Abstract: Objective To investigate the clinical efficacy of total hip arthroplasty (THA) via the direct anterior approach(DAA) in elderly patients with femoral neck fractures and ipsilateral lower limb muscle weakness. Methods A total of 65 patients with weak lower limb muscle strength and femoral neck fractures admitted to the Second Affiliated Hospital of Nanjing Medical University from January 2020 to September 2025 were enrolled as study subjects. Among them, 35 patients underwent DAA-THA(observation group), and 30 patients underwent posterolateral approach total hip arthroplasty (PLA-THA, control group). Operative time, intraoperative blood loss, incision length, complication rates, and postoperative Harris Hip Score between the two groups were compared. Results All patients successfully completed the surgery and were followed up for 12 weeks. The observation group had a longer operative time, shorter incision length, and less blood loss compared to the control group, with statistically significant differences (P<0.05). In the observation group, there was only one case of hip joint posterior dislocation. In contrast, the control group had one case of surgical site infection and four cases of hip joint posterior dislocation, with no statistically significant difference (P＞0.05). The Harris Hip Scores of the observation group were higher than those of the control group 1 week, 4 weeks, and 12 weeks after operation, with statistically significant differences (P<0.05). Conclusions The DAA-THA in elderly patients with femoral neck fractures on the lower limb muscle side demonstrates favorable early outcomes, including reduced risk of prosthetic dislocation, accelerated recovery of pre-injury mobility, improved quality of life, and with high safety.

Key words: femoral neck fracture, total hip arthroplasty, direct anterior approach, posterolateral approach, lower limb muscle weakness