Background: The time frame in which patients can expect functional improvement after open reduction internal fixation (ORIF) of pilon fractures is unclear. The purpose of this study was to determine the trajectory and rate at which patients’ physical function improves up to 2 years postinjury. Methods: The patients studied sustained a unilateral, isolated pilon fractures (AO/OTA 43B/C) and followed at a level 1 trauma center over a 5-year period (2015-2020). Patient-Reported Outcomes Measurement Information Systems (PROMIS) Physical Function (PF) scores from these patients at defined follow-up times of immediately, 6 weeks, 3 months, 6 months, 1 year, and 2 years after surgery defined the cohorts and were retrospectively studied. Results: There were 160 patients with PROMIS scores immediately postoperatively, 143 patients at 6 weeks, 146 patients at 12 weeks, 97 at 24 weeks, 84 at 1 year, and 45 at 2 years postoperatively. The average PROMIS PF score was 28 immediately postoperatively, 30 at 6 weeks, 36 at 3 months, 40 at 6 months, 41 at 1 year, and 39 at 2 years. There was a significant difference between PROMIS PF scores between 6 weeks and 3 months ( P < .001), and between 3 and 6 months ( P < .001). Otherwise, no significant differences were detected between consecutive time points. Conclusion: Patients with isolated pilon fractures demonstrate the majority of their improvement in terms of physical function between 6 weeks and 6 months postoperatively. No significant difference was detected in PF scores after 6 months postoperatively up to 2 years. Furthermore, the mean PROMIS PF score of patients 2 years after recovery was approximately 1 SD below the population average. This information is helpful in counseling patients and setting expectations for recovery after pilon fractures. Level of Evidence: Level III, prognostic.