The Cumulative Effect of Substance Abuse Disorders and Depression on Postoperative Complications After Primary Total Knee Arthroplasty.

Background: Substance abuse disorder (SUD), alcohol abuse disorder (AUD), and depression have been identified as independent risk factors for complications after total knee arthroplasty (TKA). However, these mental health disorders are highly co-associated, and their cumulative effect on postoperative complications have not been investigated. Therefore, this study aimed to determine if patients who have more than one mental health disorder (SUD, AUD, or depression) were at an increased risk for postoperative complications following TKA.

Methods: A total of 11,403 TKA patients were identified from a prospectively collected institutional database between January 1, 2017 and April 1, 2019. Patients who had depression, SUD, and AUD were separated into 7 mental health subgroups including each of these diagnoses alone and their combined permeations. Patient demographics, body mass indices, medical comorbidities, and 15 postoperative complications were collected. Univariate analyses were performed using independent Student's t-tests. Multivariate analyses were then performed to identify odds ratios (ORs) for mental health disorders subgroups associated with complications.

Results: We found a total of 2073 (18%) patients diagnosed with either SUD (4%), AUD (0.6%), or depression (12%). Univariate analyses showed that depression was associated with mechanical failures (P < .001). SUD was associated with periprosthetic joint infection (PJI) (P < .001), wound complications (P = .022), and aseptic loosening (P = .007). AUD was associated with PJI (P < .001) and deep vein thromboses (P = .003). Multivariate analyses found that AUD (OR: 19.419, P < .001) and SUD (OR:3.693, P = .010) were independent risk factors for PJI. Compared with SUD alone, patients with depression plus SUD were found to have a 4-fold (OR: 13.639, P < .001) and 2-fold (OR:4.401, P = .021) increased risk for PJI and cellulitis, respectively.

Conclusions: Patients who had depression, SUD, or AUD were at increased risk for postoperative complications following primary TKA. When patients have more than one mental health diagnosis, their risk for complications was amplified. The results of this study can help identify those patients who are at greater risk of postoperative complications to enable improved preoperative optimization and patient education.