BACKGROUND: For elderly patients with unstable intertrochanteric fractures, hip arthroplasty is mainly applied due to the degenerative body function and difficulty in reduction.OBJECTIVE: To investigate the effectiveness and safety of cemented versus cementless hip arthroplasty for senile unstable intertrochanteric fractures.METHODS: We are conducting a prospective, single-center, non-randomized, controlled clinical trial at the Harrison International Peace Hospital, China. Eighty-six elderly patients with unstable intertrochanteric fractures were enrolled and allotted to control (n=44) and experimental (n=42) groups, followed by treated with cemented and cementless hip arthroplasty, respectively. The follow-up time is 6 months. The primary outcome is good and excellent rate according to Harris hip scores at 6 months postoperatively. The secondary outcomes are Harris hip scores and hip morphology on X-ray at 1, 3 and 6 months postoperatively, intraoperative blood loss, operation time, blood transfusion volume,time of off-bed and drainage volume at 1 month postoperatively, as well as the safety based on the incidence of adverse events at 6 months postoperatively. Partial results show that the blood transfusion volume and drainage volume postoperatively in the experimental group were significaintly higher than those in the control group (P < 0.05).There were no significant differences in the good and excellent rate according to Harris hip scores, Harris hip scores and incidence of adverse events between two groups at 6 months postoperatively (P > 0.05). There were four cases of bone cement implantation syndrome in the control group. The study protocol has been approved by the Ethics Committee of Harrison International Peace Hospital of China, approval number 2013-37. All protocols will be performed in accordance with the Ethical Principles for Medical Research Involving Human Subjects in the Declaration of Helsinki. Written informed consent was provided by each patient and their family members after they indicated that they fully understood the treatment plan.DISCUSSION: Cases were collected in January 2014 and the trial will be finished in December 2017. Cemented and cementless hip arthroplasty are mainly used to treat senile unstable intertrochanteric fractures. This study is designed to investigate the differences between cemented and cementless hip arthroplasty, thus providing referece for the treatment of unstable intertrochanteric fractures in the elderly. Partial trial results indicate that both cemented and cementless hip arthroplasties exhibit good curative efficacy and safety for senile unstable intertrochanteric fractures, while the occurrence of bone cement implantation syndrome in cemented hip arthroplasty should never be neglected.