A Nationwide Analysis on the Impact of Schizophrenia Following Primary Total Knee Arthroplasty: A Matched-Control Analysis of 49,176 Medicare Patients.

Background: The influence of schizophrenia on total knee arthroplasty (TKA) is limited in the literature. Therefore, the purpose of this study was to investigate whether patients with schizophrenia undergoing primary TKA have (1) longer in-hospital length of stay (LOS); (2) higher readmission rates; (3) higher medical complications; (4) higher implant-related complications; and (5) higher costs of care compared to controls.

Methods: Patients with schizophrenia undergoing primary TKA were identified within the Medicare claims database. The study group was randomly matched in a 1:5 ratio to controls according to age, sex, and medical comorbidities. The query yielded 49,176 patients with (n = 8,196) and without (n = 40,980) schizophrenia undergoing primary TKA. Primary outcomes analyzed included in-hospital LOS, 90-day readmission rates, 90-day medical complications, 2-year implant-related complications, in addition to day of surgery and 90-day costs of care. A P-value less than .01 was considered statistically significant.

Results: Schizophrenia patients had longer in-hospital LOS (3.73 days vs 3.22 days, P < .0001) and had higher incidence and odds ratios (ORs) of readmission rates (18.26 vs 12.07%; OR: 1.58, P < .0001) compared to controls. Schizophrenia patients had higher incidence and odds of medical (3.23 vs 1.10%; OR: 2.99, P < .0001) and implant-related complications (5.92 vs 3.59%; OR: 1.68, P < .0001) and incurred significantly higher day of surgery ($13,300.58 vs $11,681.77, P < .0001) and 90-day costs of care ($18,222.18 vs $14,845.64, P < .0001).

Conclusion: This study demonstrates that patients with schizophrenia have longer in-hospital LOS, higher readmission rates, higher complications, and increased costs of care after primary TKA.