BACKGROUND: Financial responsibility may impact patient outcomes after total knee arthroplasty (TKA). This study investigated whether a patient's out-of-pocket spending after TKA would affect their utilization of postoperative services. METHODS: The retrospective study identified 13,173 patients undergoing primary TKA and their associated billing claims between 2019 and 2021. Patients who underwent bilateral TKA or other orthopaedic procedures during the study period were excluded. Medicare patients were compared to private insurance and further grouped into "high" or "low" out-of-pocket spenders. To determine ( cutoff values for "high" and "low" spending, a 75/25 split was used in which 75% of the data creates a normal distribution, while 25% of the data is skewed. The primary outcome was the utilization of services after TKA. RESULTS: Medicare patients who were "high" spenders (+) had the same number of physical therapy visits, X-rays, and in-office procedures as the "low" spenders. Privately insured patients who were "high" spenders (96+) also had similar postoperative service utilization as the "low" spenders, aside from attending fewer physical therapy sessions after TKA (12.8 versus 14.1, P = 0.02). Privately insured "low" spenders had higher postoperative complication rates (6.6 versus 4.1%, P = 0.002). CONCLUSIONS: In this study, TKA patients had similar utilization of postoperative services, regardless of out-of-pocket expenses. Privately insured low spenders demonstrated longer length of stay and increased complication rates, although patient comorbidities are likely to contribute. Future research is warranted on the role of financial responsibility in orthopaedic patient care.