Journal of Musculoskeletal Trauma

Case Report

Paradoxical hypertrophy as a cause of femoral insufficiency fractures analyzed through differences in force application in Korea: three case reports: Yong-Uk Kwon, Dae-Hyun Park, Hyoung-Gu Kang; J Musculoskelet Trauma 2026;39(2):174-180. Published online April 23, 2026; DOI: https://doi.org/10.12671/jmt.2025.00388

Abstract PDF: Previous studies have extensively examined the association between femoral insufficiency fractures and prolonged bisphosphonate therapy. However, alternative etiologies remain insufficiently characterized. This study aimed to analyze nonpharmacologic factors associated with femoral insufficiency fractures, with particular emphasis on paradoxical cortical hypertrophy and altered biomechanical load distribution. We reviewed three cases of femoral insufficiency fracture that were surgically treated at our institution between January 2018 and January 2022. None of the patients had a history of bisphosphonate use. Clinical histories—including underlying comorbidities, prior surgical procedures, and radiographic findings—were evaluated. Serial radiographs obtained before and after fracture occurrence were analyzed to characterize fracture morphology and associated cortical changes. Case 1 involved a patient with posttraumatic hip synostosis; case 2 involved a patient with osteogenesis imperfecta; and case 3 involved a patient who had previously undergone intramedullary nailing for an intertrochanteric fracture. Lateral femoral bowing and cortical hypertrophy preceded fracture development in two cases, whereas focal cortical hypertrophy at the distal locking screw site was observed in the third case. No history of bisphosphonate therapy was identified in any patient. Fractures developed at sites characterized by increased cortical remodeling and abnormal load concentration. Femoral insufficiency fractures can occur in the absence of bisphosphonate therapy. Paradoxical cortical hypertrophy and altered biomechanical force distribution appear to be important contributing factors. Level of evidence: IV.

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Review Article

Atypical femoral fractures: an update: Won-Tae Cho, Jeong-Hyun Koh, Seungyeob Sakong, Jung-Taek Kim; J Musculoskelet Trauma 2025;38(2):41-52. Published online March 28, 2025; DOI: https://doi.org/10.12671/jmt.2025.00031

Abstract PDF

This narrative review provides an up-to-date overview of atypical femoral fractures (AFFs), emphasizing diagnostic criteria, epidemiology, pathophysiology, risk factors, and evaluation with screening strategies. AFFs are rare but significant complications associated with prolonged bisphosphonate (BP) therapy for osteoporosis. Although the pathogenesis of AFFs has not been fully elucidated, its primary mechanism is thought to involve impaired bone remodeling, leading to unhealed microfractures that progress to stress fractures under repetitive loading. AFFs can occur in various regions of the femur, influenced by femoral geometry and the lower limb axis. Other risk factors include prolonged steroid use, arthroplasty, genetic predispositions, and metabolic bone disorders. The diagnosis of AFFs is based on criteria established by the American Society for Bone and Mineral Research. Key radiographic features include lateral cortical transverse fracture lines and localized cortical thickening, typically with minimal or no comminution on the medial cortex. Dual-energy X-ray absorptiometry for screening tests and magnetic resonance imaging as an advanced imaging modality enable the early detection of incomplete fractures. This multi-modal approach facilitates the prompt identification of prodromal cortical changes, reducing the risk of complete fractures in high-risk populations, particularly patients undergoing prolonged BP therapy. Level of Evidence: V

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Atypical Femur Fractures Without Bisphosphonate Exposure (AFFwB): A Retrospective Report of 21 Cases
Lorenzo Lucchetta, Carmelinda Ruggiero, Samuele Berardi, Alice Franceschi, Michele Bisaccia, Giuseppe Rinonapoli
Journal of Clinical Medicine.2025; 15(1): 25. CrossRef

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