BACKGROUND: The goal of bundled payments-lump monetary sums designed to cover the full set of services needed to provide care for a condition or medical event-is to provide a reimbursement structure that incentivizes improved value for patients. There is concern that such a payment mechanism may lead to patient screening and denying or providing orthopaedic care to patients based on the number and severity of comorbid conditions present associated with complications after surgery. Currently, however, there is no clear consensus about whether such an association exists. QUESTIONS/PURPOSES: In this systematic review, we asked: (1) Is the implementation of a bundled payment model associated with a change in the sociodemographic characteristics of patients undergoing an orthopaedic procedure? (2) Is the implementation of a bundled payment model associated with a change in the comorbidities and/or case-complexity characteristics of patients undergoing an orthopaedic procedure? (3) Is the implementation of a bundled payment model associated with a change in the recent use of healthcare resources characteristics of patients undergoing an orthopaedic procedure? METHODS: This systematic review was registered in PROSPERO before data collection (CRD42020189416). Our systematic review included scientific manuscripts published in MEDLINE, Embase, Web of Science, Econlit, Policyfile, and Google Scholar through March 2020. Of the 30 studies undergoing full-text review, 20 were excluded because they did not evaluate the outcome of interest (patient selection) (n = 8); were editorial, commentary, or review articles (n = 5); did not evaluate the appropriate intervention (introduction of a bundled payment program) (n = 4); or assessed the wrong patient population (not orthopaedic surgery patients) (n = 3). This led to 10 studies included in this systematic review. For each study, patient factors analyzed in the included studies were grouped into the following three categories: sociodemographics, comorbidities and/or case complexity, or recent use of healthcare resources characteristics. Next, each patient factor falling into one of these three categories was examined to evaluate for changes from before to after implementation of a bundled payment initiative. In most cases, studies utilized a difference-in-difference (DID) statistical technique to assess for changes. Determination of whether the bundled payment initiative required mandatory participation or not was also noted. Scientific quality using the Adapted Newcastle-Ottawa Scale had a median (range) score of 8 (7 to 8; highest possible score: 9), and the quality of the total body of evidence for each patient characteristic group was found to be low using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) tool. We could not assess the likelihood of publication using funnel plots because of the variation of patient factors analyzed in each study and the heterogeneity of data precluded a meta-analysis. RESULTS: Of the nine included studies that reported on the sociodemographic characteristics of patients selected for care, seven showed no change with the implementation of bundled payments, and two demonstrated a difference. Most notably, the studies identified a decrease in the percentage of patients undergoing an orthopaedic operative intervention who were dual-eligible (range DID estimate -0.4% [95% CI -0.75% to -0.1%]; p < 0.05 to DID estimate -1.0% [95% CI -1.7% to -0.2%]; p = 0.01), which means they qualified for both Medicare and Medicaid insurance coverage. Of the 10 included studies that reported on comorbidities and case-complexity characteristics, six reported no change in such characteristics with the implementation of bundled payments, and four studies noted differences. Most notably, one study showed a decrease in the number of treated patients with disabilities (DID estimate -0.6% [95% CI -0.97% to -0.18%]; p < 0.05) compared with before bundled payment implementation, while another demonstrated a lower number of Elixhauser comorbidities for those treated as part of a bundled payment program (before: score of 0-1 in 63.6%, 2-3 in 27.9%, > 3 in 8.5% versus after: score of 0-1 in 50.1%, 2-3 in 38.7%, > 3 in 11.2%; p = 0.033). Of the three included studies that reported on the recent use of healthcare resources of patients, one study found no difference in the use of healthcare resources with the implementation of bundled payments, and two studies did find differences. Both studies found a decrease in patients undergoing operative management who recently received care at a skilled nursing facility (range DID estimate -0.50% [95% CI -1.0% to 0.0%]; p = 0.04 to DID estimate: -0.53% [95% CI -0.96% to -0.10%]; p = 0.01), while one of the studies also found a decrease in patients undergoing operative management who recently received care at an acute care hospital (DID estimate -0.8% [95% CI -1.6% to -0.1%]; p = 0.03) or as part of home healthcare (DID estimate -1.3% [95% CI -2.0% to -0.6%]; p < 0.001). CONCLUSION: In six of 10 studies in which differences in patient characteristics were detected among those undergoing operative orthopaedic intervention once a bundled payment program was initiated, the effect was found to be minimal (approximately 1% or less). However, our findings still suggest some level of adverse patient selection, potentially worsening health inequities when considered on a large scale. It is also possible that our findings reflect better care, whereby the financial incentives lead to fewer patients with a high risk of complications undergoing surgical intervention and vice versa for patients with a low risk of complications postoperatively. However, this is a fine line, and it may also be that patients with a high risk of complications postoperatively are not being offered surgery enough, while patients at low risk of complications postoperatively are being offered surgery too frequently. Evaluation of the longer-term effect of these preliminary bundled payment programs on patient selection is warranted to determine whether adverse patient selection changes over time as health systems and orthopaedic surgeons become accustomed to such reimbursement models.