Comparable Outcomes After Total Knee Arthroplasty in Medicaid and Commercially Insured Patients at a High-Volume Institution.

BACKGROUND

Reported data remains mixed on the extent to which insurer status as a surrogate for socioeconomic status (SES) affects perioperative outcomes in patients undergoing total knee arthroplasty (TKA).

PURPOSE: This study evaluated postoperative outcomes utilizing insurance status as a surrogate for SES.

METHODS

This study retrospectively reviewed 8961 patients undergoing primary TKA at a single institution. Patients were grouped by insurance: Medicaid or non-Medicare commercial insurance. The primary outcome measure was revision surgery within 5 years of the index TKA. Time-to-event outcomes including reoperation, readmission, manipulation under anesthesia (MUA), and patient-reported outcome measures (PROMs) were analyzed.

RESULTS

Kaplan-Meier survival curves revealed greater time to revision survival probability in patients with Medicaid compared to patients with commercial insurance. No statistically significant differences were observed between groups for reoperation-free survival, readmission-free survival, or MUA-free survival. At both 1-year and 2-year postoperative follow-up, commercially insured patients had statistically significantly higher Knee Injury and Osteoarthritis Outcome Score Jr (KOOS Jr) scores compared with Medicaid patients. However, the absolute differences in KOOS JR scores at these time points did not exceed the previously established minimal clinically important difference.

CONCLUSION

Despite having increased comorbidities and higher body mass index, Medicaid patients treated at this high-volume institution had improved revision-free survival and no difference in rates of reoperation or readmission, while achieving similar PROMs during the first 2 years following TKA.

LEVEL OF EVIDENCE: Level III, Prognostic study.