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< Back Diabetic Foot Ulcers diabetic-foot-ulcers Previous Next

< Back Alper DUNKI Clinical Research, Statistical Concepts, and Tests Spot Knowledge – Clinical Research & Statistical Tests Risk & Effect: Absolute Risk Increase = harm Absolute Risk Reduction = benefit Effect size = magnitude of difference Bayesian analysis = prior + new evidence p-value: Probability result occurred by chance; ≠ clinical relevance Confidence Interval: Precision & range of true effect Ratios: Odds ratio, risk ratio, hazard ratio → compare risk between groups Evidence Synthesis: Systematic review & meta-analysis = stronger evidence Forest plot = visual pooled effect Statistical vs Clinical Significance: Not always the same CONSORT: Standardised reporting of RCTs Presentation of Findings in Clinical Research, Statistical Concepts, and Tests Basic Concepts In clinical research, risk, effect, and outcomes are quantified using various statistical methods. Absolute risk increase indicates a harmful effect, whereas absolute risk reduction reflects a beneficial intervention. Bayesian analysis begins with a prior probability and updates it with new data. Blinding is employed to reduce bias. Outcomes may be dichotomous (e.g., presence/absence of disease) or continuous variables (e.g., blood pressure value). Effect size expresses the difference between two groups using standardized measures. Statistical Methods The p-value represents the probability that the observed result occurred by chance. However, it does not, on its own, indicate clinical relevance. Confidence intervals reflect the precision of an estimate. Odds ratio, risk ratio, and hazard ratio measure differences in probabilities or time-related risks between groups. Meta-analyses and systematic reviews increase the strength of evidence by pooling data from multiple studies. A forest plot provides a visual summary of individual study results and overall effect. Presentation of Findings Distinguishing between statistical significance and clinical significance is essential. A statistically significant difference may not always be clinically meaningful. Tables and figures facilitate transparent reporting of findings. CONSORT guidelines ensure standardized reporting of randomized controlled trials. Statistical Tests and Applications Chi-square test (χ²): Examines the association between two categorical variables (e.g., treatment groups and recovery rate). Fisher’s exact test: Preferred for categorical data with small sample sizes. Student’s t-test: Compares continuous variable means between two groups; assumes normal distribution. Mann-Whitney U test: Used for comparing two groups when continuous data are not normally distributed. Paired t-test: Compares pre- and post-intervention values within the same group. Wilcoxon signed-rank test: Suitable for paired non-normally distributed data. ANOVA: Assesses mean differences among three or more groups; assumes normality and homogeneity of variance. Kruskal-Wallis test: Nonparametric alternative for comparing three or more groups. Correlation tests: Pearson correlation evaluates linear associations between continuous variables; Spearman correlation is used for ordinal or non-normally distributed variables. Regression analyses: Describe the relationship between a dependent variable and one or more independent variables. Logistic regression is applied for dichotomous outcomes. Kaplan-Meier analysis: Demonstrates time-to-event probabilities in survival analysis. Log-rank test: Compares survival curves between two groups. Cox regression: Assesses the impact of multiple variables on survival outcomes. Clinical Decision-Making Interpretation of evidence should consider not only statistical outcomes but also patient benefit, adverse effects, and feasibility. Clinical research findings must be integrated with individual patient characteristics and physician expertise. References 1. Rovetta A. P-values and confidence intervals as compatibility measures. J Transl Med . 2025 doi:10.1186/s12967-025-? 2. Phillips MR, Wykoff CC, Thabane L, Bhandari M, Chaudhary V. The clinician’s guide to p values, confidence intervals, and magnitude of effects. Eye (Lond) . 2022;36:341–342. doi:10.1038/s41433-021-01863-w 3. van Zwet E, Tong TJK. A new look at P values for randomized clinical trials. NEJM Evid . 2023;2(6):? (sayfa no). doi:10.1056/EVIDoa2300003 Previous Next

< Back Elbow Deformity Correction elbow-deformity-correction Previous Next

< Back Open Fracture Management Open fractures require urgent assessment, debridement, and staged fixation to minimise infection and optimise outcomes. Galeazzi fracture is a distal radial shaft fracture with dislocation of the distal radioulnar joint (DRUJ). Internal fixation of the radius and assessment of DRUJ stability are essential. open-fracture Previous Next

