Osteosynthesis of an intertrochanteric fracture on osteopetrosis A case report

INTRODUCTION

Osteopetrosis is a rare hereditary disease that can be transmitted in an autosomal recessive or autosomal dominant.

CASE REPORT

Here, we report a case of trochanteric fracture in an 18-year-old boy with an anatomical plate. At the last follow-up, 24 months after surgery, the fracture had healed well, and the patient was not restricted in his activities.

DISCUSSION

Osteopetrosis is a rare bone disease that is mainly caused by osteoclast dysfunction. It results from a remodelling defect that leads to hypermineralization of the skeleton, resulting in bone fragility. Both surgical and nonsurgical management have advantages and disadvantages. Thus, open reduction and anatomic plate fixation remain effective management modalities for trochanteric fractures in osteopetrosis patients.

CONCLUSION

For our patient and as described in the literature, the complication rate decreases as some principles are respected with better consolidation of the osteoporotic fracture.

Reporting of Full-Length Femur Imaging to Detect Incomplete Atypical Femur Fractures: 2023 Official Positions of the International Society for Clinical Densitometry

Incomplete atypical femur fractures (iAFFs) are associated with the long-term use of anti-resorptive therapies. Although X-rays are typically used to screen for iAFFs, images from dual-energy X-ray absorptiometry (DXA) offer an alternate method for detecting iAFFs. Although a previous 2019 ISCD Official Position on this subject exists, our task force aimed to update the literature review and to propose recommendations on reporting findings related to iAFFs that may be observed on DXA images. The task force recommended that full-length femur imaging (FFI) from DXA can be used as a screening tool for iAFFs. The presence of focal lateral cortical thickening and transverse lucencies should be reported, if identified on the FFI. This task force proposed a classification system to determine the likelihood of an iAFF, based on radiographic features seen on the FFI. Lastly, the task force recommended that the clinical assessment of prodromal symptoms (pain) is not required for the assessment of FFI.

Association of atypical femoral fracture location and lower limb mechanical axis: a computed tomography-based finite element analysis

Atypical femoral fractures (AFFs) are categorized as low-energy fractures of the femoral shaft or subtrochanteric region. The use of computed tomography-based finite element analysis demonstrated that the femoral weakest point against tensile stress coincided with AFF location, which was determined by the lower limb axis and femoral bowing.

INTRODUCTION

This study aimed to assess the relationship between the femoral weakest point against tensile stress and the lower limb axis and geometry, including femoral bowing, using a computed tomography (CT)-based finite element analysis (FEA) model.

METHODS

We retrospectively reviewed 19 patients with AFFs and analyzed their CT images of the contralateral intact femur. We performed FEA to find the maximum principal stress (MPS) and maximal tensile stress loading area (femoral weakest point, FWP) of each patient and matched the FWP with the real location of AFF. We applied mechanical axes differently, as neutral, varus, and valgus, in the FEA model, when we analyzed the change in MPS and FWP based on lower limb alignment. We compared the degree of agreement between the real fracture location and FWP before and after knee mechanical axis adjustment.

RESULTS

The average participant age was 75.9 (range, 61-87) years, and all participants were women. In the 19 patients included, we observed 20 and 7 shaft and subtrochanteric AFFs, respectively. The average mechanical axis at the knee joint level was 22.6 mm (range, 0-70 mm) of the varus. All the patients showed an increasing trend of MPS and a distal movement of FWP when the mechanical axis of the knee was applied from the valgus to varus alignment. The root mean square errors between the FWP and real fracture location were 14.58% and 10.87% before and after adjustment, respectively, implying that the degree of agreement was better in patients who underwent mechanical adjustment.

CONCLUSION

The use of CT/FEA demonstrated that the FWP against tensile stress coincided with AFF location, which was determined by the lower limb axis and femoral bowing.

Bisphosphonates and the risk of atypical femur fractures

Bisphosphonates are effective in reducing hip and other fractures. However, concerns about atypical femur fractures (AFFs) have contributed to substantially decreased bisphosphonate use, and hip fracture rates may be increasing. Despite this impact, important uncertainties remain regarding AFF risks including the association between bisphosphonate use and other risk factors such as BMD, age, weight, and race. To address this evidence gap, a cohort study of 196,129 women ≥50 years of age in the Southern California Kaiser Permanente HMO women (with ≥1 bisphosphonate prescription) were studied; the primary outcome was radiographically-adjudicated AFF between 2007 and 2017. Risk factors including bisphosphonate use and race were obtained from electronic health records. Multivariable Cox models were used for analysis. Benefit-risk was modeled for 1-10 years of bisphosphonates to compare fractures prevented vs. AFFs associated. Among 196,129 women, 277 (0.1%) sustained AFFs. After multivariable adjustment, AFF risk increased with longer bisphosphonate duration: hazard ratio (HR) increased from HR = 8.9 (95%CI: 2.8,28) for 3-5 years to HR = 43.5 (13.7138.1) for >8 years. Hip BMD, surprisingly, was not associated with AFF risk. Other risk factors included Asian ancestry (HR = 4.8 (3.6, 6.6)), short stature, overweight, and glucocorticoid use. Bisphosphonate discontinuation was associated with rapid decrease in AFF risk. Decreases in osteoporotic and hip fractures risk during 1-10 years of bisphosphonates far outweighed the increase AFF risk in Caucasians, but less so in Asians. In Caucasians, after 3 years 149 hip fractures were prevented with 2 AFFs associated compared to 91 and 8 in Asians. The evidence for several potential mechanisms is summarized with femoral geometry being the most likely to explain AFF risk differences between Asians and Caucasians. The results from this new study add to the evidence base for AFF risk factors and will help inform clinical decision-making for individual patients about initiation and duration of bisphosphonate therapy and drug holidays.

