Spinal Versus General Anesthesia and Inflammatory Response Measured by Delta Neutrophil Index in Total Knee Arthroplasty: An Observational Study

This prospective observational study will be conducted at Elazig Fethi Sekin City Hospital, Department of Anesthesiology and Reanimation. Patients undergoing total knee arthroplasty will be assigned to two groups based on the anesthesia method used in routine practice: spinal anesthesia or general anesthesia. The primary outcome measure is the Delta Neutrophil Index (DNI), an inflammation marker automatically calculated by hematology analyzers using complete blood count parameters. DNI values will be compared preoperatively and postoperatively between groups. Additional data including age, sex, ASA classification, duration of surgery, hemogram parameters, and perioperative complications will be collected. The sample size calculation indicated that a minimum of 42 patients per group (total 84) are required to detect significant differences in DNI levels with 80% power at a 5% significance level. Statistical analyses will include Kolmogorov-Smirnov test for normality, independent t test or Mann-Whitney U test for between-group comparisons, and paired t test or Wilcoxon test for within-group comparisons. A p-value <0.05 will be considered statistically significant.

Inclusion criteria

• Patients scheduled for total knee arthroplasty
• Age ≥ 18 years
• ASA physical status classification I-III

Exclusion criteria

• Active infection
• Hematologic disease (e.g., leukemia, aplastic anemia)
• Autoimmune or chronic inflammatory disease
• Use of corticosteroids or immunosuppressive drugs
• Malignancy
• Acute trauma or sepsis
• Pregnancy