Atypical Subtrochanteric Femoral Fractures Research Articles

The Role of Lower-Limb Geometry in the Pathophysiology of Atypical Femoral Fracture.

The etiology of atypical femoral fracture (AFF) is likely multifactorial. In this review, we examined the recent literature investigating the role of lower-limb geometry in the pathophysiology of AFF. Increased femoral bowing was associated with prevalent AFF and a greater likelihood of a diaphyseal versus a subtrochanteric AFF location. Femoral neck geometry or hip alignment may also be related to AFF, but findings remain equivocal. Differences in femoral geometry may, in part, be responsible for the high rate of AFF in Asian compared with Caucasian populations. Finally, simulation studies suggest that lower-limb geometry influences AFF risk via its effects on mechanical strain of the lateral femoral cortex. Femoral geometry, and bowing in particular, is related to prevalent AFF, but more prospective investigation is needed to determine whether measurements of geometry can be used for clinical risk stratification.

Atypical subtrochanteric femur fracture following bisphosphonates: A grey area of diagnosis and management

Background and objective: Osteoporosis is a common orthopaedic problem of the geriatric population. Bisphosphonates have been effectively used to control osteoporosis and improve the bone strength. Bisphosphonates has particularly been used in glucocorticoid induced osteoporosis. However, there are emerging concerns over the risk of atypical femoral pathological fractures consequent to prolonged use of BPN therapy. This study was designed to report the diagnosis and treatment of atypical subtrochanteric femur fractures after bisphosphonate treatment. Subject and methods: We report a rare case of atypical femur fracture in a 70-year-old female patient who has been taking bisphosphonates for glucocorticoid-induced osteoporosis for 5 years. She suffered a subtrochanteric fracture after tripping on the doorstep. The fracture was fixed using a titanium proximal femur nail. The patient was followed up by X-ray examination 1 year after operation. This study was conducted in accordance with the Declaration of Helsinki and approved by the Institutional Review Board of Jagadguru Sri Shivarathreeshwara Hospital, India. Written informed consent was obtained from the patient. Results: The postoperative period was uneventful, and the patient recovered well. The patient was independently ambulatory with good function of her left hip. Conclusion: Atypical femoral fractures are defined clearly by the American Society of Bone and Mineral Research (ASBMR) criteria. Many reports in the literature have reported atypical femoral fractures after bisphosphonates therapy but do not meet the ASBMR criteria. The risk ratio of atypical femoral fractures after bisphosphonates use is high. Regular monitoring and screening of patients on bisphosphonates therapy by radiographs allow us to diagnose these fractures early and treat them successfully.

Failure of Intramedullary Nailing for Subtrochanteric Atypical Femoral Fractures Caused by Endosteal Cortical Thickening

Failure of Intramedullary Nailing for Subtrochanteric Atypical Femoral Fractures Caused by Endosteal Cortical Thickening

Lessons Learned from Long-Term Management of Hip Fracture in Patients with Osteopetrosis: A Report of Nine Hips in Five Patients.

BackgroundTreating patients with osteopetrosis is very challenging even in very skilled surgeons with many experiences. We present an account of 5 patients treated for hip fracture related problems occurring throughout their life due to this disease. Difficulties encountered during their treatment prompted us to present some general management principles.MethodsFrom January 2003 to December 2016, 5 patients with osteopetrosis (9 hips; 3 men, 2 women), who underwent operative or conservative treatment were retrospectively reviewed. We evaluated their clinical features and rate of union, malunion and post-operative infection.ResultsFour of 5 patients (80%) suffered bilateral fracture, and 8 of 9 fractures (89%) are transverse and occurred at subtrochanteric area resulted from minor trauma. Among 9 hips, surgery was performed in seven hips. Nonunion were found in 3 hips (33%), malunion in 1 hip (11%) and oteomyelitis was developed in 2 hips (22%) at a median of 8.1 years.ConclusionsClinical features of hip fracture in osteopetrosis are very similar to atypical subtrochanteric femoral fractures. Patients should be informed of the possibilities of several anticipated complications including the risk of nonunion and infection after surgery.

Hip Fracture Nonunions: Diagnosis, Treatment, and Special Considerations in Elderly Patients.

In the United States, more than 300,000 hip fractures occur annually in the elderly population with associated significant morbidity and mortality. Both intracapsular and extracapsular hip fractures have inherent treatment challenges and therefore are at risk of nonunion complications. A systematic assessment including radiographic, metabolic, and infectious evaluations should be completed for all patients suspected of nonunion. Failed internal fixation of intracapsular hip fractures is typically treated with arthroplasty, while extracapsular proximal femur nonunions may be amenable to revision internal fixation or arthroplasty. While not a classic hip fracture, bisphosphate associated subtrochanteric femur fractures affect a similar patient population and are historically difficult to treat. Atypical subtrochanteric femur fractures are at increased risk of nonunion given the altered biologic environment secondary to bisphosphonate use; therefore adjuvant therapies may be beneficial in setting of revision fixation. Having a thorough understanding of nonunion risks, recognition, evaluation, and treatment is necessary for appropriate patient care.