Progression of atypical femur stress fracture after discontinuation of bisphosphonate therapy

Atypical femur fracture (AFF) is an uncommon complication of long-term bisphosphonate use, but the risk declines substantially after treatment cessation. We report a case of a 70-year-old woman with osteopenia treated with alendronate for 9 years who presented with right mid-thigh pain and radiographic findings of focal lateral cortical thickening in the right mid-femur and lateral cortex irregularity in the proximal-mid left femur. Alendronate was discontinued, but she remained on estrogen for menopausal symptoms. Four years later, a horizontal linear translucent defect was seen in the right mid-femur area of cortical hypertrophy, consistent with an incomplete AFF. The patient underwent prophylactic intramedullary rodding of the right femur and estrogen was discontinued. Three years later (7 years after initial presentation), the cortical irregularities in the left femur were more prominent and three small horizontal linear translucent defects were now evident, consistent with early incomplete atypical fracture development. The patient also suffered a wrist fracture. She was treated with teriparatide for 1.5 years with resolution of the translucent defects in the left but not the right femur, although abnormal thickening of the lateral cortex persisted in both femurs. Our case demonstrates incomplete atypical femur fracture progression in a patient with long-term bisphosphonate exposure, even after treatment cessation. These findings highlight the importance of follow-up for patients who develop diaphyseal femur stress fractures and the potential for early healing with anabolic therapy. This case also demonstrates the challenge in managing older patients with incomplete AFF at risk for progression to complete AFF and osteoporotic fracture.

Bilateral atypical fractures of the femur: Ten years AFTER ten years of bisphosphonate therapy

Background

Atypical femur fracture (AFF) is a clinically important complication of bisphosphonate (BP) use in the treatment of osteoporosis. The benefits of long-term BP therapy in preventing osteoporotic fractures have been shown to outweigh the risks of treatment. Discontinuation of BPs or "drug holidays" have been implemented as a strategy to reduce the risk of rare complications such as AFF.

Case report

We present the case of a 70-year-old postmenopausal woman who suffered bilateral AFF ten years after discontinuation of BP treatment. Management of this patient included fixation of the complete AFF with an intramedullary rod. A single dose of denosumab was administered prior to referral to endocrinology and seemed to contribute to callus formation. Denosumab was discontinued to prevent progression of the contralateral incomplete AFF. Teriparatide was indicated for the treatment of this patient's osteoporosis and also led to the resolution of the incomplete AFF.

Conclusion

Patients receiving long-term BP therapy should be periodically reevaluated in order to maximize the benefit and minimize the risk of treatment. Current research supports the implementation of drug holidays to decrease the risk of AFF; however, this case report confirms the need for continued monitoring after discontinuation of BP therapy. Additionally, our review of current literature highlights the need for more specific research regarding duration of BP treatment and drug holidays.

Outcome of revision surgery for bisphosphonate related subtrochanteric fracture non-union following failed intramedullary nailing

BACKGROUND

Bisphosphonates use is a recognised cause of atypical femur fractures. Intramedullary nailing is the first line of treatment for these fractures, but failure is a common problem due to altered biology, resulting in a non-union and a challenging problem.

PURPOSE

There is lack of evidence in the literature on revision surgery for the management of non-union after failed nailing in atypical femur fracture. We present our experience of treating this complex problem.

PATIENT AND METHODS

A retrospective review of all consecutive cases of revision surgery for non-union of bisphosphonate related subtrochanteric fractures was undertaken. All procedures were performed between 2012 and 2017 by a single surgeon. Revision surgery included removal of failed metalwork, resection of non-union, bone grafting and double plating with a lateral DCS plate and anterior locking compression plate.

RESULTS

Ten patients (9 females, 1 male) were included with a mean age of 71.5 years and mean BMI of 34 at the time of revision. All patients received previous Bisphosphonate treatment on average for 6.2 years. One patient was lost to follow up. Mean time for non-weight bearing (NWB) mobilization was 7 months and mean time for union was 14 months.

CONCLUSIONS

Fracture healing can be achieved with bone grafting and compression plating in all patients. However, a prolonged time to achieve union and a long follow-up duration should be expected.

Atypical periprosthetic femur fracture on an underestimated atypical femoral pattern. A case report

Case

Atypical fracture patterns, especially to the femur midshaft, have begun emerging since long-term bisphosphonate use was introduced. The same fracture pattern could arise around prosthetic hip implant, but the literature reports few cases regarding atypical periprosthetic femur fracture on previous total hip arthroplasty implant in patients on long-term bisphosphonate therapy. To our knowledge we report here the first case of atypical periprosthetic femur fracture arising after total hip arthroplasty implant on a previously identified but underestimated atypical femur pattern.

Conclusion

Surgeons should never underestimate an atypical femur pattern on x-rays and always relate groin and thigh pain to hip pathology before performing total hip arthroplasty.

