complained of right hip pain and was found to have a bilateral incomplete AFFs. She was asymptomatic on the left lower limb. Patient was managed conservatively and placed on protected weight bearing on both legs. Symptoms subsequently resolved over a period of 3 months, although radiographic findings remained at approximately 1 year. AFFs may be associated with patients on denosumab therapy even without a prior history of bisphosphonate use. Patients should be counselled appropriately and monitored for such complications.

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.

Adverse events associated with bone-directed therapies in patients with cancer

Bone metastatic disease may lead to serious adverse events in patients with cancer. Bone-directed therapies, including bisphosphonates such as pamidronate and zoledronic acid and the human monoclonal antibody denosumab, are currently approved for the prevention of bone-related adverse events. However, despite the benefits of these drugs, they may cause side effects that are mostly associated with dosages and treatment durations. These side effects range from more frequent, mostly mild, and generally self-limited side effects-such as fever, myalgias, arthralgias, and electrolyte imbalances-to less frequent and more severe side effects such as medication-related osteonecrosis of the jaw and atypical femoral fractures. The purpose of this review is to familiarize clinicians with the literature regarding adverse events associated with bone-directed therapies in patients with cancer. It is important to be aware of these possible adverse events and to educate patients about the predisposing factors associated with side effects from bone-directed therapies and the preventive measures necessary to decrease the risk of occurrence.

Surgical and Pharmacological Management of Periprosthetic Atypical Femoral Fractures: A Narrative Literature Review

Introduction

An increasing number of patients is annually undergoing total hip arthroplasty (THA), and a significant proportion of these patients are elderly and consequently at a higher risk of complications because of age, osteoporosis, and medical comorbidities. Periprosthetic femoral fractures (PFFs) are one of the worst complications of THA associated with high rates of unfavorable prognosis. Besides, in the last decade, a new independent disease entity called “atypical femoral fracture” (AFF) has been identified and defined by the American Society for Bone and Mineral Research (ASBMR) task force. Some PFFs present clinical history and radiographic aspect consistent with an AFF, meeting the ASBMR criteria for the diagnosis of AFF except that PFFs by themselves are an exclusion criterion for AFF. However, there is an increasing number of published studies suggesting that periprosthetic atypical femoral fractures (PAFFs) exist and should not be excluded by definition.

Significance

Nowadays, although there is an increasing interest in PAFFs, there are still very few studies published on the topic and a lack of consensus regarding their treatment. This narrative literature review aims to introduce this new emerging topic to a wider readership describing the characteristics of PAFFs and the state-of-the-art in their management.

Conclusions

Many authors agree that PAFFs should be considered as a subgroup of PFFs that have atypical characteristics; they also show a significant correlation with prolonged bisphosphonate use. A correct diagnosis is paramount for proper treatment of the disease that requires both surgical and medical actions to be taken.

Health-related quality of life outcomes after surgical treatment of atypical femur fractures: a multicenter retrospective cohort study

The objective of this study was to examine the health-related quality of life (HRQOL) outcomes for surgically-treated atypical femur fractures (AFFs) compared to typical femoral diaphyseal fractures. Two large trauma center databases were retrospectively queried for surgically-treated femur fractures. Fractures were grouped into AFFs and compared to a control cohort. Controls for the AFF group included women with diaphyseal fractures without additional AFF characteristics. Patients were contacted for administration of the Short Form-36v2 Health Survey. Surveys were completed an average of 30.3 months (range, 6-138 months) and 25.5 months (range, 5-77 months) postoperatively for the AFF and non-AFF groups, respectively. All patients were female, with 46 patients in the AFF and 26 patients in the non-AFF group. The average age of the AFF group was 70.1 years compared with an average age of 67.4 years in the non-AFF group (p = 0.287). Over 90% (91.3%) of patients in the AFF group had a history of bisphosphonate use while 26.9% of patients in the non-AFF group had used bisphosphonates (p < 0.0001). Patients with AFF reported their postoperative physical and mental health to be no different than similarly aged patients with femoral diaphyseal fractures, as measured by the Short Form 36, version 2 (SF-36v2) Health Survey. These data suggest that mid-term patient-reported quality of life outcomes are similar among women who sustain an AFF compared to a cohort of more typical femoral diaphyseal fractures. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research.

