Abstract:[Objective] To compare the clinical efficacy of Intertan Nail (IN) versus Proximal Femoral Nail Anti-rotation (PFNA) in thetreatment of unstable intertrochanteric femur fracture (IFF) in the elderly. [Methods] A total of 114 elderly patients with unstable IFF weretreated by operation from January 2019 to December 2021. The patients were divided into 58 cases in the IN group and 56 cases in the PF-NA group by random number method. Perioperative, follow-up and imaging data were compared between the two groups. [Results] The PF-NA group proved significantly superior to the IN group in terms of operation time [(45.3±8.0 min) vs (49.6±7.9) min, P<0.05], the total inci-sion length [(4.5±1.2) cm vs (5.0±1.3) cm, P<0.05], blood loss [(81.7±10.3) ml vs (127.6±20.0) ml, P<0.05], intraoperative fluoroscopy times[(11.7±2.4) times vs (13.0±2.2) times, P<0.05], ambulation time [(6.5±1.2) days vs (7.6±1.4) days, P<0.05], incision healing time [(12.0±2.3) days vs (13.4±3.1) days, P<0.05] and hospital stay [(5.9±0.9) days vs (7.1±1.3) days, P<0.05], despite of insignificant difference in clini-cal fracture healing time between the two groups (P>0.05). Compared with those 6 months after surgery, the Harris score, hip extension-flex-ion ROM and internal-external rotation ROM significantly increased in both groups at 12 months after surgery (P<0.05), whereas whichwere not statistically significant between the two groups at any time points accordingly (P>0.05). Radiographically, there were no significantdifferences in the quality of fracture reduction and fracture healing between the two groups (P>0.05). In addition, there were no statisticallysignificant differences in shaft-neck angle and anteversion between the two groups at any time points accordingly (P>0.05). However, theIN group had significantly less tip-apex distance (TAD) than the PFNA group at the last follow-up [(23.4±2.5) mm vs (25.2±2.8) mm, P<0.05]. [Conclusion] Both IN and PFNA used for internal fixation of unstable IFF do restore hip function and promote fracture healing in the elderly. By comparison, the PFNA is more suitable for elderly patients with poor tolerance due to less intraoperative blood loss, fluoroscopytimes, short operation time and hospital stay, while IN takes better biomechanical advantages.