Predictors of 90-Day All-Cause Morbidity, Mortality and Poor Functional Outcome Scores Following Elective Total Knee Arthroplasty in a High-Volume Setting: A Prospective Cohort Study.

Background: The primary objective was to ascertain the predictors of 90-day all-cause morbidity, mortality and poor functional outcome scores following primary total knee arthroplasty (TKA).

Material And Method: The study population comprised 3645 patients who underwent elective primary unilateral TKA at our institution. Demographic variables, Body Mass Index (BMI), American Society of Anesthesiologists (ASA) grade and the Deyo-Charlson comorbidity scores were ascertained. The Functional outcomes, perioperative complications, mortality and readmission rates were monitored prospectively for 90 days and analysed. Patients were assessed twice: at baseline and at 90 days postoperatively. Odds ratio and the corresponding 95% confidence intervals were calculated to quantify the risk. A  < 0.05 for two-tailed tests were considered significant.

Result: The 90-day mortality rate was 0.08% (all males) and 3.95% of the patients experienced one or the other complications. The majority of patients reported excellent-to-poor scores at 90-day follow-up VAS (8.85 ± 1.02 vs. 2.65 ± 1.15;  < 0.0001) and KSS scores (42.96 ± 5.90 vs. 80.52 ± 4.15;  < 0.0001). The early readmission rate was 0.96%. Infection was being the primary reason. Age > 70 years; Deyo-Charlson co-morbidity score ≥ 4, ASA grade-III, Diabetes Mellitus, BMI > 35, Cardiac Issues and Male gender were significant predictors of early morbidity and mortality. Female, Deyo-Charlson comorbidity score ≥ 4, ASA grade-III, BMI > 35, Age > 75 years and poor preoperative scores were significantly associated with poor functional outcome.

Conclusion: The present study explicates the relative importance of predictors on morbidity, mortality and functional outcome. Efforts to minimize morbidity and mortality should concentrate more on elderly male patients, and those with high Deyo-Charlson comorbidity score, BMI and ASA grade.