Atypical periprosthetic femoral fractures of the hip: A PRISMA compliant systematic review

INTRODUCTION

Long-term use of bisphosphonates (BPs) is associated with Atypical Femoral Fracture (AFF). Theoretically, periprosthetic femoral fractures (PFF) should be excluded from the diagnosis of AFF. However, recently several studies reported the occurrence of PPFs around a hip arthroplasty presenting features of an AFF. The present study describes the characteristics of Atypical Periprosthetic Femoral Fracture (APFF) and evaluates the effectiveness of their management through a PRISMA compliant systematic review of the published case reports and series.

MATERIALS AND METHODS

A literature search was performed using "periprosthetic fracture" and "atypical femoral fracture" as keywords. Patients demographics, drug use, clinical and imaging characteristics, stem fixation and classification, management strategies for APFF and patients' outcomes, were also collected.

RESULTS

The present review included and analysed 17 patients from 12 studies. All APFFs occurred in females with a mean age of 75.9 years of age (range 43-87). In 11 patients, APFFs occurred around an uncemented stem, and in 6 around a cemented stem. Ten fractures were incomplete, and 7 complete. Conservative management was effective in 4 of 10 patients with incomplete fracture, while all patients with complete fractures underwent open reduction and internal fixation. A fracture non-union was observed in 5 patients and further surgery was required.

DISCUSSIONS

APFFs share several clinical and imaging characteristics with AFF. An appropriate and early diagnosis may allow to improve the outcome of these fractures, the management of which should be based on the same principles of that of AFFs.

CONCLUSIONS

Considering the low quality of published articles and the heterogeneity of the treatment used, a clear recommendation of the most appropriate treatment cannot be formulated.

The Effect of Teriparatide on the Hip: A Literature Review

Teriparatide (TPTD) is a bone-forming agent used to treat postmenopausal osteoporosis. Since hip fractures are related to higher morbidity and mortality rates than other fractures, efficacious osteoporosis drugs for the hip are critical. We reviewed research articles reporting the efficacy of TPTD in terms of bone mineral density (BMD), fractures prevention, changes in the outer diameter, cortical thickness and porosity, post-operative periprosthetic BMD loss, and healing of typical and atypical fractures of the hip. Data meta-analyses indicated that TPTD not only increased the BMD of the proximal femur but also decreased the risk of hip fractures. Even though TPTD increases the cortical bone porosity of the proximal femur, the bone strength does not decrease as the majority of the porosity is located at the endocortex; further, it increases the outer diameter and thickens the cortical bone. TPTD stimulates bone remodeling and facilitates callus maturity and fracture healing. There have been many reports on improving the effect of TPTD on the healing of atypical fractures; therefore it is advisable to use TPTD considering the increase benefit compared to the risk.

Stress Fracture of the Femoral Shaft in Paget's Disease of Bone: A Case Report

Paget’s disease of bone (PDB) is a progressive bone disorder characterized by increased osteoclast-mediated bone resorption and abnormal bone formation. Incomplete atypical femoral fracture, appearing radiographically as a stress fracture at the lateral aspect of the femur, is an uncommon low-trauma fracture frequently seen in association with long-term bisphosphonate therapy. We describe the case of a 61-year-old female patient with PDB who developed a stress fracture at the lateral femoral cortex after 5 doses of intravenous bisphosphonate. The conservative treatment plan included discontinuation of bisphosphonate, a continuation of calcium and vitamin D supplementation, and limited weight-bearing for 3 months. The patient’s pain level gradually improved after switching to the new treatment plan. At the latest follow-up, approximately 5 years after the initiation of conservative treatment, the patient remained pain-free, and her PDB was well-controlled. However, the fracture line was still visible on the most recent radiograph. Although it remains unclear whether a stress fracture at the lateral femoral cortex occurred due to bisphosphonate therapy or PDB, this case highlights the importance of careful evaluation of any lesion that appears in PDB patients receiving bisphosphonate therapy.