< Back Dr. Serkan BAYRAM Endoprosthesis Endoprosthetic reconstruction is a cornerstone technique in musculoskeletal oncology, allowing immediate restoration of skeletal continuity and early mobilization after wide tumor resection. Modern modular megaprostheses, made of titanium or cobalt-chromium alloys, are designed for durability, functional recovery, and ease of revision. They are primarily indicated for periarticular or diaphyseal bone loss following tumor excision, failed fixation, or pathological fractures. Cemented fixation ensures immediate stability, while press-fit and porous-coated designs promote biological integration. Despite excellent limb salvage rates (>90%), complications such as infection, aseptic loosening, and mechanical failure remain challenges. Advances including silver-coated implants, expandable pediatric prostheses, and improved soft-tissue reattachment techniques continue to enhance long-term outcomes and quality of life for oncology patients. Definition An endoprosthesis is a modular metallic implant used to reconstruct bone and joint defects following wide resection of primary or metastatic musculoskeletal tumors. The aim is to achieve immediate structural stability , preserve limb function, and allow early mobilization, particularly in cases where biological reconstruction (allograft or autograft) is not feasible. Indications Segmental bone loss after tumor resection, particularly in the proximal humerus , distal femur , and proximal tibia . Periarticular destruction due to primary bone sarcomas (e.g., osteosarcoma, Ewing sarcoma) or metastatic disease. Reconstruction after pathological fractures or failed fixation in oncologic bone. Salvage after infection or mechanical failure of previous reconstruction. Design and Components Modern tumor prostheses are modular megaprostheses made from titanium or cobalt-chromium alloys, often with: Cemented or press-fit stems for fixation into the remaining diaphysis. Rotating hinge joints (knee and elbow) to reduce torque and wear. Porous-coated or hydroxyapatite collars to promote soft-tissue and bone integration. Expandable designs for skeletally immature patients, allowing non-invasive limb-length adjustment. Cemented fixation offers immediate stability, while cementless (press-fit) fixation supports long-term biological fixation and easier revision. Surgical Principles Wide oncologic margins are mandatory to minimize local recurrence. Preservation of neurovascular structures and soft-tissue coverage is essential. Stable fixation and restoration of limb length should be achieved intraoperatively. Reconstruction of muscle attachments (especially in proximal humerus and tibia) improves functional outcome. Prophylactic antibiotic cement or silver-coated implants are used to reduce infection risk in high-risk cases. Advantages Immediate load-bearing capability. Shorter operative time compared to biological reconstructions. Predictable early function and pain relief. Can be revised modularly if components wear or fracture. Complications Infection (5–15%); more common in immunocompromised or irradiated patients. Mechanical failure (loosening, stem breakage). Aseptic loosening due to stress shielding. Periprosthetic fracture and soft-tissue failure (e.g., extensor mechanism insufficiency). Outcomes and Prognosis Endoprosthetic reconstructions provide excellent pain relief and limb salvage rates exceeding 90% in modern series. Five-year implant survival is around 70–80% , depending on site and indication. Long-term durability is enhanced by improved modular designs, better fixation strategies, and multidisciplinary care. References Rizzo SE, Kenan S. Pathologic Fractures. StatPearls Publishing, 2025. Fields RC et al. Management of Pathological Fractures: Current Consensus. Knee Surg Sports Traumatol Arthrosc , 2024. Boussouar S et al. Tailored Approach for Appendicular Pathologic Fractures from Metastatic Bone Disease. Cancers (Basel) , 2022. Jeys L, Grimer R. Endoprosthetic Reconstruction After Tumor Resection. J Bone Joint Surg Br , 2019. Henderson ER et al. Failure Mode Classification for Tumor Endoprostheses: An International Consensus. Clin Orthop Relat Res , 2017. Quick Facts Feature Details Purpose Reconstruction of segmental bone or joint defects after tumor resection Main Indications Primary or metastatic bone tumors, failed fixation, post-infection salvage Common Sites Distal femur, proximal tibia, proximal humerus, proximal femur Design Type Modular or custom-made megaprostheses (cemented or press-fit fixation) Expandable Prostheses Used in skeletally immature patients to allow limb-length adjustment Key Materials Titanium, cobalt-chromium alloys, silver-coated or hydroxyapatite collars Advantages Immediate stability, early mobilization, predictable limb function Common Complications Infection (5–15%), aseptic loosening, mechanical failure, periprosthetic fracture Functional Outcome Limb salvage rate >90%; 5-year implant survival 70–80% Preferred in Large bone defects or periarticular resections where biological grafting is not feasible Previous Next

< Back Dr. Özcan KAYA He was born in 1983. Following his pre-undergraduate studies, he began his medical education at Istanbul University's Istanbul Faculty of Medicine in 2001 and earned his MD in 2007. He completed his residency at Istanbul University's Istanbul Faculty of Medicine and became an Orthopedics and Traumatology Specialist in 2013. During his residency, he served as a spine surgery observer at Thomas Jefferson University & Rothmann Institute, one of the leading spine clinics in the United States, examining patients and participating in surgeries. He continues to practise at Istanbul Biruni Hospital. For more info, visit https://drozcankaya.com.tr/ Spine ozcankaya.md@gmail.com Previous Next

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< Back Scaphoid Fractures scaphoid-fractures Previous Next

< Back Dr. Hakan ESKARA University of Health Sciences, Istanbul, Sancaktepe City Prof. Dr. Ilhan Varank Health Application and Research Center Oncologic Orthopaedics, Sports Medicine hakaneskara@gmail.com Previous Next

Arthroplasty General Principles Indications for Arthroplasty Implant Designs & Materials Preoperative Planning Periprosthetic Joint Infection Postoperative Rehabilitation Hip Arthroplasty Total Hip Arthroplasty (THA) Hip Approaches Revision Hip Arthroplasty Periprosthetic Hip Fractures Dislocation & Instability Knee Arthroplasty Total Knee Arthroplasty (TKA) Knee Approaches Unicompartmental Knee Arthroplasty (UKA) Revision Knee Arthroplasty Ligament Balancing in TKA Patellofemoral Arthroplasty Special Considerations Robotic Assisted UKA Robotic Assisted TKA Robotic Assisted THA Myths and in Arthroplasty

< Back Complex Limb Salvage complex-limb-salvage Previous Next