Bisphosphonate-related atypical femoral fracture: Managing a rare but serious complication

Qianggu concentrate: unlocking bone protection power via antioxidative SIRT1/NRF2/HO-1 pathways in type 2 diabetic osteoporosis

Background

Qianggu Concentrate (QGHJ), a traditional Chinese medicine, is extensively used to treat Type 2 Diabetic Osteoporosis (T2DOP). Despite its widespread use, research on its therapeutic mechanisms within T2DOP is notably scarce.

Objective

To explore QGHJ's osteoprotection in T2DOP rats and BMSCs, focusing on the antioxidant activation of SIRT1/NRF2/HO-1 and NRF2 nuclear migration.

Methods

QGHJ constituent analysis was performed using UPLC-HRMS. Safety, bone-health efficacy, and glucose metabolic effects in T2DOP rats were evaluated via general condition assessments, biomarker profiling, micro-CT, biomechanics, staining methods, and ELISA, supplemented by RT-qPCR and Western blot. BMSCs' responses to QGHJ under oxidative stress, including viability, apoptosis, and osteogenic differentiation, were determined using CCK-8, flow cytometry, ALP/ARS staining, and molecular techniques. The modulation of the SIRT1/NRF2/HO-1 pathway by QGHJ was explored through oxidative stress biomarkers, immunofluorescence, and Western blot assays.

Results

UPLC-HRMS identified flavonoids, monoterpenes, and isoflavones as QGHJ's key compounds. In vivo, QGHJ proved safe and effective for T2DOP rats, enhancing bone mineral density, microenvironment, and biomechanical properties without impairing vital organs. It modulated bone markers PINP, TRACP 5b, RUNX2 and PPARγ, favoring bone anabolism and reduced catabolism, thus optimizing bone integrity. QGHJ also regulated glycemia and mitigated insulin resistance. In vitro, it preserved BMSCs' viability amidst oxidative stress, curbed apoptosis, and fostered osteogenesis with regulated RUNX2/PPARγ expression. Mechanistic insights revealed QGHJ activated the SIRT1/NRF2/HO-1 pathway, augmented NRF2 nuclear translocation, and enhanced the antioxidative response, promoting bone health under stress.

Conclusion

In T2DOP rat and BMSCs oxidative stress models, QGHJ's bone protection is anchored in its antioxidative mechanisms via the SIRT1/NRF2/HO-1 pathway activation and NRF2 nuclear translocation.

Clinical characteristics, densitometric parameters and outcomes of patients with atypical femoral fractures related to bisphosphonate treatment for osteoporosis

PURPOSE

We described the clinical and densitometric characteristics and treatment outcomes of patients who developed atypical femoral fractures (AFF) while on bisphosphonate for osteoporosis.

METHODS

We performed a retrospective cohort study including all adults aged ≥50 years who developed AFF while on bisphosphonates between 1 January 2008 and 31 December 2020, and subsequently managed in the Osteoporosis Centre at Queen Mary Hospital in Hong Kong. A control group of patients who developed fragility hip fractures while on bisphosphonates in the same period was included for comparison. We compared the clinical and densitometric characteristics between the two groups, and described the clinical outcomes for the AFF group.

RESULTS

In total, 75 patients were included (AFF: n = 35; fragility hip fracture: n = 40). All were related to oral bisphosphonates. The AFF group was characterised by a longer duration of bisphosphonate use (median of 5 years), higher bone mineral density (BMD) and more acute neck-shaft angle (all p < 0.05). Following AFF, 8 patients (22.9%) did not receive any subsequent bone-active agents: due to refusal to use an injectable, or BMD out of osteoporotic range. Most of those who received bone-active agents were given teriparatide, followed by raloxifene, and achieved stable BMD. However, subsequent fragility risk remained high. Nonetheless, AFF did not confer excess morbidity and mortality.

CONCLUSION

AFF was characterised by usually long duration of bisphosphonate use, higher BMD and more acute neck-shaft angle. AFF did not confer significant impairment in mobility or mortality. Nonetheless, further research work is necessary to optimise bone health among patients who develop AFF.

Bisphosphonate-induced atypical femoral shaft fracture: A case report

Osteoporosis is an important cause of fractures in postmenopausal women. Bisphosphonates are the first line of treatment for osteoporosis. However, long-term use of these medications has been related to atypical femoral fractures (AFF). We present a case of a 71-year-old postmenopausal woman, with a history of osteoporosis being treated with bisphosphonates for 6 years. The patient developed pain in her left hip and thigh over a period of 3-4 months. Radiographic studies showed an AFF and she was managed conservatively. Stopping bisphosphonate therapy should be an initial step in managing or limiting the progression of AFF. A drug holiday should be considered in patients who have been treated for more than 3-5 years to prevent AFFs. The risk of developing AFFs should never be ignored in this subset of patients.