The safety profile of denosumab in oncology beyond the safety of denosumab as an anti-osteoporotic agent: still more to learn

INTRODUCTION

Initially endorsed as an antiosteoporotic agent, denosumab ‒ human monoclonal antibody inhibiting the receptor activator of nuclear factor kappa-B ligand (RANKL)‒ has currently shown an anticancer potential, rationalizing its exploitation in oncology. A prerequisite for leveraging denosumab in oncology is a favorable safety profile.

AREAS COVERED

The present review provides an overview of the adverse events of denosumab in oncology, with a focus on hypocalcemia, medication-related osteonecrosis of the jaw, atypical femoral fracture(s), post-denosumab vertebral fractures, increased risk of infections, and excess of second primary cancer. Representative studies addressing the safety and efficacy of denosumab compared to bisphosphonates in oncology are summarized. Critical gaps in the literature concerning the safety of denosumab in oncology are highlighted as opposed to plenty of available safety data on denosumab as an antiosteoporotic agent.

EXPERT OPINION

Despite the generally acceptable safety profile of denosumab in oncology, many issues remain unresolved. Further research is mandatory to counteract current challenges, namely: (i) validation of risk factors for adverse events; (ii) elucidation of the pathophysiology of the adverse events in search of actionable molecular pathways; (iii) illumination of the association of denosumab with increased risk of infections and/or second primary cancer; (iv) establishment of optimal diagnostic, and therapeutic protocols.

Risk of complete atypical femur fracture with Oral bisphosphonate exposure beyond three years

Background

Bisphosphonate (BP) therapy has been associated with atypical femur fracture (AFF). However, the threshold of treatment duration leading to increased AFF risk is unclear. In a retrospective cohort of older women initiating BP, we compared the AFF risk associated with treatment for at least three years to the risk associated with treatment less than three years.

Methods

We used observational data from a large population of female members of an integrated healthcare system who initiated oral BP during 2002–2014. Women were retrospectively followed for incident AFF confirmed by radiologic adjudication. Demographic data, pharmacologic exposures, comorbidity, bone density, and fracture history were ascertained from electronic health records. Inverse probability weighting was used to estimate risk differences comparing the cumulative incidence (risk) of AFF if women discontinued BP within three years to the cumulative incidence of AFF if women continued BP for three or more years, adjusting for potential time-dependent confounding by the aforementioned factors.

Results

Among 87,820 women age 45–84 years who initiated BP (mean age 68.6, median T-score − 2.6, 14% with prior major osteoporotic fracture), 16,180 continued BP for three or more years. Forty-six confirmed AFFs occurred during follow-up in the two groups. AFF-free survival was greater for BP treatment < 3 years compared to treatment ≥3 years (p = 0.004 comparing areas under survival curves). At five years, the risk of AFF was 27 per 100,000 (95% confidence interval, CI: 8–46) if women received BP treatment < 3 years and 120 per 100,000 (95% CI: 56–183) if women received BP treatment ≥3 years (risk difference 93 per 100,000, 95% CI: 30–160). By ten years, the risks were 27 (95% CI: 8–46) and 363 (95% CI: 132–593) per 100,000 for BP treatment < 3 and ≥ 3 years, respectively (risk difference 336 per 100,000, 95% CI: 110–570).

Conclusions

Bisphosphonate treatment for 3 or more years was associated with greater risk of AFF than treatment for less than 3 years. Although AFFs are uncommon among BP-treated women, this increased risk should be considered when counseling women about long-term BP use. Future studies should further characterize the dose-response relationship between BP duration and incident AFF and identify patients at highest risk.

Atypical periprosthetic femoral fractures of the hip: characterisation of three cases

INTRODUCTION

Long-term use of bisphosphonates (BPs) has been associated with a specific type of tensile side femoral stress fracture known as Atypical Femoral Fracture (AFF). Theoretically periprosthetic femoral fractures (PFF) should be excluded from the diagnosis of AFF. However, emerging evidence correlates prolonged BPs use with the occurrence of a type of PFF with an atypical pattern (atypical PFF, APFF). The aim of the present study is to report 3 cases of APFF treated at a single centre.

