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< Back Dr. Savas CAMUR Periprosthetic Hip Fractures Vancouver B2 fractures—those with a loose stem but adequate bone stock—remain the most debated subtype in terms of optimal management, with recent meta-analyses redefining treatment algorithms.Periprosthetic femoral fractures (PPF) represent one of the most challenging complications after total hip arthroplasty (THA). Their incidence is rising sharply worldwide, driven by increasing THA volumes, aging populations, and poor bone health, particularly osteoporosis. Periprosthetic Hip Fractures Epidemiology & Trends Incidence: PPFs occur in 0.1–3.5% of all THAs and are among the leading causes of revision surgerys Rising burden: U.S. data (2010–2019) demonstrate a +7% annual growth in 2-year PPF incidence, nearly doubling since 2010 At-risk populations: Age < 50 years Osteoporosis Vitamin D deficiency Medicaid recipients These findings emphasize socioeconomic disparities and bone-quality-related vulnerability. Pathophysiology & Biomechanics Osteoporosis contributes directly to the pathogenesis of PPFs by altering both bone mineral density (BMD) and microarchitecture : Trabecular perforation and cortical thinning reduce load transfer capacity. Weakened osseointegration diminishes stem anchorage, increasing micromotion and loosening. This fragile biomechanical environment sets the stage for PPF even under low-energy trauma or routine postoperative stress.Animal and human models confirm that osteoporotic bone shows reduced periprosthetic bone formation and inferior implant fixation. Risk Factors CategorySpecific FactorsPatient Older age, female sex, low BMI, vitamin D deficiency, chronic corticosteroid use, smoking, alcohol, rheumatoid arthritisImplant/Bone Osteoporotic bone, cementless stems (especially in Dorr C femurs), poor osseointegrationSurgical Undersized stem, eccentric reaming, improper alignment, absence of cement in poor bone qualitySystemic Chronic kidney disease, endocrine disorders (thyroid/parathyroid), malnutrition Classification The Vancouver Classification remains the standard: Type B1: Stable stem Type B2: Loose stem, adequate bone stock Type B3: Loose stem, poor bone stock The Unified Classification System (UCS) expands this to periprosthetic fractures beyond the femur. Treatment Options 1. Osteosynthesis (ORIF) Indications: Low-demand, frail patients (ASA ≥ 3), multiple comorbidities, acceptable bone stock. Advantages: Shorter operative time (≈120 min vs 173 min for revision) Lower blood transfusion rate (44% vs 53%) Fewer complications and reoperations Similar 1-year mortality (~13%)s00198-025-07583-1 Techniques: Locking plate ± cables or cerclage Biological fixation with bridging constructs Avoid excessive stripping of periosteum Goal: achieve relative stability rather than perfect anatomic reduction 2. Revision Arthroplasty Indications: Younger, active patients; poor implant stability; severe osteolysis or bone loss. Approach: Long, diaphyseal-engaging revision stem (cementless or cemented) Extended trochanteric osteotomy if necessary Address offset, version, and limb length Drawbacks: Longer surgery, higher bleeding and infection risk, increased dislocation rates 3. Role of Cemented Fixation Hybrid THA (cemented stem + press-fit cup) yields significantly lower PPF rates in osteoporotic patients (hazard ratio 7.7 for uncemented vs cemented stems) Cemented constructs are particularly advantageous in elderly (> 65 years) and Dorr C femurs. Clinical Decision Pearls Always confirm stem stability intraoperatively before deciding against revision. In osteoporotic bone, avoid under-reaming ; consider cemented fixation. ORIF is viable for low-demand elderly or comorbid patients with adequate bone stock. Preoperative bone health optimization (vitamin D, calcium, bisphosphonates, denosumab) can reduce postoperative PPF risk. Functional outcomes (Parker Mobility, Harris Hip Score) show no significant difference between ORIF and revision. Future Directions Pre-THA bone health screening using DXA or FRAX is underutilized and should be standardized. Augmented reality navigation and AI-assisted risk scoring may improve preoperative planning. Novel biologic bone enhancers (anabolic agents, PTH analogs, sclerostin inhibitors) show promise in reducing fragility-related complications. Registry-based big data analysis will continue refining patient-specific algorithms for PPF management. Decision-Making Flowchart: Management of Vancouver B2 Periprosthetic Hip Fractures Step 1: Confirm Diagnosis Imaging: X-ray + CT (for stem stability, bone stock, osteolysis) Exclude infection: ESR, CRP, joint aspiration → If infection positive → Two-stage revision (exclude from this algorithm) Step 2: Assess Stem Stability Stable stem → → Vancouver B1 → Fixation (ORIF) Loose stem → → Vancouver B2 → Proceed below Step 3: Evaluate Patient Factors Table 1 💡 Rule of thumb: “Fix frail, revise fit.” If patient unlikely to tolerate prolonged surgery or blood loss → choose osteosynthesis . Step 4: Evaluate Bone and Implant Conditions Table 2 Step 5: Select Surgical Strategy If ORIF selected: Use