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

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. 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. 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. 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. 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 III, economic and decision analyses.

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 5years, 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 2months, nine of which (42.9%) achieved radiological union with a mean time to union of 297days. 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.

Location of atypical femoral fracture can be determined by tensile stress distribution influenced by femoral bowing and neck-shaft angle: a CT-based nonlinear finite element analysis model for the assessment of femoral shaft loading stress

IntroductionLoading stress due to individual variations in femoral morphology is thought to be strongly associated with the pathogenesis of atypical femoral fracture (AFF). In Japan, studies on AFF regarding pathogenesis in the mid-shaft are well-documented and a key factor in the injury is thought to be femoral shaft bowing deformity. Thus, we developed a CT-based finite element analysis (CT/FEA) model to assess distribution of loading stress in the femoral shaft. Patients and MethodsA multicenter prospective study was performed at 12 hospitals in Japan from August 2015 to February 2017. We assembled three study groups—the mid-shaft AFF group (n=12), the subtrochanteric AFF group (n=10), and the control group (n=11)—and analyzed femoral morphology and loading stress in the femoral shaft by nonlinear CT/FEA. ResultsFemoral bowing in the mid-shaft AFF group was significantly greater (lateral bowing, p<0.0001; anterior bowing, p<0.01). Femoral neck-shaft angle in the subtrochanteric AFF group was significantly smaller (p<0.001). On CT/FEA, both the mid-shaft and subtrochanteric AFF group showed maximum tensile stress located adjacent to the fracture site. Quantitatively, there was a correlation between femoral bowing and the ratio of tensile stress, which was calculated between the mid-shaft and subtrochanteric region (lateral bowing, r=0.6373, p<0.0001; anterior bowing, r=−0.5825, p<0.001). ConclusionsCT/FEA demonstrated that tensile stress by loading stress can cause AFF. The location of AFF injury could be determined by individual stress distribution influenced by femoral bowing and neck-shaft angle.

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

IntroductionMany 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 methodsOne 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. ResultsThe 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. ConclusionThis study demonstrated that patients with diaphyseal AFFs had different characteristics compared with those with subtrochanteric AFFs.

Healing of Atypical Subtrochanteric Femur Fractures After Cephalomedullary Nailing: Which Factors Predict Union?

The purpose of this study was to determine the healing rate and time to union of atypical subtrochanteric fractures treated with cephalomedullary nailing. Retrospective review, descriptive, and analytic study. Six level 1 trauma centers. The study included 42 patients with 48 displaced, atypical, bisphosphonate-associated subtrochanteric femur fractures who underwent surgical intervention. Cephalomedullary femur nailing. The main outcome measures were radiologic healing and time to union. The primary healing rate after cephalomedullary nailing of bisphosphonate-associated subtrochanteric femur fractures was 68.7% (33/48 patients). Mean time to union was 10.7 months. Malalignment was determined using the differences in neck-shaft angle (the difference between the normal side and the surgically repaired side) and sagittal angulation. These all proved to be significantly correlated with failure and delayed healing time. The cutoff points for neck-shaft angle, difference in neck-shaft angle, and sagittal angulation were 125.6, 4.4, and 5.5 degrees, respectively (receiver operating characteristic curve analysis). The healing rate of atypical subtrochanteric femur fractures treated with cephalomedullary nailing is lower than that previously reported for atypical femur fractures. The quality of fracture reduction proved to be the most important factor in bony union and time to union. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Atypical Fractures Following Bisphosphonate Therapy.

Bisphosphonates have been widely used in the treatment of osteoporosis with well-documented long-term efficacy and safety, particularly in postmenopausal patients. But over the past decade, low-energy atypical subtrochanteric and proximal diaphyseal femoral fractures have emerged as an unexpected complication of prolonged bisphosphonate use. To the radiologist unfamiliar with this entity, the findings may be subtle and often missed, potentially evolving from an early incomplete fracture to a displaced complete fracture with a delay in diagnosis.In such instances where the radiographic findings are negative or equivocal and patients present with prodromal symptoms of aching or dull groin or thigh pain, additional work-up with advanced imaging techniques, such as magnetic resonance imaging, computed tomography, or bone scintigraphy, may prove diagnostic owing to their multiplanar capabilities and earlier detection of subtle periosteal changes. It is imperative that radiologists develop a search pattern to help identify such fractures and consider imaging evaluation of the contralateral extremity in suspected cases with prodromal symptoms to assess for an incomplete asymptomatic or minimally symptomatic fracture.

