One hundred fifty-eight patients with osteoarthritis and a BMI greater than 30 were randomized to receive either patient-specific instrumentation (PSI; n=80) or standard of care (SOC; n=78) for primary total knee arthroplasty (TKA). The outcomes of interest included the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, the Short Form 12 survey (SF-12), Knee Society Score (KSS), and rates of adverse events. Outcomes were assessed at baseline, 6 weeks, 3, 6, and 9 months, 1 year, and 5 years postoperatively. Overall, the results of the study revealed no significant differences in patient-reported outcomes, function, or adverse events between the PSI and SOC groups at 5 years. The study suggests that PSI does not provide additional benefits over SOC in this patient population.