Atypical femoral neck fracture after prolonged bisphosphonate therapy

Of the drugs developed to prevent and treat osteoporosis, bisphosphonate has played a very important role in preventing osteoporotic fractures. However, case reports describing atypical femoral fractures in patients using long-term bisphosphonates have emerged. The majority of atypical femur fractures occurs in the lateral aspect of the subtrochanteric or femur diaphysis, which is explained by accumulation of tensile stress in these areas. Although the superior cortex of the femur neck withstands maximum tensile stress, to our knowledge, there have been only two reports (three cases) of atypical femoral neck fracture. In addition, none of those case reports revealed detailed pathology related to suppressed bone turnover rate. We encountered an incomplete femoral neck fracture and diagnosed it as "atypical" on the basis of the patient's lack of trauma and medication history and pathological findings. For patients with groin pain, minimal or no trauma, and a history of long-term bisphosphonate use, an atypical femoral neck fracture should be considered.

Asian ethnicity is associated with atypical femur fractures in an Australian population study

Asian race, younger age, higher body mass index (BMI) and antiresorptive drugs have all been associated with atypical femur fractures (AFFs). This increased risk of AFF in Asians is important as by 2050, >50% of hip fractures globally will occur in Asia, with an increased demand for antiresorptive drugs being likely. It is also currently unclear whether AFF risk is increased in all Asian subgroups. We therefore aimed to identify the incidence of AFFs in an Australian tertiary hospital, the contribution of ethnic origin to AFF risk, and determine other clinical risk factors for AFF. From January 1, 2009 to December 31, 2017, 97 AFFs (82 complete and 15 incomplete) occurred in 71 individuals in the overall study population of 204,358. Patients with AFF were more likely to be female (88.7% vs 69.1%, p < 0.001) and younger [median (IQR): 74(52-92) years vs 83(75-88) years, p < 0.001] than the "typical" femur fracture group (n = 3330). The cumulative incidence rate of AFF was 4.2 per 100,000 person-years, far lower than for any ICD-10 AM coded "typical" femur fracture (202.9 per 100,000 person-years). Asians were 3.4 (95%CI, 2.1-5.6) times more likely to sustain an AFF than non-Asians, the highest incidence being in those from South East Asian countries (16.6 per 100,000 person years), suggesting differences in risk between Asian countries. In the nested case-control study, bisphosphonate use was an independent association with AFF development. We conclude Asian ethnicity is an important association with AFF in this large Australian cohort.

Atypical femur fracture incidence in women increases with duration of bisphosphonate exposure

In a northern California population of older women who were treated with oral bisphosphonate drugs, the incidence of atypical femur fracture, a rare complication of treatment, increased with longer duration of bisphosphonate exposure. These findings align with those previously reported in an independent southern California population.

INTRODUCTION

The age-adjusted incidence of atypical femur fracture (AFF) reported in southern California increased with bisphosphonate (BP) exposure, ranging up to 113 per 100,000 person-years for 8-10-year exposure. This study examines the incidence of AFF in a northern California population.

METHODS

Women age 45-89 years who initiated oral BP during 2002-2014 in Kaiser Permanente Northern California were followed for AFF outcome, defined by a primarily transverse diaphyseal femur fracture through both cortices, with focal periosteal/endosteal hypertrophy, minimal trauma, and minimal/no comminution. Total BP exposure was determined from dispensed prescriptions. The incidence of AFF, calculated for 2-year BP categories ranging from < 2 to > 10 years, was age-adjusted using the 2000 US Census.

RESULTS

Among 94,542 women, 107 experienced an AFF during or < 1 year after BP cessation (mean exposure 6.6 ± 3.0 years and total days' supply 5.7 ± 2.8 years at AFF). A strong relationship between AFF incidence and increasing BP exposure was seen, more than doubling for each 2-year category until 8-10 years. Among women with 2- to < 4-year BP, the crude and age-adjusted incidence was 18 and 9 per 100,000 person-years but increased over 2- and 5-fold for women with 4- to < 6- and 6- to < 8-year BP, respectively. For those receiving ≥ 8-year BP, the crude and age-adjusted incidence peaked at 196 and 112 per 100,000 person-years exposure.

CONCLUSION

Incidence of AFF increases markedly after 4-6 years of BP. These trends align with southern California and confirm a strong BP duration-related risk of this rare but serious event.

Executive Summary of the 2019 ISCD Position Development Conference on Monitoring Treatment, DXA Cross-calibration and Least Significant Change, Spinal Cord Injury, Peri-prosthetic and Orthopedic Bone Health, Transgender Medicine, and Pediatrics

To answer important questions in the fields of monitoring with densitometry, dual-energy X-ray absorptiometry machine cross-calibration, monitoring, spinal cord injury, periprosthetic and orthopedic bone health, transgender medicine, and pediatric bone health, the International Society for Clinical Densitometry (ISCD) held a Position Development Conference from March 20 to 23, 2019. Potential topics requiring guidance were solicited from ISCD members in 2017. Following that, a steering committee selected, prioritized, and grouped topics into Task Forces. Chairs for each Task Force were appointed and the members were co-opted from suggestions by the Steering Committee and Task Force Chairs. The Task Forces developed key questions, performed literature searches, and came up with proposed initial positions with substantiating draft publications, with support from the Steering Committee. An invited Panel of Experts first performed a review of draft positions using a modified RAND Appropriateness Method with voting for appropriateness. Draft positions deemed appropriate were further edited and presented at the Position Development Conference meeting in an open forum. A second round of voting occurred after discussions to approve or reject the positions. Finally, a face-to-face closed session with experts and Task Force Chairs, and subsequent electronic follow-up resulted in 34 Official Positions of the ISCD approved by the ISCD Board on May 28, 2019. The Official Positions and the supporting evidence were submitted for publication on July 1, 2019. This paper provides a summary of the all the ISCD Adult and Pediatric Official Positions, with the new 2019 positions highlighted in bold.

