Epidemiology of Multiligament Knee Reconstruction

The multiple-ligament-injured knee represents a special challenge, being an uncommon injury that is both severe and complicated to treat. Many studies have evaluated patients treated for this injury, but most are limited in their scope. The evaluation of this injury and its treatment using an administrative database might provide a different perspective. Using a large administrative database, we determined (1) the number of multiligament knee reconstructions in New York State, (2) the rate of 90-day hospital readmission, and (3) the frequency of subsequent knee surgery. We examined the rates of these outcomes as a function of diagnosis, admission type, discharge status, comorbidity burden, and patient demographic factors. We used the New York Department of Health Statewide Planning and Research Cooperative System (SPARCS), a database with information on patient characteristics, diagnoses, and treatments, to identify patients who underwent a multiligament procedure in a nonfederal facility from 1997 to 2005 using ICD-9-CM and Current Procedural Terminology codes. SPARCS collects data from all nonfederal acute care facilities, with an estimated reporting completeness of almost 99% for the years in this study. We evaluated data on patient age, sex, admission type, discharge status, and comorbidity burden (using Elixhauser comorbidities) and developed a multivariable logistic regression model to assess the influence of confounding variables. We identified 1032 patients in this database who underwent multiligament knee reconstruction in New York State from 1997 to 2005. The frequency of readmission within 90 days was 4.8% (n = 49). Readmission was more likely for patients who underwent inpatient multiligament reconstruction (odds ratio [OR] = 2.3; 95% CI: 1.2-4.4; p = 0.014), had a diagnosis of dislocation (OR = 2.2; 95% CI: 1.2-3.9; p = 0.011), or had various Elixhauser comorbidities, including chronic lung disease (OR = 6.4; 95% CI: 1.5-27.2; p = 0.013), fluid and electrolyte disorders (OR = 19.7; 95% CI: 2.5-155.7; p = 0.005), and anemia deficiency (OR = 5.6; 95% CI: 1.05-29.4; p = 0.044). Two hundred eighty-seven patients (28%) underwent subsequent knee surgery between their index procedure and 2006. Subsequent surgery was more likely for patients who underwent inpatient multiligament reconstruction (OR = 1.4; 95% CI: 1.1-1.9; p = 0.011) or were readmitted within 90 days of the index surgery (OR = 4.2; 95% CI: 2.3-7.6; p < 0.001). Our findings have the potential to aid clinicians in identifying their patients with multiligament reconstruction at highest risk for 90-day readmission and subsequent knee surgery. Future research, particularly large prospective studies evaluating surgical approaches and timing, will be critical in advancing the treatment of multiligament knee injuries.