Abstract: [Objective] To compare the clinical efficacy of proximal femoral nail anti-rotation II (PFNA-II) fixation of Evans-Jensen typeⅡto type R femoral intertrochanteric fractures in lateral position versus supine counterpart. [Methods] A retrospectve research was conducted on 306 patients who had Evans-Jensen type II to type R femoral intertrochanteric fractures fixed with PFNA-Ⅱ in Ruikang Hospital from January 2017 to December 2022. According to the preoperative doctor-patient communication, 166 patients had PFNA performed in lateral position (LP), while the remaining 140 patients were in supine position (SP). The documents regarding perioperative period, follow-up and images were compared between the two groups. [Results] All patients in both groups had PFNA performed smoothly without intraoperative complications. The LP group proved significantly superior to the SP group in terms of operation time [(88.4±19.4) min vs (97.9±22.4) min, P<0.001], total incision length [(6.9±2.0) cm vs (7.5±1.9) cm, P=0.004], intraoperative blood loss [(107.4±40.1) mL vs (121.3±41.9) mL, P=0.003], and intraoperative fluoroscopy times [(13.5±0.8) vs (15.0±1.2), P<0.001], despite of the fact that there were no significant differences in incision healing grade, hospital stay and ambulation time between the two groups (P>0.05). The follow-up period lasted for (15.2±1.6) months in a mean, and there was no a significant difference in the time to resume full weight-bearing activity between the two groups (P>0.05). Compared with those 6 months after surgery, the VAS, Harris scores, as well as hip flexion-extension range of motion (ROM) and hip internal-external rotation ROM were significantly improved in both groups 12 months after surgery (P<0.05). At 6 and 12 months after operation, the LP group achieved significantly greater flexion-extension ROM [(99.0±7.4)° vs (96.5±8.9)°, P=0.010; (114.2±9.1)° vs (111.4±9.3)°, P=0.010] and internal-external rotation ROM [(49.9±7.9)° vs (47.0±8.4)°, P=0.020; (56.0±7.9)° vs (52.7±8.3)°, P< 0.001] than the SP group. Regarding imaging, there was no any statistically significant differences in terms of Baumgaertner's fracture reduction grade, and femoral neck-shaft angle (FNSA), tip apex distance (TAD) and fracture healing time between the two groups (P>0.05). [Conclusion] The lateral position takes the advantages of convenient operation, shorter operation time and less bleeding for PFNA-Ⅱ fixation of femoral intertrochanteric fractures over the supine position