METHODS

Clinical and radiographic records of PFF that occurred between January 2016 and August 2018 were retrospectively reviewed. All patients meeting the American Society for Bone and Mineral Research (ASBMR) criteria for definition of PFF were included. Management strategies for APFF and patient outcomes, including fracture healing and hip function (assessed by the Oxford Hip Score [OHS]) were collected.

RESULTS

3 patients in the study period were identified as APFF (1 incomplete, 2 complete). All patients were females with a mean age of 83.3 years. All patients were treated with lateral plating. The application of a contralateral strut allograft resulted in fracture healing in cases of complete fractures. Mean OHS at final follow-up was 34.3.

CONCLUSIONS

Despite occurring around a hip stem like PFF, APFF had peculiar clinical and radiographic features, making them more similar to AFF. Therefore, the orthopaedic surgeon should also consider the natural history and healing problems associated with AFF prior in order to choose the most appropriate management for APFF.

Multiple ipsilateral femoral stress fractures in a patient taking denosumab for osteoporosis-a case report

This is the first report describing three ipsilateral femoral stress fractures in a patient taking denosumab.

INTRODUCTION

Multiple reports of atypical femur fractures (AFF) in patients receiving denosumab have emerged recently. Denosumab is an anti-resorptive agent approved for treatment of osteoporosis. It is a human monoclonal antibody which blocks osteoclast activation, maturation, and function.

METHODS

This is a case report of a 74-year-old female patient who sustained three stress fractures of her left femur.

RESULTS

The patient healed her fractures after intramedullary nailing of the femur and was able to return to her activities.

CONCLUSIONS

High index of suspicion is needed in any patient with osteoporosis on denosumab complaining of thigh or groin pain. Careful examination and radiographic studies of both femurs are warranted if AFF is discovered.

Atypical Subtrochanteric Femur Fracture and Hip Osteoarthritis Treated with a Revision Monoblock Stem and Strut Allograft: A Case Report

CASE

A 73-year-old woman was diagnosed with a nondisplaced incomplete atypical bisphosphonate-related subtrochanteric femur fracture and ipsilateral hip osteoarthritis. She was treated with a total hip arthroplasty using a monoblock revision stem and a strut allograft to provide adjunctive mechanical and biological support. At the final follow-up, the patient had no pain, the stem was well fixed, and the allograft strut had incorporated; however, a persistent fracture line was noted.

CONCLUSION

When an atypical femur fracture coexists with hip osteoarthritis, total hip arthroplasty may be a reasonable treatment option to address the fracture and concomitant hip osteoarthritis with a single surgical intervention. However, consideration should be given to using a stem with distal fixation and augmenting the construct with a strut allograft.

Bilateral Atypical Femur Fractures Complicated by Carbon Fiber Cephalomedullary Nail Fracture: A Case Report

CASE

A 69-year-old woman with a history of breast cancer, on long-term antiresorptive medications, was treated with carbon fiber cephalomedullary nails for bilateral atypical femur fractures. Her thigh pain was presumed to be from metastatic lesions and was treated with radiation without standard imaging. The index procedure was complicated by a left nail fracture. The patient underwent exchange cephalomedullary nail fixation with plate augmentation. At 1 year, the patient was asymptomatic with radiographs demonstrating healing.

CONCLUSION

This case highlights the importance of appropriate imaging in all patients with thigh pain on antiresorptive therapy and features an uncommon complication of carbon fiber cephalomedullary nail fixation.

