Individual or pooled commercial claims data sources such as the IBM MarketScan and PearlDiver provide information from health-care encounters by individuals enrolled in participating health insurance plans. These data sources contain deidentified data on demographic characteristics, enrollment start and end dates, inpatient and outpatient procedures and medical diagnoses with associated service dates and settings, and dispensed medications. Although there are concerns that long-term follow-up is limited because of interruptions in the continuity of coverage and reliance on billing data may overrecord or underrecord diagnoses and confounders, these data sources are nevertheless valuable for orthopaedic studies focusing on short-term complications, costs, and utilization.