Detection of Atypical Femur Fractures

The 2019 International Society for Clinical Densitometry (ISCD) Position Development Conference Task Force for monitoring with dual-energy X-ray absorptiometry (DXA) identified detection of atypical femur fractures (AFFs) as an important topic and established this working group to answer key questions in this area. The authors conducted a systematic review of the literature and deliberated on proposed ISCD positions, which were then reviewed by an external expert panel and vetted at the 2019 ISCD Position Development Conference in Kuala Lumpur on March 23, 2019. This paper summarizes the final ISCD positions and the rationale for supporting these positions. Default-length femur imaging or extended-length femur imaging as well as full-length femur imaging (FFI), both single-energy and dual-energy scans, by DXA can detect abnormalities in the spectrum of AFF. It is important to visually inspect all DXA scans of the hip and femur, and report on findings of focal periosteal and endosteal thickening at the lateral cortex (grade: Good, A, W). FFI is the preferred DXA scan mode for detecting abnormalities in the spectrum of AFF. The FFI report should state the absence or presence of abnormalities in the spectrum of AFF. If focal thickening is present on the lateral cortex, the report should state whether a lucent line is seen (grade: Fair, C, W). The ISCD recommends considering the use of bilateral FFI in patients who are currently or have been in the past year on potent antiresorptive therapy (ie, oral or intravenous bisphosphonate or subcutaneous denosumab therapy) for a cumulative period of 3 or more years, especially those on long-term glucocorticoid therapy (grade: Fair, B, W). More research is needed to determine the role of repeat testing and the optimal time interval for follow-up DXA scans, whether an automated measuring tool would perform better than visual inspection, whether FFI would change patient management and outcomes, and the cost-effectiveness of FFI.

Atypical femoral fractures from bisphosphonate in cancer patients - Review

Bisphosphonates are commonly used in patients with metastatic bone disease to prevent skeletal related events. Atypical femur fracture is a known complication of long-term bisphosphonate use but the incidence in cancer patients and pathogenesis are not well known. Several mechanisms of pathogenesis have been proposed including altered angiogenesis, altered bone mechanical properties, micro damage and bone remodeling suppression. Atypical femur fractures are atraumatic or minimally traumatic fractures in the sub trochanteric region or the femoral shaft. Awareness of atypical femur fractures is critical to diagnose and treat them in a timely manner. There is a paucity of data regarding the management of atypical femur fracture in patients with malignancy. Management options of atypical femur fractures include stopping bisphosphonates, initiating calcium/vitamin D supplementation and either surgery with internal fixation or conservative management. In the future, it will be important to explore the effect of continuous vs. intermittent exposure, cumulative dose and length of exposure on the incidence of this complication. Herein, we review the epidemiology, risk factors, management options and proposed mechanisms of pathogenesis of atypical femur fractures.

Radiological criteria for atypical features of femur fractures: what we can learn when applied in a clinical study setting

The paper focuses on the identification of atypical fractures (AFFs). This paper examines the concordance between objective classification and expert subjective review. We believe the paper adds critical information about how to apply the American Society of Bone and Mineral Research (ASBMR) criteria to diagnose AFFs and is of high interest to the field.

INTRODUCTION

Assess American Society of Bone and Mineral Research (ASBMR) criteria for identifying atypical femoral fractures (AFFs).

METHODS

Two orthopedic surgeons independently evaluated radiographs of 372 fractures, applying ASBMR criteria. We assessed ease of applying ASBMR criteria and whether criteria-based assessment matched qualitative expert assessment.

RESULTS

There was up to 27% uncertainty about how to classify specific features. 84% of films were classified similarly for the presence of AFF according to ASBMR criteria; agreement increased to 94% after consensus meeting. Of 37 fractures categorized as AFFs based on ASBMR criteria, 23 (62.2%) were considered AFFs according to expert assessment (not relying on criteria). Only one (0.5%) femoral shaft fracture that did not meet ASBMR criteria was considered an AFF per expert assessment. The number of major ASBMR features present (four vs five) and whether there was periosteal or endosteal thickening ("beaking" or "flaring") played major roles in the discrepancies between ASBMR criteria-based and expert-based determinations.

CONCLUSIONS

ASBMR AFF criteria were useful for reviewers but several features were difficult to interpret. Expert assessments did not agree with the ASBMR classification in almost one-third of cases, but rarely identified an AFF when a femoral shaft fracture did not meet ASBMR AFF criteria. Experts identified lateral cortical transverse fracture line and associated new-bone formation along with no or minimal comminution as crucial features necessary for the definition of atypical femoral fractures.

Bisphosphonates Use and Risk of Subtrochanteric and Diaphyseal Femur Fractures in Korea: Results from the National Claim Registry

Although Asian with bisphosphonate has been considered to have higher risk of subtrochanteric and diaphyseal femur (ST/DF) fractures, the occurrence of those fractures has been still unclear in Asia. The purpose of this study was to investigate the incidence rate of ST/DF fractures among bisphosphonate users from nationwide database in South Korea. Using national health insurance claim database, we only included the bisphosphonate users who took bisphosphonate for the first time in 2008 and evaluated the incidence rate of ST/DF fracture from 2008 to 2013. Non-user controls were matched to bisphosphonate users by propensity score matching with age and gender. Cox regression models were used to calculate hazard ratios of ST/DF fracture with and without adjustment for comorbidity. A total of 682 ST/DF fractures were observed among 348,311 bisphosphonate users. The incidence rate of ST/DF fracture among bisphosphonate users (37.75/100,000 person years, 95% CI 35.02-40.70) was higher compared with non-users (24.41/100,000 person years, 95% CI 22.31-26.71). The risk of ST/DF fracture was greater in bisphosphonate users compared with non-users (hazard ratio 1.541, 1.370-1.734; p < 0.001). The incidence rate of ST/DF fracture after bisphosphonate use could be determined in Korean patients, which can provide basal information for further studies on risk and benefit of continuing bisphosphonate.