Hip Arthroplasty for Treatment of Atypical Femoral Fracture with Pre-existing Hip Osteoarthritis: 用全髖關節置換術來治療同時患有髖骨關節炎和非典型股骨骨折的病人：病例報告

A 72-year-old woman with bilateral hip dysplasia sustained atypical femoral fracture of the left subtrochanteric region. She underwent left total hip replacement with a long extensively porous coated femoral stem. The fracture healed with incorporation of the strut allograft after 8 months. A painful horizontal radiolucent line at the tip of the femoral stem was noted after 4 years, with resolution of symptoms after a period of protected weight bearing. We believe that total hip replacement for subtrochanteric atypical femoral fracture with pre-existing hip dysplasia is a feasible option and avoids a second operation for the treatment of osteoarthritis.

Stress fractures: pathophysiology, clinical presentation, imaging features, and treatment options.

Stress fracture, in its most inclusive description, includes both fatigue and insufficiency fracture. Fatigue fractures, sometimes equated with the term "stress fractures," are most common in runners and other athletes and typically occur in the lower extremities. These fractures are the result of abnormal, cyclical loading on normal bone leading to local cortical resorption and fracture. Insufficiency fractures are common in elderly populations, secondary to osteoporosis, and are typically located in and around the pelvis. They are a result of normal or traumatic loading on abnormal bone. Subchondral insufficiency fractures of the hip or knee may cause acute pain that may present in the emergency setting. Medial tibial stress syndrome is a type of stress injury of the tibia related to activity and is a clinical syndrome encompassing a range of injuries from stress edema to frank-displaced fracture. Atypical subtrochanteric femoral fracture associated with long-term bisphosphonate therapy is also a recently discovered entity that needs early recognition to prevent progression to a complete fracture. Imaging recommendations for evaluation of stress fractures include initial plain radiographs followed, if necessary, by magnetic resonance imaging (MRI), which is preferred over computed tomography (CT) and bone scintigraphy. Radiographs are the first-line modality and may reveal linear sclerosis and periosteal reaction prior to the development of a frank fracture. MRI is highly sensitive with findings ranging from periosteal edema to bone marrow and intracortical signal abnormality. Additionally, a brief description of relevant clinical management of stress fractures is included.

Atypical femoral fracture in a 51-year-old woman: Revealing a hypophosphatasia

We report a 51-year old woman who suffered 2 atypical subtrochanteric femoral fractures (AFFs). She had a history of several metatarsal fractures. She had a normal bone densitometry. An adult form of hypophosphatasia (HPP) was diagnosed from low serum alkaline phosphatase (ALP), and tissue nonspecific isoenzyme of ALP (TNSALP) mutation analysis revealing 2 heterozygous mutations: c.299C>T (p. T100M) and c.571G>A (p. E191K). Low ALP is the hallmark of the diagnosis of HPP; which is associated in adults with premature loss of deciduous teeth, recurrent metatarsal stress fractures, and joints and tendons disorders. The incidence of AFFs in the population is 5.9 per 100,000 person-years. Physicians and patients with bone fragility must pay attention to prodromal pain, which require urgent radiographic evaluation of both femurs. Rheumatoid arthritis, use of glucocorticoids, and proton pump inhibitors have been associated with an excess risk of AFFs. Healthy subjects carrying a TNSALP mutation with low ALP value may be exposed to develop AFF spontaneously or while receiving potent anti-resorptive drugs. Low ALP must be checked as a cause of bone fragility.

Underdiagnosis and Undertreatment of Osteoporosis: The Battle to Be Won.

An expert opinion perspective on why osteoporosis is underdiagnosed and undertreated. To highlight the potential reasons for why osteoporosis is undertreated. Literature review from PubMed, Plos One, and Science Direct search engines from 1900-2015 under terms: sub-trochanteric and atypical femur fractures, bisphosphonate clinical trial and bisphosphonate review articles, and treatment/under treatment of osteoporosis, as well as personal experience. Careful and objective review. Derived from reviews. Bisphosphonates. Atypical sub-trochanteric femur fractures. Atypical sub-trochanteric femur fractures occur in both bisphosphonate and non-bisphosphonate users; and, bisphosphonate utilization has declined in temporal relationship with the reporting of these fractures associated with bisphosphonate use. There is no causality in this association and the benefit/risk ratio of bisphosphonates reducing all fracture risk vs the potential for the development of an atypical sub-trochanteric femur fracture is exceedingly in favor of bisphosphonate use in higher risk populations. Treatments for osteoporosis should not be stopped (e.g. the "drug-holidays") in higher risk patients since the basic pathophysiology of osteoporosis continues; and, the evidence linking bisphosphonate use to causing atypical sub-trochanteric femur fractures is non-existent.

