Biological activity is not suppressed in mid-shaft stress fracture of the bowed femoral shaft unlike in “typical” atypical subtrochanteric femoral fracture: A proposed theory of atypical femoral fracture subtypes

Oh, Yoto; Yamamoto, Kouhei; Hashimoto, Jun; Fujita, Koji; Yoshii, Toshitaka; Fukushima, Kazuyuki; Kurosa, Yoshiro; Wakabayashi, Y.; Kitagawa, Masanobu; Okawa, Atsushi

doi:10.1016/j.bone.2020.115453

Cited by 28 publications

(31 citation statements)

References 33 publications

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“…In recent years there have been several reports using FEA to characterize stresses around an AFF ( Sasaki et al, 2012 ; Maratt et al, 2014 ; Oh et al, 2020 ; Demirtas et al, 2020 ). Oh et al demonstrated that significant tensile stress caused by bowing of the femoral shaft is associated with AFFs.…”

Section: Discussionmentioning

confidence: 99%

“…Incomplete fractures showed a fracture gap containing an amorphous, non-mineralized material, callus, cartilage matrix and fragments of lamellar bone, probably broken off from the fracture surface in the gap. Adjacent to the fracture line, many resorption cavities and channels are observed and tended to be oriented perpendicular to the fracture plane, but some channels run transversely ( Schilcher et al, 2014 ; Oh et al, 2020 ). Osteoclasts were frequently found close to the fracture line in the resorption cavities and less frequently further away.…”

Section: Introductionmentioning

confidence: 99%

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Disturbance of osteonal bone remodeling and high tensile stresses on the lateral cortex in atypical femoral fracture after long-term treatment with Risedronate and Alfacalcidol for osteoporosis

et al. 2021

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An 83 year-old Japanese woman complained of left lateral thigh pain following a low-energy fall 4 months prior to admission. She had been treated for osteoporosis with Risedronate and Alfacalcidol for the previous five years. She was diagnosed with an atypical femoral fracture (AFF) according to the American Society for Bone and Mineral Research (ASBMR) Task Force revised criteria. Radiographs revealed cortical thickening and a transverse radiolucent fracture line in the lateral cortex of the shaft. MRI showed a high intensity signal on the T2WI image 1 cm long in the lateral cortex. The patient had normal levels of bone resorption and formation biomarkers except for low 25(OH) Vitamin D. Double fluorescent labeling was done preoperatively. Due to significant bowing, a corrective osteotomy and intramedullary nailing were performed, and the resected bone wedge was analyzed by bone histomorphometry. Three ground sections of the lateral cortex at the fracture site showed many and large pores, with or without tetracycline labeling. Histomorphometric assessment was done on intracortical pores, classified by a novel criteria, only to assess size of the pores to know prolonged osteoclastic activity and its characteristics of inner surfaces to assess whether bone formation has been occurring or not in labeling period in remodeling cycle, and coalition of multi-pores. Increased size with widespread variation of pores suggested prolonged osteoclastic activity in the reversal/resorptive phase. Bone labeling showed lamellar bone on the endocortical surface. We hypothesize that the case had developed from a regional disturbance of osteonal remodeling in the lateral cortex, in which accumulated microcracks might have initiated a resorption process resulting in resorption cavities, i.e., pores, which became larger due to prolonged activity of secondary osteoclasts. Various sized pores could form lamellar bone, still forming at the time of biopsy, some had formed lamellar bone, but stopped to form before labeling and not to start to form at all, probably due to incomplete coupling. Endocortical lamellar bone might had started to resorbed to smooth off endocortical surface, followed by formation of lamellar bone. The endocortical bone formation was assessed and its formation period is about 2.7 years. A finite element analysis using preoperative CT data revealed high tensile stresses on the lateral aspect of the femur. Histomorphometric results suggest that there might be more pores in the tensile area than the compressive area. These findings may subsequently connect accumulation of microcracks, an increase of size and number of pores and coalition and subsequent fracture in the lateral cortex.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Disturbance of osteonal bone remodeling and high tensile stresses on the lateral cortex in atypical femoral fracture after long-term treatment with Risedronate and Alfacalcidol for osteoporosis

et al. 2021

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“…Healing of these fractures tends to be delayed because of widespread suppression of bone turnover ( Figure 2 ). 4 – 6 , 12 , 23 – 27 Other factors potentially involved in the pathogenesis of AFF include ethnicity, 4 body mass index, 20 loading stress in daily life, 7 – 10 femoral morphology, 6 – 8 , 11 , 12 , 14 , 28 , 29 and bone density, quality, and strength. 12 – 14 Mild mechanical stress during daily activities is undoubtedly involved in the onset of AFF.…”

