Background: A flexion contracture (FC) of the proximal interphalangeal (PIP) joint can have a profound negative influence on daily activity. The outcomes of surgical release of the PIP joint in literature are based on small sample size studies done several decades ago. The aim of this study is to report the outcomes of surgical treatment for post-traumatic FC of the PIP joint and to identify factors that affect these outcomes. Methods: This single institute retrospective study included patients from 2000 to 2020. We only included patients with post-traumatic FC of the PIP joint. We evaluated the demographic characteristics, cause of FC, surgical approaches and the various procedures conducted. We surveyed postoperative complications. During the study period, we asked about their current symptoms and evaluated their operative outcomes as excellent, good, fair or poor through the phone. Results: The average FC recovery angle was 37.3°. The small finger was the most affected, and the most common cause of FC was a tendon laceration. The volar plate complex release was the most frequently conducted procedure. The FC improvement was positively correlated to the degree of preoperative FC. The more severe preoperative flexion–extension arc was presented, the more FC recovery was achieved after operation. Patients who underwent multiple procedures had a higher degree of preoperative FC, and better correction was achieved with multiple procedures than with a single procedure. The most critical complication was recurrence. Conclusions: We were able to obtain average 37.3° of extension by surgical treatment. The more severe the FC presented before surgery, the greater the need for multiple procedures, however, this resulted in a significant increase in joint extension. Nevertheless, caution should be exercised regarding recurrence and could occur even with an experienced surgeon. Level of Evidence: Level IV (Therapeutic)