A Simple Clinical Grading of Complexity Based on Local and Systemic Factors Demonstrates Pre-Operative Differences, Longer Operative Times, and Length of Stay in a Total Knee Replacement Patient Cohort

Background: A 4-part grading system was developed and used to better stratify knee arthroplasty patients, based on presence or absence of systemic and local (site of surgery) factors with defined parameters. The 4 groups are: 1) C0 (Complexity Nil) patients having no local or systemic complexity. 2) C1 (Complex Local) patients having local site of surgery complexity but no systemic complexity. 3) C2 (Complex Systemic) patients having systemic complexity but no local complexity. 4) C3 (Complex Local & Systemic) patients having both local and systemic complexity. Methods: A cohort of consecutive primary knee arthroplasty patients were graded pre-operatively. Operative time, length of stay in hospital, 42-day readmission and 90-day mortality were key measured outcomes. Results: Of 1943 patients, group proportions were: C0 44%, C1 25%, C2 20%, C3 11%. There were statistically significant differences in demographics, operative times, length of hospital stays and 90-day mortality between groups. Combined local and systemic complexity (C3) patients demonstrated the poorest outcomes of all groups with statistical significance. Conclusions: This grading methodology shows differences in demography, total operating time and lengths of stay between groups. It shows summative interaction between local and systemic factors impacting operative performance, currently overlooked by many health systems and registries. The results have implications for patient information, resource allocation, case-mix assessment and economics. It establishes the case for further investigation of patient outcomes and application to other procedures and formal validation.