Clinical Features and Outcomes of Bilateral Atypical Femoral Fractures

Bilateral atypical femoral fractures (AFFs) are relatively rare. In this report, we retrospectively researched clinical features and outcomes of bilateral AFFs treated at our institution. We previously treated 4 patients (8 limbs) with intramedullary nailing for complete AFFs (6 limbs) and incomplete AFFs (2 limbs). The mean age at the first operation was 53.3 years, and all patients were female. Of the 4 patients, two had breast cancer, and another two had systemic lupus erythematosus. Three of them received bisphosphonates, and 2 received denosumab, proton pump inhibitor, or glucocorticoid therapy. Only 2 of 6 cases of incomplete AFFs had prodromal pain before progressing to complete fracture. The mean interval from the first surgery to contralateral fracture or prophylactic surgery was 16 months. Radiographically, complete bone union was achieved in 6 limbs. However, a small gap at the lateral cortex of fracture site remained in 2 limbs. Finally, all of the patients were pain-free and able to walk without a cane. It is absolutely necessary to confirm contralateral femoral conditions; however, prediction of progression to complete fracture based solely on prodromal pain was difficult. Therefore, we should advise patients about the danger of progression to complete AFFs even if they are asymptomatic, and a prophylactic surgery should be performed after obtaining informed consent.

Repurposing denosumab in lung cancer beyond counteracting the skeletal related events: an intriguing perspective

INTRODUCTION

Repurposing denosumab in lung cancer therapeutics capitalizes on its well-established role in preventing the skeletal related events (SREs) and its emerging, yet elusive, bone-independent role, assigned to inhibit the contribution of RANKL to cancer initiation and progression.

AREAS COVERED

The present review presents the available preclinical and clinical data indicating that denosumab may provide survival benefit to lung cancer patients beyond the counteraction of SREs.

EXPERT OPINION

Despite the preliminary data heralding the potential of denosumab to increase overall survival in lung cancer, the embracement of this strategy in clinical practice cannot be advocated until large randomized clinical trials consolidate its safety and efficacy. Given the improvement of lung cancer prognosis ascribed to revolutionary targeted treatment agents, the possibility of denosumab-related increased risk of second primary malignancies merits further evaluation. Many challenges in endorsing denosumab as a strategy to treat lung cancer beyond SREs prevention are pending counteraction, including: (i) patient selection guided by validated predictive and prognostic biomarkers; (ii) assessment of long-term outcomes; (iii) evaluation of benefit-risk ratio; (iv) translational research; (v) combination of denosumab with other targeted therapies; (vi) integration of genomic biomarkers, immune-related biomarkers, and biomarkers of active RANKL pathway to guide the decision-making process.

Microindentation: A New Technique for Bone Quality Assessment

Fractures are the result of the application of a greater force on bone than its strength. Therefore, to understand fracture physiopathology, it is essential to know bone strength determinants. These include bone mineral density (BMD), bone spatial structure (bone geometry and microarchitecture) and bone mechanical and tissue properties. While BMD and bone spatial structure can be easily evaluated through imaging technology, assessment of bone tissue and mechanical properties is complex and typically requires invasive techniques that are not suitable in clinical practice. Microindentation is a relatively recently developed technique that directly measures bone tissue and mechanical properties in patients in a fast, safe, feasible and minimally invasive way. It appears to be particularly informative in diseases associated with an increased risk of fracture not explained by BMD values as occurs in X-linked hypophosphataemia (XLH). The aim of this article is to provide an overview on bone microindentation and its potential utility in the evaluation of patients with XLH.

Bisphosphonate drug holidays: One size does not fit all

Bisphosphonates have been safely used to treat osteoporosis, effectively reducing fracture risk after 3 to 5 years of treatment. Recent concerns about long-term safety coupled with posttreatment fracture risk reduction have increased support for drug holidays. The decision to start low-risk patients on drug holidays must be based on current fracture risk assessment.

Case of atypical femoral fractures that mimicked the typical imaging findings of prostate cancer-induced bone metastasis

INTRODUCTION

Atypical femoral fractures are atraumatic or minimally traumatic fractures and rare side effects of bone resorption inhibitors. Bone resorption inhibitors are frequently used in the treatment of prostate cancer.

CASE PRESENTATION

A 62-year-old man complained of difficulty in walking and left lower limb pain. Androgen deprivation and denosumab therapy for prostate cancer-induced bone metastasis was initiated 27 months ago. Even though the prostate-specific antigen level did not increase, imaging studies indicated the possibility of bone metastasis. The patient underwent bone biopsy; however, no malignancy was detected. Afterward, he had a fall, causing a complete fracture in his left femur.