Current Understanding of Epidemiology, Pathophysiology, and Management of Atypical Femur Fractures

PURPOSE OF REVIEW

To summarize reports published since the 2013 American Society of Bone and Mineral Research Task Force Report on atypical femoral fractures (AFF).

RECENT FINDINGS

The absolute incidence of AFFs remains low. AFFs are primarily associated with prolonged bisphosphonate (BP) exposure, but have also been reported in unexposed patients and those receiving denosumab for osteoporosis and metastatic bone disease. Asians may be more susceptible to AFFs. Lateral femoral bowing and varus hip geometry, which increase loading forces on the lateral femoral cortex, may increase AFF risk. Altered bone material properties associated with BP therapy may predispose to AFFs by permitting initiation and increasing propagation of micro-cracks. Relevant genetic mutations have been reported in patients with AFFs. Single X-ray absorptiometry femur scans permit early detection of incomplete and/or asymptomatic AFFs. Orthopedists recommend intramedullary rods for complete AFFs and for incomplete, radiologically advanced AFFs associated with pain and/or marrow edema on MRI. Teriparatide may advance AFF healing but few data support its efficacy. Greater understanding of biological and genetic predisposition to AFF may allow characterization of individual risk prior to initiating osteoporosis therapy and help allay fear in those at low risk for this complication, which remains rare in comparison to the osteoporotic fractures prevented by antiresorptive therapy.

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.

Teriparatide for treatment of patients with bisphosphonate-associated atypical fracture of the femur

The Fracture Improvement with Teriparatide (Fix-IT) study randomized 13 women with an atypical femur fracture to immediate vs delayed teriparatide therapy; all were followed for 12 months. Results suggested a trend for superior healing and lesser bone mineral density declines in the immediate vs delayed group with no differences in adverse events.

PURPOSE

Little clinical data are available on the use of teriparatide for the treatment of bisphosphonate-associated atypical femur fractures (AFF). The goal of the Fix-IT study was to determine if immediate therapy with teriparatide was superior for fracture healing after an AFF compared to a 6-month delay in teriparatide therapy.

METHODS

This randomized pilot clinical trial included 13 women with an AFF who were randomized to immediate teriparatide vs a delay of 6 months. All were followed for 12 months on teriparatide. The primary outcomes included individual and composite measures of radiologic bone healing (scored 1 point [no healing] to 4 points [complete healing]) at 6 and 12 months. Secondary outcomes included bone mineral density of the unfractured contralateral hip, spine, 1/3 distal radius, and adverse events.

RESULTS

We found there was a trend for superior healing with the composite score (12.6 vs 11.2 at 6 months and 15.4 vs 13.2 at 12 months), and lesser bone mineral density declines at the 1/3 distal radius (12-month change - 1.9 vs - 6.1%) in the immediate vs the delayed group. There were no differences in adverse events. There was one implant failure in the delayed group.

CONCLUSIONS

There is a preliminary signal for greater improvements with immediate teriparatide therapy vs delayed therapy. However, because an AFF is a rare event, and only a small number of patients were included, the results must be interpreted with caution.

Factors affecting fracture location in atypical femoral fractures: A cross-sectional study with 147 patients

INTRODUCTION

Many studies have tried to determine the characteristics of atypical femoral fractures (AFFs) through age-, sex-, and ethnicity-matched comparison with non-AFFs. However, we hypothesized that diaphyseal AFFs would have characteristics different from those of subtrochanteric AFFs. The aim of this study was to evaluate the clinical features of diaphyseal/subtrochanteric AFFs and determine the factors related to fracture location.

PATIENTS AND METHODS

One hundred forty-seven patients with AFF were enrolled, 114 patients (78%) had a history of bisphosphonate use. Forty-nine patients (33%) had bilateral lesion, and 35% of patients had thigh pain. Patients were divided into two groups according to fracture location: 52 patients (35.4%) with subtrochanteric AFF and 95 patients (64.6%) with diaphyseal AFF. The patient demographics and fracture characteristics of the two groups were compared. Multivariate logistic regression analysis was used to adjust for variables related to fracture location.

RESULTS

The patients in the diaphyseal AFFs group were older and had lower BMI, lower BMD, and larger lateral and anterior bowing. Multivariate analysis revealed that age greater than 65 years and low BMD were related with diaphyseal location. With greater lateral bowing angle, the AFF location was moved from the subtrochanteric area to the diaphyseal area.

CONCLUSION

This study demonstrated that patients with diaphyseal AFFs had different characteristics compared with those with subtrochanteric AFFs.