Bisphosphonates and Atypical Femur Fractures: Is the Relationship Causal or Casual?

Bisphosphonates (BPs) are a time-tested drug class with multivariate use cases. They are used in pathologies ranging from osteoporosis to Paget's disease, and also help in accelerated fracture healing. They have been used to treat both benign and malignant lesions of the skeletal system since a long time. However, there have been reports of increased incidences of atypical femoral fractures (AFFs) in patients exhibiting chronic use of bisphosphonates in the past years. This has led to the widespread dissuasion of physicians and practitioners from using the drug class. By means of this review of the literature, the authors aim to investigate the relationship between BP use and its association with AFFs. The review focuses on and elucidates the basic pharmacology of BPs and goes on to illustrate the indications of BPs in various pathologies of the musculoskeletal system, further exploring the effects of BPs on the healing of various bony fractures. The authors also explore the incidences of other pathologies, such as osteonecrosis of the jaw and nephropathies associated with BP use, and elaborate on their features. Through this review, the authors have tried to educate and induce critical thinking on the part of clinicians and medical professionals in regard to prescribing BPs to patients that need them, by keeping in mind the risk-reward relationship that accompanies their use.

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.

Position Statement: Atypical Femoral Fracture from the Korean Society for Bone and Mineral Research in 2023

As the aging population increases, the number of patients with osteoporosis is gradually rising. Osteoporosis is a metabolic bone disease characterized by low bone mass and the microarchitectural deterioration of bone tissue, resulting in reduced bone strength and an increased risk of low-energy or fragility fractures. Thus, the use of anti-resorptive agents, such as bisphosphonates (BPs), to prevent osteoporotic fractures is growing annually. BPs are effective in reducing hip and other fractures. However, the longer a patient takes BPs, the higher the risk of an atypical femoral fracture (AFF). The exact mechanism by which long-term BP use affects the development of AFFs has not yet been clarified. However, several theories have been suggested to explain the pathogenesis of AFFs, such as suppressed bone remodeling, impaired bone healing, altered bone quality, and femoral morphology. The management of AFFs requires both medical and surgical approaches. BPs therapy should be discontinued immediately, and calcium and vitamin D levels should be evaluated and supplemented if insufficient. Teriparatide can be used for AFFs. Intramedullary nailing is the primary treatment for complete AFFs, and prophylactic femoral nailing is recommended if signs of an impending fracture are detected.

Twelve Months of Denosumab and/or Alendronate Is Associated With Improved Bone Fatigue Life, Microarchitecture, and Density in Ovariectomized Cynomolgus Monkeys

Prolonged use of antiresorptives such as the bisphosphonate alendronate (ALN) and the RANKL inhibitor denosumab (DMAb) are associated with rare cases of atypical femoral fracture (AFF). The etiology of AFF is unclear, but it has been hypothesized that potent osteoclast inhibitors may reduce bone fatigue resistance. The purpose of this study was to quantify the relationship between antiresorptive treatment and fatigue life (cycles to failure) in bone from ovariectomized cynomolgus monkeys. We analyzed humeral bone from 30 animals across five treatment groups. Animals were treated for 12 months with subcutaneous (sc) vehicle (VEH), sc DMAb (25 mg/kg/month), or intravenous (iv) ALN (50 μg/kg/month). Another group received 6 months VEH followed by 6 months DMAb (VEH-DMAb), and the final group received 6 months ALN followed by 6 months DMAb (ALN-DMAb). A total of 240 cortical beam samples were cyclically tested in four-point bending at 80, 100, 120, or 140 MPa peak stress. High-resolution imaging and density measurements were performed to evaluate bone microstructure and composition. Samples from the ALN (p = 0.014), ALN-DMAb (p = 0.008), and DMAb (p < 0.001) groups illustrated higher fatigue-life measurements than VEH. For example, at 140 MPa the VEH group demonstrated a median ± interquartile range (IQR) fatigue life of 1987 ± 10593 cycles, while animals in the ALN, ALN-DMAb, and DMAb groups survived 9850 ± 13648 (+395% versus VEH), 10493 ± 16796 (+428%), and 14495 ± 49299 (+629%) cycles, respectively. All antiresorptive treatment groups demonstrated lower porosity, smaller pore size, greater pore spacing, and lower number of canals versus VEH (p < 0.001). Antiresorptive treatment was also associated with greater apparent density, dry density, and ash density (p ≤ 0.03). We did not detect detrimental changes following antiresorptive treatments that would explain their association with AFF. In contrast, 12 months of treatment may have a protective effect against fatigue fractures. © 2022 American Society for Bone and Mineral Research (ASBMR).