CONCLUSION

Atypical femoral fractures occasionally mimic typical imaging findings and outcomes of bone metastasis. This case is important for recognizing such cases.

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.

Atypical femoral fracture in the setting of alendronate treatment for osteoporosis: a case report and literature review

Osteoporosis leads to reduced bone mass and disrupted bone architecture. Bisphosphonates are used to treat osteoporosis by inhibiting bone resorption. Chronic bisphosphonate use has been associated with adverse effects including atypical femoral fractures (AFF). We report the case of a 63-year-old woman with a history of osteoporosis treated with alendronate, who presented with bilateral hip and groin pain. Radiography detected a chronic-appearing callus in the left hip concerning for a chronic stress fracture versus malignancy. Initial imaging could not rule out malignancy, prompting positron emission tomography (PET) and bone biopsy. PET scan was negative for malignancy and biopsy found changes consistent with chronic bisphosphonate use. This prompted prophylactic intramedullary nailing of the femur. This case highlights the importance of considering AFF in patients with a history of hip pain in the setting of chronic BPs use and reviews criteria within the literature to manage patients with AFFs.

Surgical Fixation of Atypical Femur Fractures in Bisphosphonate-treated Patients

Objective

To evaluate the outcomes of the surgical fixation of atypical femoral fractures in bisphosphonate-treated patients with an intramedullary device.

Materials and methods

This multicentric study was carried out at the department of orthopedics, Dr. Ruth Phau Civil Hospital and Medicare Hospital, Karachi, Pakistan, between 2013 and 2018. In this retrospective observational study, we reviewed 10 bisphosphonate-treated patients, fixed surgically with an intramedullary nail after presenting with radiologically characteristic atypical femur fractures identified according to the American Society for Bone and Mineral Research criteria. We excluded patients with fractures sustained by high-energy trauma, road traffic accidents, fall from a height, and those associated with underlying malignancy.

Results

A total of 11 atypical femoral fractures in 10 patients were included, all of whom were females with a mean age of 68.6 (range 57-82) years. Out of 11 fractures, 81.8% (n=9) were located in the subtrochanteric region and two were located in the femoral shaft. The mean bisphosphonate use was 58.3 months. All patients were treated with intramedullary devices; an intramedullary interlocking nail in two cases and proximal femoral nail antirotation in nine cases. The mean follow-up duration was 12 months. All fractures were united in an average time of 9.9 months (range 6 - 16 months). Implant failure and/or nonunion were not observed, whereas delayed union was noted in five patients.

Conclusion

Intramedullary fixation is a reliable method for the treatment of atypical femur fractures in bisphosphonate-treated patients owing to its intramedullary placement. These devices act as an internal splint and can provide much more axial stability, reducing the risk of implant fatigue failure due to a delay in fracture healing from prolonged bisphosphonate use.

Prophylactic Fixation Can Be Cost-effective in Preventing a Contralateral Bisphosphonate-associated Femur Fracture

BACKGROUND

Bisphosphonates reduce the risk of fractures associated with osteoporosis but increase the risk of atypical subtrochanteric femur fractures. After unilateral atypical femur fracture, there is risk of contralateral fracture, but the indications for prophylactic fixation are controversial.

QUESTIONS/PURPOSES

The purpose of this study is to use Markov modeling to determine whether contralateral prophylactic femur fracture fixation is cost-effective after a bisphosphonate-associated atypical femur fracture and, if so, what patient-related factors may influence that determination.

METHODS

Markov modeling was used to determine the cost-effectiveness of contralateral prophylactic fixation after an initial atypical femur fracture. Simulated patients aged 60 to 90 years were included and separated into standard and high fracture risk cohorts. Patients with standard fracture risk were defined as those presenting with one atypical femur fracture but without symptoms or findings in the contralateral femur, whereas patients with high fracture risk were typified as those with more than one risk factor, including Asian ethnicity, prodromal pain, femoral geometry changes, or radiographic findings in the contralateral femur. Outcome probabilities and utilities were derived from studies matching to patient characteristics, and fragility fracture literature was used when atypical femur fracture data were not available. Associated costs were largely derived from Medicare 2015 reimbursement rates. Sensitivity analysis was performed on all model parameters within defined ranges.