Bone Structure and Turnover Status in Postmenopausal Women with Atypical Femur Fracture After Prolonged Bisphosphonate Therapy

Atypical femur fracture (AFF), a serious complication of long-term bisphosphonate therapy, is usually preceded by an incomplete fracture appearing on the lateral femur. AFF is most likely the result of severely suppressed bone turnover (SSBT). However, the differences in bone structure and turnover between patients with incomplete and complete AFF remain unknown. We examined trans-iliac bone biopsies from 12 white postmenopausal women with AFF (incomplete = 5; complete = 7) on BP therapy of >5 years and 43 healthy white premenopausal women. Histomorphometric measurements were performed separately in cancellous, intracortical and endosteal envelopes. Of the 43 histomorphometric measurements on 3 difference bone surfaces (cancellous, intracortical and endosteal), only 2 bone resorption variables (Oc.S/BS and Oc.S/NOS) on the endosteal surface were significantly lower in patients with complete AFF than those with incomplete AFF. Compared to healthy premenopausal women, the trabecular bone volume, thickness and number were all significantly lower in patients with AFF. The dynamic bone formation variables in patients with AFF were significantly reduced on all bone surfaces. The likelihood of a biopsy with no tetracycline labeling was significantly higher in AFF patients than in healthy premenopausal women. Based on these results, we conclude that there are no significant differences in bone turnover between patients with incomplete and complete AFF, suggesting that the suppression of bone turnover had already existed in the femur with incomplete AFF. Compared to healthy premenopausal women, bone turnover is similarly suppressed in patients with either type of AFF.

Bilateral atypical femur fractures without bisphosphonate exposure

Atypical femur fractures have common radiographic features that set them apart from more typical higher-energy subtrochanteric femur fractures. They are noncomminuted, transverse fractures with medial spiking of the femoral cortex and increased lateral cortical thickness. These fractures have been associated in the literature with the use of bisphosphonate medications. This case describes bilateral atypical femur fractures in a patient with a medical history devoid of bisphosphonate use. We present his history, co-morbidities, and subsequent treatment. From this case, we call attention to bisphosphonate use as not the only cause of subtrochanteric femur fractures with atypical features and highlight that some patients may sustain these injuries even bilaterally without use of the medications. In addition, it is important to identify this fracture type and obtain imaging of the contralateral femur to facilitate prophylactic treatment if needed.

Atypical femur fracture in an adolescent boy treated with bisphosphonates for X-linked osteoporosis based on PLS3 mutation

Long-term use of bisphosphonates has raised concerns about the association with Atypical Femur Fractures (AFFs) that have been reported mainly in postmenopausal women. We report a case of an 18-year-old patient with juvenile osteoporosis based on X-linked osteoporosis due to a PLS3 mutation who developed a low trauma femoral fracture after seven years of intravenous and two years of oral bisphosphonate use, fulfilling the revised ASBMR diagnostic criteria of an AFF. The occurrence of AFFs has not been described previously in children or adolescents. The underlying monogenetic bone disease in our case strengthens the possibility of a genetic predisposition at least in some cases of AFF. We cannot exclude that a transverse fracture of the tibia that also occurred after a minor trauma at age 16 might be part of the same spectrum of atypical fractures related to the use of bisphosphonates. In retrospect our patient experienced prodromal pain prior to both the tibia and the femur fracture. Case reports of atypical fractures in children with a monogenetic bone disease such as Osteogenesis Imperfecta (OI) or juvenile osteoporosis are important to consider in the discussion about optimal duration of bisphosphonate therapy in growing children. In conclusion, this case report 1) highlights that AFFs also occur in adolescents treated with bisphosphonates during childhood and pain in weight-bearing bones can point towards this diagnosis 2) supports other reports suggesting that low trauma fractures of other long bones besides the femur may be related to long-term use of bisphosphonates 3) strengthens the concept of an underlying genetic predisposition in some cases of AFF, now for the first time reported in X-linked osteoporosis due to a mutation in PLS3 and 4) should be considered in decisions about the duration of bisphosphonate therapy in children with congenital bone disorders.

Clinical features of atypical femur fracture

Objectives

We aim to elucidate the clinical outcomes of bisphosphonate-associated atypical femoral fracture and the clinical results depending on the bisphosphonate therapy period.

Methods

Twenty cases involving 15 patients who had been diagnosed with atypical femoral facture between 2004 and 2014 and who had been followed up for at least 12 months were retrospectively analyzed. The control group was composed of 15 typical femoral facture patients. We used plain radiography and physical examinations to determine the period of time required for fracture healing as well as complication occurrence. We investigated the bisphosphonate administration status and duration and the names of its components, bilateral fracture occurrence status, the period of time required for bone union, and reoperation or bone graft status due to nonunion.

Results

Revision surgery involving a bone graft was performed due to nonunion in 1 out of 15 cases. Except in one revision case, the duration of the union was 11.9 months on average in 14 cases of atypical fracture patients, and 4.3 months on average in the control group. This difference was statistically significant (p < 0.05). The bisphosphonate administration duration was positively correlated with the union period (p < 0.05). In contrast, there was no statistically significant correlation between the bisphosphonate administration duration and the incidence of bilateral atypical fractures (p > 0.05).

Conclusions

Atypical femoral fractures required more time for bone union than typical ones and prolonged bisphosphonate administration led to a longer period of time required for bone union.

Surgical tips of intramedullary nailing in severely bowed femurs in atypical femur fractures: Simulation with 3D printed model

INTRODUCTION

The surgical management of atypical femoral fractures (AFFs) is complex in cases with severe bowing of the femur, being associated with a high rate of failure. Our first aim was to use preoperative templating and 3D printed model characterise the technical difficulties associated with use of current commercially available intramedullary nail (IMN) systems for the management of AFFs with severe bowing. Our second aim was to use outcomes of our 3D printing analysis to define technical criteria to overcome these problems.

