The Effect of Socioeconomic Status on the Choice of Treatment for Patients With Cruciate Ligament Injuries in the Knee: A Population-Based Cohort Study

Background: The socioeconomic status (SES) of patients has been widely recognized as playing an important role in many health-related conditions, including orthopaedic conditions, in which a higher SES has been associated with a higher utilization of more advanced medical treatments such as drugs, diagnostics, and surgery. However, the association between SES and cruciate ligament surgery has not been thoroughly investigated. Purpose: To evaluate the association between SES and choice of treatment in patients with a cruciate ligament injury. Study Design: Cohort study; Level of evidence, 3. Methods: All Swedish patients with a diagnosed cruciate ligament injury between 1987 and 2010 were identified from the Swedish National Patient Register (N = 98,349). The Longitudinal Integration Database for Health Insurance and Labor Market Studies (LISA) provided information on household income and highest achieved educational level, which were used as socioeconomic indices. The exposure was the SES of patients as determined by the household income and educational level, and the main outcome measure was treatment choice (surgical reconstruction vs nonoperative treatment). Poisson regression models estimated the association. Results: A total of 52,566 patients were included in the study; of these, 20,660 (39%) were treated operatively. Patients in the highest quartile of household income had a significantly higher likelihood of undergoing surgery than those in the lowest quartile (relative risk [RR], 1.16; 95% CI, 1.11-1.20). Patients classified as highly educated had a significantly increased likelihood of being treated operatively compared with those with a low education (RR, 1.29; 95% CI, 1.19-1.39). Conclusion: This study provides a population-based validation that having a higher SES as determined by the household income and/or level of education increases the likelihood of undergoing operative treatment after a cruciate ligament injury. Clinical Relevance: All Swedish citizens are entitled by law to the same quality of health care; therefore, unmotivated differences in treatment between different socioeconomic groups are to be seen as a challenge. It is important to evaluate the specific mechanisms by which the patient's SES influences the decision of whether to treat a cruciate ligament injury operatively.