Section: Atypical Fracturesmentioning

confidence: 99%

“…4 – 6 , 12 , 23 – 27 Other factors potentially involved in the pathogenesis of AFF include ethnicity, 4 body mass index, 20 loading stress in daily life, 7 – 10 femoral morphology, 6 – 8 , 11 , 12 , 14 , 28 , 29 and bone density, quality, and strength. 12 – 14 Mild mechanical stress during daily activities is undoubtedly involved in the onset of AFF. 4 , 6 – 10 Mechanical studies using finite-element methods by our research group and Haider et al have demonstrated that the distribution of tensile stress in the femoral shaft as a result of everyday loading stress is affected by femoral morphology (e.g.…”

Section: Atypical Fracturesmentioning

confidence: 99%

Current concept of stress fractures with an additional category of atypical fractures: a perspective review with representative images

Yamamoto

Yoshii

et al. 2021

Therapeutic Advances in Endocrinology

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Stress fractures have traditionally been classified into three categories: fatigue fractures due to overuse of bone with normal elastic resistance; insufficiency fractures due to everyday physiological stress on fragile bone with poor elastic resistance; and pathologic fractures due to bone weakness involving tumors. The concept of atypical fractures has emerged and is considered a type of stress fracture. However, there has been some inconsistency in interpretation when using the traditional classification of stress fractures, and atypical femoral fractures (AFFs) can potentially be classified into subtypes: “typical” AFFs involving bone turnover suppression due to specific drugs (e.g. bisphosphonates) and fragility fractures of the bowed femoral shaft. In this article, the classification of stress fractures is redefined with the addition of atypical fractures as a fourth category, in which biological activity for fracture healing is absent, to promote consistent understanding and interpretation of clinical conditions involving stress fractures.

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“…Eine seltene, aber sehr folgenreiche Nebenwirkung von Bisphosphonaten oder Denosumab kann eine atypische Femurfraktur (AFF) sein, die durch eine verminderte "Bruchzähigkeit" am Femurschaft ohne oder bei nur geringen Traumata auftritt, wobei Subtypen von Knochenstoffwechselveränderungen eine Rolle spielen dürften [10]. Auch wenn das absolute Risiko einer AFF sehr niedrig im Vergleich zur therapiebedingten Verminderung von Hüftfrakturen ist, steigt diese Komplikation dennoch mit einer längeren Therapiedauer an, sinkt aber nach Absetzen der Therapie rasch ab [11].…”

Section: Atypische Femurfrakturenunclassified

Langfristige Therapiekonzepte bei Osteoporose

2021

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ZusammenfassungDie Notwendigkeit einer Langzeittherapie bei Osteoporose, eine teils eingeschränkte Compliance, aber auch die Möglichkeit von erheblichen Nebenwirkungen bei einer pharmakologischen Osteoporosetherapie beschäftigen sowohl die medizinischen Richtlinien als auch die Betroffenen in vielfacher Weise. In dieser Übersicht wird auf den Stand der zur Verfügung stehenden Osteoporosepharmazeutika und die aktuellen wissenschaftlich fundierten Grundlagen einer langjährigen Anwendung, das potenzielle Monitoring und mögliche Therapieänderungen mit dem spezifischen Augenmerk auf künftige Entwicklungen eingegangen.

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Biological activity is not suppressed in mid-shaft stress fracture of the bowed femoral shaft unlike in “typical” atypical subtrochanteric femoral fracture: A proposed theory of atypical femoral fracture subtypes

Cited by 28 publications

References 33 publications

Disturbance of osteonal bone remodeling and high tensile stresses on the lateral cortex in atypical femoral fracture after long-term treatment with Risedronate and Alfacalcidol for osteoporosis

Disturbance of osteonal bone remodeling and high tensile stresses on the lateral cortex in atypical femoral fracture after long-term treatment with Risedronate and Alfacalcidol for osteoporosis

Current concept of stress fractures with an additional category of atypical fractures: a perspective review with representative images

Langfristige Therapiekonzepte bei Osteoporose

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