locking plate ± cerclage ; avoid excessive stripping. Achieve relative stability → biological fixation concept. Allow partial weight bearing at 6–8 weeks. Post-op early geriatric rehab essential. If Revision selected: Long diaphyseal-engaging stem (cementless or cemented) Consider Extended Trochanteric Osteotomy (ETO) if necessary. Restore offset, limb length, and version. Consider dual-mobility or constrained liner for instability risk. Step 6: Postoperative Protocol ORIF group: Gradual weight bearing; follow radiographs every 6–8 weeks. Revision group: Early protected mobilization; DVT prophylaxis mandatory. All patients: Evaluate bone health (vitamin D, calcium, antiresorptives). Step 7: Expected Outcomes Table 3 References: González-Martín D et al. Eur J Trauma Emerg Surg. 2023. .Zhao A Y et al. Osteoporosis Int. 2025;36:1371–77s00198-025-07583-1 .Bauer J et al. Curr Osteoporos Rep. 2025;23:29s11914-025-00922-5 Stoffel K et al. Arch Orthop Trauma Surg. 2020. Lewis DP et al. J Orthop Trauma. 2021. 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< Back Alper DUNKI Cellular and Molecular Biology, Immunology and Genetics Terminology Spot Knowledge The nucleus stores DNA; nucleolus produces ribosomes. Defects cause syndromes with skeletal anomalies. Mitochondria are key for ATP; dysfunction leads to neuromuscular and metabolic disease. Lysosomes degrade waste; defects → storage disorders (e.g., Tay-Sachs). ECM (collagen, GAGs, proteoglycans) provides structural support and lubrication. Stem cells : mesenchymal stem cells can differentiate into osteoblasts and chondrocytes. Cellular Structures and Functions Nucleus & Nucleolus: Store genetic material, produce ribosomes. Syndromes: Bloom, Treacher Collins, Rothmund-Thomson. Cytoplasm: Site of metabolism. Mitochondria: ATP production, signaling. Mutations → neuromuscular disease, diabetes, deafness. Golgi apparatus: Packages proteins/hormones; linked to secretion disorders. Lysosomes: Waste degradation; lysosomal storage diseases (Tay-Sachs, Gaucher). Endoplasmic Reticulum: Protein & lipid synthesis. Ribosomes: Protein synthesis; ribosomopathies. .Cytoskeleton: Shape, motility; defects → cardiomyopathy, genetic deafness1. Cellular and Molecular Biolo… Extracellular Matrix (ECM) Provides scaffolding for tissues. Components: Collagen (main structural protein), GAGs , fibronectin , laminin . .GAGs + proteoglycans → cushioning, lubrication1. Cellular and Molecular Biolo… Intracellular Signal Transduction Mediated via receptors: GPCRs, ion channels, tyrosine kinases. Second messengers: cAMP, Ca²⁺. .Control gene expression and cellular responses1. Cellular and Molecular Biolo… DNA & Genetics DNA: Double-stranded, stores genetic info. Genes: Exons (coding) + introns (non-coding). Promoters/Enhancers: Regulate expression. Mutations: Basis of inherited disease (Down, DiGeorge). Mitochondrial DNA: Maternal inheritance. .SNPs & Epigenetics: Variation and environment-driven expression1. Cellular and Molecular Biolo… RNA Biology mRNA: Protein coding. miRNA: Gene regulation. .rRNA: Part of ribosome, diagnostic use in bacteria1. Cellular and Molecular Biolo… Gene Expression & Protein Synthesis Transcription: DNA → RNA. Translation: RNA → protein. Transcription factors (RUNX2, SOX9, PPAR-γ) regulate bone and cartilage differentiation. .Post-translational modifications: glycosylation, phosphorylation1. Cellular and Molecular Biolo… Molecular Biology & Protein Techniques FISH, CGH: Detect chromosomal abnormalities. Flow cytometry: Cell surface antigens. PCR/RT-PCR: Gene amplification. Blotting (Northern/Southern): Nucleic acid analysis. Microarray: Gene expression profiles. Recombinant DNA: Produces proteins (e.g., BMP-2, IL-6 inhibitors). .Immunohistochemistry, ELISA, Western blot: Protein detection/quantification1. Cellular and Molecular Biolo… Immunology Innate immunity: Fast, nonspecific. Adaptive immunity: Antigen-specific, memory formation. Humoral: B-cell mediated. Cellular: T-cell mediated. .Inflammation in connective tissue → osteoclastogenesis → bone resorption1. Cellular and Molecular Biolo… Stem Cells Adult stem cells: Self-renewal & tissue repair. Mesenchymal stem cells: Differentiate into bone, cartilage. Embryonic stem cells: Pluripotent, rejection risk. .Induced pluripotent stem cells: Reprogrammed somatic cells with pluripotency1. Cellular and Molecular Biolo… Organelle Function Clinical Relevance Nucleus Stores DNA Cancer karyotyping, mitotic abnormalities Nucleolus Ribosome synthesis Bloom, Treacher Collins, Rothmund-Thomson Mitochondria ATP production Neuromuscular disease, diabetes, deafness Lysosome Waste degradation Tay-Sachs, Gaucher, Niemann-Pick Golgi Apparatus Protein packaging Secretion disorders Endoplasmic Reticulum Protein/lipid synthesis Liver & muscle diseases Ribosomes Protein synthesis Ribosomopathies, macrocytic anemia Cytoskeleton Shape & motility Cardiomyopathy, hearing loss References Valls AF, et al. Nat Rev Mol Cell Biol . 2022. Krajnik B, et al. Front Cell Dev Biol . 2020. Levoin N, et al. Front Cell Dev Biol . 2020. .Meng F, et al. Trends Cell Biol . 20241. Cellular and Molecular Biolo… Previous Next