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.

Atypical Vancouver B1 Periprosthetic Fractures: The Unsolved Problem

Atypical femoral fractures (AFF) are stress or insufficiency fractures induced by low energy trauma or no trauma, frequently correlated with prolonged bisphosphonate therapy. The diagnosis follows major and minor criteria, originally described by the Task Force of the American Society for Bone and Mineral Research in 2010 and updated in 2014. However, the definition of AFFs in the report excluded periprosthetic fractures. When atypical fractures occur close to a prosthetic implant the situation become critical, the surgical treatment is often demolitive and supported by medical treatment. Moreover, acute ORIF as a first line treatment is frequently burdened by a high failure rate , and often a stem revision is required as second line treatment. The healing process is long and difficult with poor functional results and impairing outcomes. We present a case treated at our institution of a 78 year old woman with a history of a femoral atypical periprosthetic fracture, complicated by multiple surgical revisions. Its arduous management reflects all the difficulties that these type of fractures could present to the surgeon, while its good final result may teach us how to approach them in a correct way.

Effect of Vitamin E Supplement on Bone Turnover Markers in Postmenopausal Osteopenic Women: A Double-Blind, Randomized, Placebo-Controlled Trial

Vitamin E is a strong anti-oxidative stress agent that affects the bone remodeling process. This study evaluates the effect of mixed-tocopherol supplements on bone remodeling in postmenopausal osteopenic women. A double-blinded, randomized, placebo-controlled trial study was designed to measure the effect of mixed-tocopherol on the bone turnover marker after 12 weeks of supplementation. All 52 osteopenic postmenopausal women were enrolled and allocated into two groups. The intervention group received mixed-tocopherol 400 IU/day, while the control group received placebo tablets. Fifty-two participants completed 12 weeks of follow-up. Under an intention-to-treat analysis, vitamin E produced a significant difference in the mean bone resorption marker (serum C-terminal telopeptide of type I collagen (CTX)) compared with the placebo group (-0.003 ± 0.09 and 0.121 ± 0.15, respectively (p < 0.001)). In the placebo group, the CTX had increased by 35.3% at 12 weeks of supplementation versus baseline (p < 0.001), while, in the vitamin E group, there was no significant change of bone resorption marker (p < 0.898). In conclusion, vitamin E (mixed-tocopherol) supplementation in postmenopausal osteopenic women may have a preventive effect on bone loss through anti-resorptive activity.

Bilateral Cemented Custom-Made Total Hip Arthroplasty in Paget's Disease with Femoral Cortical Thickening and Canal Narrowing

In this report, we present a case of a 57-year-old man complaining of pain in both his hips. Clinically, the patient reported lameness and reduction in the range of motion of the hips. Radiographic imaging showed a very narrow medullary femoral canal, confirmed by a computed tomography scan. In consideration of the narrowness of the femoral canal and cortex thickening, and due to the rarity of the clinical case, we opted to use a custom-made prosthesis. We performed total hip arthroplasty, initially on the right side. One year later, we repeated the procedure on the left side. One year after the last surgery, the patient reported well-being and continuous improvement in walking, with no complications. This case report highlights the features and the critical issues related to this kind of surgery in patients affected by Paget's disease of the bone and the importance of custom-made implants in challenging cases.

Updated approach for the management of osteoporosis in Turkey: a consensus report

As a result of the current demographics, increased projections of osteoporosis (OP) and prevalence of the disease in Turkey, a panel of multidisciplinary experts developed a thorough review to assist clinicians in identifying OP and associated fracture risk patients, diagnosing the disease with the appropriate available diagnostic methods, classifying the disease, and initiating appropriate treatment. The panel expects to increase the awareness of this prevalent disease, decrease consequences of OP with corresponding cost savings and, ultimately, decrease the overall burden of OP and related fractures in Turkey.

BACKGROUND

OP is not officially accepted as a chronic disease in Turkey despite the high prevalence and predicted increase in the following years. However, there are areas where the country is performing well, such as having a country-specific fracture risk assessment model, DXA access, and the uptake of FRAX. Additional efforts are required to decrease the existing treatment gap estimating 75-90% of patients do not receive pharmacological intervention for secondary prevention, and the diagnosis rate is around 25%.

METHODS

A selected panel of Turkish experts in fields related to osteoporosis was provided with a series of relevant questions to address prior to the multi-day conference. Within this conference, each narrative was discussed and edited by the entire group, through numerous drafts and rounds of discussion until a consensus was achieved. Represented in the panel were a number of societies including The Turkish Osteoporosis Society, The Society of Endocrinology and Metabolism of Turkey (SEMT), and The Turkish Society of Physical Medicine and Rehabilitation.