MATERIAL AND METHODS

The modelled femur with 3D printing had an anterior bowing curvature radius of 772mm and an angle of lateral bowing of 15.4°. Nine commercially available IMN systems were evaluated in terms of position of the nail within the medullary canal, occurrence of perforation of femoral cortex by the distal tip of the nail, and location of the site of perforation relative to the knee joint. The following IMN systems were evaluated: unreamed femoral nail (UFN), cannulated femoral nail (CFN), Sirus nail, right and left expert Asian femoral nail (A2FN), right and left Zimmer Natural Nail (ZNN), proximal femoral nail anti-rotation (PFNA), and Zimmer Cephalomedullary Nail (CMN).

RESULTS

Along the sagittal plane, the UFN, CFN and Sirus systems were acceptably contained within the medullary canal, as well as the "opposite side" A2FN and ZNN. Only the Sirus IMN system was contained along the coronal plane. The distal part of the all other IMN systems perforated the anterior cortex of the femur, at distances ranging between 2.8 and 11.7cm above the distal end of the femoral condyles. Using simulated fracture reduction in the 3D printed model, none of the 9 IMN systems provided acceptable anatomical reduction of the fracture. A residual gap in fragment position and translation was provided by the "opposite side" ZNN, followed by the UFN and Sirus systems.

CONCLUSION

Commercially available IMN systems showed mismatch with severely bowed femurs. Our simulation supports that fit of these systems can be improved using an IMN system with a small radius of curvature and diameter, and by applying specific operative procedures.

The advantages of tomosynthesis for evaluating bisphosphonate-related atypical femur fractures compared to radiography

OBJECTIVE

To investigate the advantages of using tomosynthesis (TS) compared to radiographs in the detection, characterization, and follow-up of bisphosphonate-related atypical femur fractures (BP-AFF).

SUBJECTS AND METHODS

Eight patients were identified retrospectively who underwent TS for radiographic findings suspicious for BP-AFF. Two radiologists independently interpreted 15 radiographs and 16 TS examinations, indicating the presence or absence of the following: (1) cortical "beaking" on radiographs, (2) radiolucent fracture line on radiographs, and (3) fracture lucency on TS corresponding to the site of radiographic abnormality. Radiation dose data were calculated for radiographs and TS using Monte Carlo analysis.

RESULTS

There was agreement on 100 % of radiographs regarding the presence or absence of a cortical beak. Regarding the presence or absence of a fracture lucency, there was agreement on 100 % of TS examinations (Kappa = 1.0) and 73 % of radiographs (Kappa = 0.40 ± 0.24). For the 46 % of radiographs in which one or both radiologists did not visualize a fracture line, there was 100 % agreement for the presence of a fracture line on the corresponding TS. The interobserver agreement for fracture line detection was significantly higher for TS than for radiographs (p = 0.012). The effective radiation dose using TS was approximately 96 % lower compared to radiography.

CONCLUSION

TS outperformed radiographs in the detection and characterization of BP-AFF. TS may also have advantages over radiography for BP-AFF follow-up through its unique ability to visualize fracture healing with lower effective radiation doses to the patient.

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.

Assessment of femur geometrical parameters using EOS™ imaging technology in patients with atypical femur fractures; preliminary results

Atypical femur fractures (AFF) arise in the subtrochanteric and diaphyseal regions. Because of this unique distribution, we hypothesized that patients with AFF demonstrate specific geometrical variations of their lower limb whereby baseline tensile forces applied to the lateral cortex are higher and might favor the appearance of these rare stress fractures, when exposed to bisphosphonates. Using the low irradiation 2D-3D X-ray scanner EOS™ imaging technology we aimed to characterize and compare femur geometric parameters between women who sustained bisphosphonate-associated AFF and those who had experienced similar duration of exposure to bisphosphonates but did not sustain fractures. Conditional logistic regression models were constructed to estimate the association between selected geometric parameters and the occurrence of AFF. We identified 16 Caucasian women with AFF and recruited 16 ethnicity-, sex-, age-, height- and cumulative bisphosphonate exposure-matched controls from local osteoporosis clinics. Compared to controls, those with AFF had more lateral femur bowing (-3.2° SD [3.4] versus -0.8° SD [1.9] p=0.02). In regression analysis, lateral femur bowing was associated with the risk of AFF (aOR 1.54; 95% CI 1.04-2.28, p=0.03). Women who sustained a subtrochanteric AFF demonstrated a lesser femoral neck shaft angle (varus geometry) than those with a fracture at a diaphyseal site (121.9 [3.6]° versus 127.6 [7.2]°, p=0.07), whereas femur bowing was more prominent in those with a diaphyseal fracture compared to those with a subtrochanteric fracture (-4.3 [3.2]° versus -0.9 [2.7]°, p=0.07). Our analyses support that subjects with AFF exhibit femoral geometry parameters that result in higher tensile mechanical load on the lateral femur. This may play a critical role in the pathogenesis of AFF and requires further evaluation in a larger size population.

