Objective:To compare the efficacy of proximal femoral nail antirotation (PFNA) with metaphyseal expansion or non-expansion in the treatment of femoral intertrochanteric fracture in the elderly.Methods:A retrospective cohort study was conducted to analyze the clinical data of 349 elderly patients with femoral intertrochanteric fracture, comprising 168 males and 181 females, aged 60-84 years [(73.5±8.6)years]. According to AO fracture classification, 108 patients were classified as type A1, 164 type A2, and 77 type A3. Of them, 168 patients received PFNA with metaphyseal expansion (expansion group), while 181 received PFNA with metaphyseal non-expansion (non-expansion group). The operation time, intraoperative blood loss, recessive blood loss, postoperative drainage volume, total blood loss, intraoperative blood transfusion rate and length of hospital stay were compared between the two groups. Visual analogue scale (VAS) scores preoperatively, at 2 and 6 weeks postoperatively of the two groups were detected. The neck-shaft angle and tip-apex distance were measured preoperatively, immediately after surgery, and at 6 months postoperatively. Harris hip score was evaluated at 1, 3, and 6 months postoperatively. Additionally, time to weight-bearing ambulation, fracture healing time, and postoperative complication rate were compared between the two groups.Results:All the patients were followed up for 6-10 months [(7.8±1.2)months]. The operation time for the expansion group was (69.6±12.4)minutes, significantly longer than (65.3±11.5)minutes of the non-expansion group ( P<0.01). Intraoperative blood loss, recessive blood loss, postoperative drainage volume and total blood loss were (124.8±16.9)ml, (684.1±95.3)ml, (123.9±25.1)ml and (932.8±125.4)ml respectively, which were more than those of the non-expansion group [(96.3±12.6)ml, (623.4±87.4)ml, (110.6±29.7)ml, and (830.3±112.6)ml] ( P<0.01). The intraoperative blood transfusion rate was 50.0% (84/168), higher than 38.1% (69/181) of the non-expansion group ( P<0.05). There was no significant difference in the length of hospital stay between the two groups ( P>0.05). There was no significant difference in VAS scores between the two groups before surgery, at 2 and 6 weeks after surgery ( P>0.05). The VAS scores of the two groups at 2 and 6 weeks after surgery were lower than those before surgery, and there were significantly lower scores at 6 weeks after surgery when compared with those at 2 weeks after surgery ( P<0.05). There were no significant differences in neck-shaft angle and tip-apex distance of the two groups before surgery, immediately after surgery and at 6 months after surgery ( P>0.05). In both groups, the neck-shaft angle immediately after surgery and at 6 months after surgery decreased while the apex distance increased when compared with those before surgery ( P<0.05). Furthermore, significantly lower neck-shaft angle and larger apex distance were observed at 6 months after surgery when compared with those immediately after surgery ( P<0.05). There was no significant difference in Harris hip scores at 1, 3 and 6 months after surgery between the two groups ( P>0.05). In both groups, the Harris hip scores at 3 and 6 months after surgery were higher than those at 1 month after surgery ( P<0.05) and the Harris hip scores at 6 months after surgery were higher than that those at 3 months after surgery ( P<0.05). There were no significant differences in time to weight-bearing ambulation, fracture healing time and total postoperative complication rate between the two groups ( P>0.05). Conclusions:For the elderly patients with femoral intertrochanteric fractures, PFNA with proximal metaphyseal expansion or non-expansion is equally effective in shortening hospital stay, relieving pain, improving reduction quality, promoting hip function recovery and reducing complication rate. However, PFNA with non-expansion treatment can shorten the operation time, reduce intraoperative blood loss, recessive blood loss, postoperative drainage volume and total blood loss, and lower intraoperative blood transfusion rate.