RESULTS

Standardized general guidelines to identify OP and related fractures and at-risk population in Turkey, which will enable clinicians to accurately and effectively diagnose the disease, treat the appropriate patients with available pharmacological and non-pharmacological treatments and decrease the burden of the disease.

CONCLUSIONS

This manuscript provides a review of the current state of OP and related fractures in Turkey. Moreover, this manuscript reviews current international guidelines and national studies and proposes a number of helpful country-specific classifications that can be used by healthcare providers caring for the at-risk population. Additionally, the panel proposes practical recommendations that should be implemented nationally in order to decrease the burden of OP and related fractures and effectively preventing the burden in future generations.

Clinical effects of switching from minodronate to denosumab treatment in patients with postmenopausal osteoporosis: a retrospective study

Background

Denosumab is a major treatment option for patients with postmenopausal osteoporosis; however, the evidence for its use is lacking. Therefore, in this 24-month retrospective study, we aimed to evaluate the effects of switching from minodronate (MIN) to denosumab in these patients.

Methods

Patients with postmenopausal osteoporosis either switched from MIN to denosumab (Group 1; n = 32) or continued MIN treatment (Group 2; n = 24). Bone mineral density (BMD) of the lumbar spine (L2–L4) and femoral neck was assessed at baseline and every 6 months for 24 months. Serum bone-specific alkaline phosphatase (BAP) and N-terminal telopeptide were measured at baseline, 12 months, and 24 months.

Results

Twenty-nine of the 32 patients (90.6%) in group 1 and all patients (24/24) in group 2 completed the 24-month follow-up. Switching from MIN to denosumab (Group 1) significantly increased lumbar BMD at 12, 18, and 24 months (6.1, 7.4, and 9.6%, respectively) and femoral neck BMD at 12, 18, and 24 months (2.8, 3.2, and 3.4%, respectively), whereas MIN continuous treatment (Group 2) showed no significant difference from baseline. Switching therapy also showed a significant decrease in serum BAP from baseline to 12 and 24 months (− 19.3 and − 26.5%, respectively) and serum NTX from baseline to 12 months (− 13.1%), whereas continuous MIN treatment failed to show any significant differences from baseline.

Conclusion

Switching from MIN to denosumab in patients with postmenopausal osteoporosis showed clinical benefits with regard to BMD and bone turnover markers in comparison with continuous MIN treatment. It may therefore be a valid treatment option in the clinical setting.

Impending Atypical Femur Fracture Presenting as Painful Total Knee Arthroplasty: A Report of 2 Cases

CASE

We report on 2 patients with atypical femur fractures that initially presented as painful total knee arthroplasties. There was a history of long-term bisphosphonate use in each case. Knee radiographs and laboratory studies were normal, and the patients were managed conservatively. Both subsequently sustained atypical femur fractures and underwent surgical stabilization.

CONCLUSIONS

Referred pain from a bisphosphonate-related femoral stress fracture can masquerade as pain about a total knee arthroplasty. This should be included in the differential diagnosis in at-risk patients because it can result in an atypical femoral shaft fracture above the prosthesis if not properly treated.

Bisphosphonate-related Femoral Shaft Fracture

The efficacy of using bisphosphonate therapy to treat osteoporotic patients is becoming more widely known, but the potential side effects may not be. While this class of drugs is generally safe, concerns have emerged regarding risks of atypical subtrochanteric fractures associated with long-term use. There have been a number of case reports discussing the association of patients on bisphosphonates who suffer a non-traumatic or a low-energy mechanism of injury atypical of subtrochanteric fractures. The purpose of this case report is to raise awareness of this potential side effect and provide increased clinical suspicion for this rare type of fracture.

[Atypical fracture of the femur related to prolonged bisphosphonate use. The importance of saying 'enough's enough']

Osteoporosis is a highly prevalent disease with important consequences. The most widely used drugs to control this disease are bisphosphonates but their prolonged use is associated with the risk of atypical fractures. We report the cases of two patients under bisphosphonate treatment with bilateral atypical femoral fractures. In one patient the fractures occurred simultaneously, unprovoked by trauma, and in the other, they occurred as delayed fractures after mild trauma. In both cases, the fractures were preceded by pain. The fractures were treated with intramedullary nailing and bisphosphonate withdrawal with good outcomes. Although bisphosphonates have demonstrated effectiveness in preventing frailty-related fractures, their prolonged use has paradoxically been associated with atypical fractures. These fractures are usually preceded by pain. Consequently, when faced with this clinical picture, physicians should request imaging studies that could show incomplete fractures that could benefit from prophylactic nailing before becoming complete fractures.