To compare the therapeutic efficacy of total hip arthroplasty (THA) versus proximal femoral nail antirotation (PFNA) internal fixation for treating unstable intertrochanteric femur fractures (UIFF). In this retrospective study, the clinical data of 86 patients with intertrochanteric femur fractures (IFF) treated in Hangzhou Fuyang Hospital of Orthopedics of Traditional Chinese Medicine from January 2022 to December 2023 were collected and analyzed. Patients were categorized into two groups based on their treatment modality: the THA group (n=45, treated with THA) and the PFNA group (n=41, treated with PFNA internal fixation). The two groups were compared in terms of surgery-related indicators (operative time, incision length, intraoperative blood loss, postoperative drainage volume, and intraoperative fluoroscopy frequency), postoperative recovery indicators (time to first ambulation, length of stay, time until full weight-bearing ambulation), and the incidence of postoperative complications. The pain indicators (Wong-Baker Faces Pain Rating Scale) and hip joint function indicators (Harris Hip Scores) of patients in the two groups were assessed preoperatively and at 1, 3, and 6 months postoperatively. The hip joint function recovery outcomes of the two groups of patients were recorded at the last follow-up. The PFNA group had significantly shorter operative time, shorter incision length, lower intraoperative blood loss, lower postoperative drainage volume, and higher intraoperative fluoroscopy frequency compared to the THA group (all P < 0.05). The PFNA group also had significantly longer time to first ambulation, length of stay, and time until full weight-bearing ambulation (all P < 0.05). There was no statistically significant difference in the incidence of postoperative complications between the two groups (P > 0.05). Postoperative Wong-Baker scores in both groups decreased compared to preoperative levels. At 1 and 3 months postoperatively, the PFNA group had significantly higher Wong-Baker scores than the THA group (P < 0.05), but at 6 months postoperatively, the difference was not statistically significant (P > 0.05). Postoperative Harris scores increased in both groups compared to preoperative scores. At 1 month postoperatively, the PFNA group had significantly lower Harris scores than the THA group (P < 0.05); however, at 3 and 6 months postoperatively, the differences were not statistically significant (all P > 0.05). There was no significant difference in the rates of excellent recovery of hip joint function between the two groups at the last follow-up (P > 0.05). Both THA and PFNA internal fixation yield favorable outcomes in treating IFF with no significant difference in complications. The difference lies in the shorter operative time and lesser trauma inflicted by PFNA internal fixation, despite it involving prolonged radiation exposure and bed rest. Conversely, THA requires longer operative time and causes greater trauma but results in shorter postoperative recovery periods, allowing earlier ambulation.