Comparison Study of Patient Demographics, Risk Factors, and Lengths of Stay for Postoperative Ileus After Primary Total Knee Arthroplasty

Background: Postoperative ileus is a potential complication after orthopedic surgery, which has not been well studied after total knee arthroplasty (TKA). The aims of this study were to analyze rates of postoperative ileus; patient demographic profiles; in-hospital lengths of stay (LOS); and patient-related risk factors for postoperative ileus after primary TKA. Methods: A query was performed from January 1, 2005 to March 31, 2014 using the Medicare Standard Analytical Files. Patients who underwent primary TKA and developed postoperative ileus within 3 days after their index procedure were identified. Patients who did not develop ileus represented controls. Primary outcomes analyzed and compared included patient demographics, risk factors, and in-hospital LOS. A P value less than .05 was considered statistically significant. Results: Ileus patients were older, more likely to be male, and had higher Elixhauser-Comorbidity Index scores (8 vs 6; P < .0001) compared with controls. Male patients (odds ratio [OR], 2.12; P < .0001), patients with preoperative electrolyte/fluid imbalance (OR, 3.40; P < .001), patients older than 70 years (OR, 1.62-2.33; P < .015), and body mass indices greater than 30 kg/m² (OR, 1.79-2.00; P < .001) were at the greatest risk of developing ileus. In addition, ileus patients had significantly longer in-hospital LOS (5.42 vs 3.22 days; P < .001). Conclusion: The study demonstrated differences in patient demographics, patient-related risk factors, and an increased in-hospital LOS for ileus patients after primary TKA. The study is important as it can allow orthopedists to properly identify and optimize patients with certain risk factors to potentially mitigate this adverse event from occurring.