Fractures on bisphosphonates in osteoporosis pseudoglioma syndrome (OPPG): pQCT shows poor bone density and structure

Osteoporosis pseudoglioma syndrome (OPPG) is a rare autosomal recessive disorder of childhood osteoporosis and blindness due to inactivating mutations in LDL receptor-like protein 5 (LRP5). We and others have reported improvement in areal bone mineral density (aBMD) by DXA in OPPG on short term bisphosphonates. Long-term data on bisphosphonate use in OPPG and measures of volumetric BMD (vBMD) and cortical structure are not available. In addition, no long-term DXA data on untreated OPPG is available. The aims of this study were to: (1) record low trauma fractures and longitudinal aBMD by DXA in 5 OPPG patients on chronic bisphosphonate treatment, and in 4 OPPG patients never treated (2) to perform tibia peripheral quantitative CT (pQCT) to evaluate volumetric bone mineral density (vBMD), cortical structure and calf muscle area in 6 OPPG patients and 14 unaffected first degree family members. pQCT results were converted to sex-specific Z-scores for age and adjusted for tibia length based on data in >700 reference participants. We observed 4 fractures (3 femoral shafts) in 3 OPPG patients while on bisphosphonates, after each achieved significant improvement in aBMD. OPPG participants had significantly lower mean trabecular vBMD (-1.51 vs. 0.17, p = 0.002), cortical area (-2.36 vs. 0.37; p < 0.001) and periosteal circumference (-1.86 vs. -0.31, p = 0.001) Z-scores, compared with unaffected participants and had a trend toward lower muscle area Z-score (-0.69 vs. 0.47, p = 0.12). These data demonstrate substantial bone fragility despite improvements in aBMD. The pQCT data provide insight into the fragility with substantial deficits in trabecular vBMD and cortical dimensions, consistent with OPPG effects of bone formation. Treatment that improves bone quality is needed to reduce fractures in OPPG.

Symptomatic atypical femoral fractures are related to underlying hip geometry

The benefits of bisphosphonates are well documented, but prolonged use has been associated with atypical femur fractures. Radiographic markers for fracture predisposition could potentially aid in safer medication use. In this case-control designed study, we compared hip radiographic parameters and the demographic characteristics of chronic bisphosphonate users who sustained an atypical femoral fracture with a group of chronic bisphosphonate users who did not sustain an atypical femur fracture and also a group who sustained an intertrochanteric hip fracture. Radiographic parameters included were neck-shaft angle (NSA), hip-axis length (HAL) and center-edge angle (CE). Multivariate regression was used to evaluate the relationship between radiographic measures and femur fracture. Receiver-operating characteristic analysis determined cut-off points for neck-shaft angle and risk of atypical femur fracture. Ultimately, pre-fracture radiographs of 53 bisphosphonate users who developed atypical fracture were compared with 43 asymptomatic chronic bisphosphonate users and 64 intertrochanteric fracture patients. Duration of bisphosphonate use did not statistically differ between users sustaining atypical fracture and those without fracture (7.9 [±3.5] vs. 7.7 [±3.3] years, p=0.7). Bisphosphonate users who fractured had acute/varus pre-fracture neck-shaft angles (p<0.001), shorter hip-axis length (p<0.01), and narrower center-edge angles (p<0.01). Regression analysis revealed associations between neck-shaft angle (OR=0.89 [95% CI=0.81-0.97; p=0.01), center edge angle (OR=0.89 [95% CI=0.80-0.99]; p=0.03), and BMI (OR=1.15 [95% CI=1.02-1.31; p=0.03) with fracture development. ROC curve analysis (AUC=0.67 [95% CI=0.56-0.79]) determined that a cut-off point for neck-shaft angle <128.3° yielded 69% sensitivity and 63% specificity for development of atypical femoral fracture. Ultimately, an acute/varus angle of the femoral neck, high BMI, and narrow center-edge angle were associated with development of atypical femur fracture in long-term bisphosphonate users. Patients on long-term bisphosphonates should be regularly radiographically evaluated in order to assess for potential risk of atypical fracture.

Absence of femoral cortical thickening in long-term bisphosphonate users: implications for atypical femur fractures

The radiographs of patients on long term bisphosphonates with atypical femur fractures demonstrate markedly thick cortices at the site of the fracture. We conducted a prospective clinical study to determine if cortical thickening is increased in long term bisphosphonate users. We recruited 43 patients who had taken bisphosphonates for more than 5 years. A group of 45 healthy volunteers and 12 patients recently diagnosed with osteoporosis served as controls. We measured the cortical thickening as the ratio of femoral cortical thickness to diameter of the femur, and looked for cortical beaking. No difference in the cortical thickness ratio was observed between long term bisphosphonate users and osteoporotic controls (0.53 vs. 0.54, p=0.659). No cases of cortical beaking were seen and no increase in thigh pain was observed. The power of the study was 95% to detect a 10% difference in cortical thickness ratio. We conclude that long term bisphosphonate use does not produce a generalized increase in subtrochanteric femoral cortical thickening in the majority of patients.

Glucocorticoid-induced osteoporosis: an update on effects and management

Glucocorticoids remain a cornerstone of guideline-based management of persistent asthma and allergic diseases. Glucocorticoid-induced osteoporosis (GIO) is the most common iatrogenic cause of secondary osteoporosis and an issue of concern for physicians treating patients with inhaled or oral glucocorticoids either continuously or intermittently. Patients with GIO experience fragility fractures at better dual-energy x-ray absorptiometry T-scores than those with postmenopausal or age-related osteoporosis. This might be explained, at least in part, by the effects of glucocorticoids not only on osteoclasts but also on osteoblasts and osteocytes. Effective options to detect and manage GIO exist, and a management algorithm has been published by the American College of Rheumatology to provide treatment guidance for clinicians. This review will summarize GIO epidemiology and pathophysiology and assess the role of inhaled and oral glucocorticoids in asthmatic adults and children, with particular emphasis on the effect of such therapies on bone health. Lastly, we will review the American College of Rheumatology GIO guidelines and discuss diagnostic and therapeutic strategies to mitigate the risk of GIO and fragility fractures.