RESULTS

Prophylactic fixation for a 70-year-old patient with standard risk for fracture costs USD 131,300/quality-adjusted life-year (QALY) and for high-risk patients costs USD 22,400/QALY. Sensitivity analysis revealed that prophylaxis for high-risk patients is cost-effective at USD 100,000/QALY when the cost of prophylaxis was less than USD 29,400, the probability of prophylaxis complications was less than 21%, or if the patient was younger than 89 years old. The parameters to which the model was most sensitive were the cost of prophylaxis, patient age, and probability of prophylaxis-related complications.

CONCLUSIONS

Prophylactic fixation of the contralateral side after unilateral atypical femur fracture is not cost-effective for standard-risk patients but is cost-effective among high-risk patients between 60 and 89 years of age with a high risk for an atypical femur fracture defined by patients with more than one risk factor such as Asian ethnicity, prodromal pain, varus proximal femur geometry, femoral bowing, or radiographic changes such as periosteal beaking and a transverse radiolucent line. However, our findings are based on several key assumptions for modeling such as the probability of fractures and complications, the costs associated for each health state, and the risks of surgical treatment. Future research should prospectively evaluate the degree of risk contributed by known radiographic and demographic parameters to guide management of the contralateral femur after a patient presents with an atypical femur fracture.

LEVEL OF EVIDENCE

Level III, economic and decision analyses.

[Management of osteoporosis after fragility fractures]

Osteoporosis is defined as a systemic bone disease with decreased bone strength and an increased susceptibility for fractures. Older people in particular face an increased risk of fractures. These kind of fractures are usually caused by an inadequate trauma and are the so-called fragility fractures. In older adults immediate fracture stabilization and early mobilization have become the standard procedure after a fragility fracture. Treatment of the underlying osteoporosis often plays a minor role in clinical practice. Only a small group of patients are already under osteoporosis medication and even after a fracture occurs only few patients receive osteoporosis drug treatment with the aim to reduce the progression of osteoporosis and to reduce subsequent fractures. In the literature this has been described as the osteoporosis care gap. The following article presents an overview of treatment options and answers many different questions from the clinical routine.

A review of atypical subtrochanteric femoral fractures in Northern Ireland between 2010 and 2014

The term atypical femoral fractures most commonly occur in the subtrochanteric area. Concerns exist regarding the role of bisphosphonate treatment in their aetiology. Which surgical intervention provides the best outcome remains contentious. We reviewed all atypical subtrochanteric femoral fractures treated in Northern Ireland over 5 years, specifically investigating incidence, prodromal symptoms, association with bisphosphonates and optimal fixation methods. All subtrochanteric fractures treated in the region were identified and reviewed for atypical features. Case notes and imaging were then reviewed for each patient. A total of 364 subtrochanteric femoral fractures were identified during the 5-year study period. Twenty-six of these met the criteria for an atypical fracture (7%). Thirteen patients (50%) had presented with prodromal symptoms prior to complete fracture, six of which had radiological evidence of an incomplete fracture of the lateral cortex. Thirteen patients had a history of bisphosphonate treatment. All were treated operatively, with twenty-five cephalomedullary nails and one dynamic hip screw. Twenty-one patients had follow-up for greater than 2 months, nine of which (42.9%) achieved radiological union with a mean time to union of 297 days. Dynamically locked nails had a higher union rate than statically locked (80% versus 33.3%). Four patients required major revision surgery (15.4%). The quality of reduction was statistically significant in predicting need for revision. Atypical fractures often present with prodromal symptoms. Complete fractures are difficult to successfully manage with longer than expected times to union. Treatment with a dynamically locked, cephalomedullary with a good reduction provided the best results.

Atypical Femoral Fractures: Implications for the Advanced Practitioner in Oncology

Bone-health issues may arise for oncology patients as a side effect of their treatments. One of these may be the development of an atypical femoral fracture. Advanced practitioners should be aware of the risk factors for atypical femoral fractures, and be able to promptly recognize signs, provide patient education, and manage them competently.