Total Hip Arthroplasty for Implant Rupture after Surgery for Atypical Subtrochanteric Femoral Fracture.

Treatment methods for delayed union and nonunion of atypical femoral fracture are still controversial. Moreover, no treatment method has been established for implant rupture caused by delayed union and nonunion. We encountered a 74-year-old female in whom nonunion-induced implant rupture occurred after treatment of atypical subtrochanteric femoral fracture with internal fixation using a long femoral nail. It was unlikely that sufficient fixation could be obtained by repeating osteosynthesis alone. Moreover, the patient was elderly and early weight-bearing activity was essential for early recovery of ADL. Based on these reasons, we selected one-stage surgery with total hip arthroplasty and osteosynthesis with inverted condylar locking plate as salvage procedures. Bone union was achieved at 6 months after surgery. This case illustrated that osteosynthesis-combined one-staged total hip arthroplasty could be considered as one of the options for nonunion-induced implant rupture of atypical femoral subtrochanteric fracture.

Atypical subtrochanteric femur fracture in two patients with metastatic breast cancer treated with zoledronic acid and denosumab

Atypical subtrochanteric femur fracture in two patients with metastatic breast cancer treated with zoledronic acid and denosumab

Subtrochanteric Fracture as First Sign of Metastatic Breast Cancer: Case Presentation

Atraumatic subtrochanteric fractures represent a serious injury of the lower limb as they represent the clinical expression of a preexisting pathology. Atypical subtrochanteric femur fractures can result from long-term bisphosphonate therapy but a primary or metastatic tumor of the proximal femur should always be included in the differential diagnosis. We present the case of a young female patient without any previous pathological conditions that presented to the emergency room with a subtrochanteric fracture. She was admitted to our clinic and treated with a long cephalomedullary device (CMD). Tissue from the fracture zone was harvested and sent for a pathology analysis. While pathologic bone fractures are not a new entity by any mean in orthopedic practice, they seldom are the first sign of a metastatic disease. This presents a therapeutic challenge especially in young patients because of the reserved overall prognosis in the medium and long term. Better screening methods should be employed in a bid to eliminate this category of patients. We consider this case of a young woman with undetected breast cancer and one skeletal-related event (SRE) in the form of a pathological bone subtrochanteric fracture as an interesting development of the underlying pathology since as the literature shows these cases are quite rare and she did not present any of the usual symptoms associated with a bone metastasis. J Med Cases. 2015;6(8):367-372 doi: http://dx.doi.org/10.14740/jmc2216w

Treating Atypical Femoral Fractures Related to Bisphosphonates.

Doctors widely prescribe osteoclast-inhibiting bisphosphonate drugs to treat osteoporosis, but long-term bisphosphonate use has been linked to an increased risk of atypical subtrochanteric femoral fractures. According to an updated task force report from the American Society for Bone and Mineral Research, the features that distinguish these atypical subtrochanteric fractures include transverse orientation, general lack of comminution, and localized cortical thickening at the fracture site. In addition, the prolonged healing times of these fractures challenge orthopaedists to obtain strong and stable fixation that outlasts the extended period required for fracture union. Intramedullary nailing is often used to treat these fractures, but related characteristics such as canal narrowing can make this fixation approach unfeasible. This month’s “Case Connections” looks at various techniques for repairing bisphosphonate-associated atypical femoral fractures. In the January 14, 2015, JBJS Case Connecto r , Yuasa et al. reported on the case of a sixty-nine-year-old woman who, one month prior to scheduled right hip arthroplasty to treat osteoarthritis, presented with severe right thigh pain after a low-trauma fall. History-taking revealed four-plus years of treatment with alendronate (Fosamax), and radiographs showed a noncomminuted transverse subtrochanteric fracture below an arthritic hip joint. During a single operation, the patient underwent cementless total hip arthroplasty using a modular stem/neck, followed by fracture reduction and fixation using a cable-and-plate system (Fig. 1). The patient was switched from alendronate to a …

Atypical Subtrochanteric Femoral Fracture Below an Arthritic Hip: A Case Report.

We present a case of a sixty-nine-year-old woman with an atypical subtrochanteric femoral fracture below an arthritic hip; the patient had a history of long-term bisphosphonate treatment. We performed a one-stage total hip arthroplasty with a plate and cables because the healing of atypical femoral fractures in patients with a history of bisphosphonate use can be prolonged. The combined use of a plate and total hip arthroplasty is a potential intervention for atypical proximal femoral fractures associated with hip arthritis.