Increased Incidence of Vascular Injury in Obese Patients With Knee Dislocations

Objectives: With rising rates of obesity in the United States, the burden of knee dislocations in this population remains unknown. This national epidemiologic study was designed to analyze the association of obesity with closed knee dislocation and vascular complications. Design: Retrospective cohort study. Setting: The deidentified Nationwide Inpatient Sample database was used to access the US inpatient data from 2000 to 2012. Patients/Participants: Patients with noncongenital closed knee dislocations were included. Examined variables included patient age, sex, vascular injury, and obesity status. Main Outcome Measures: Outcome measures included hospital length of stay, amputation, and inpatient hospitalization charge. Results: From 2000 to 2012, a total of 19,087 knee dislocations were identified, including 2265 in overweight/obese patients (11.9%). The annual incidence of knee dislocations reported in patients diagnosed as either obese or morbidly obese increased over the 13-year period (P < 0.0001). The overall average rate of vascular injury requiring intervention was 5.63%, whereas 7.2% of obese patients and 11.3% of morbidly obese patients with knee dislocations (P < 0.0001) sustained a vascular injury requiring intervention. The average length of stay and amputation rate for obese and morbidly obese patients who sustained a knee dislocation was not statistically different from nonobese patients when vascular injury was controlled. When patients with a vascular injury were excluded, obese and morbidly obese patients who sustained a knee dislocation had higher average cost of hospital stay than nonobese patients (P = 0.0262). Conclusions: This study demonstrates significant increases in costs of stay with obese patients sustaining knee dislocations when compared with normal weight knee dislocation patients. Vascular injuries were found to be far more common in obese and morbidly obese patient groups than nonobese patients. Providers should be on high alert when managing knee dislocations in obese patients because a significant number require prompt vascular intervention.