Feasibility of Implantation of Cemented Femoral Stem in the Treatment of Osteoporotic Femoral Neck Fracture in Elderly Patients: a Randomized Controlled Trial

History and current related studies Femoral neck fracture is a common fracture that accounts for 3.58% of all fractures, easily occurs in the elderly with a gradually increased incidence, predisposes to bone nonunion, and greatly influences patient's mental and physical health. Bone nonunion easily occurs after femoral neck fracture because of anatomic position, biomechanical property and local blood supply. The objective of treatment of femoral neck fracture in patients aged 65 years and above is to rapidly restore lower limb function and reduce the complications caused by long term bed rest. Surgery for treatment of femoral neck fracture in the elderly is a satisfactory option because it not only contributes to recovery of joint function, but also decreases the incidence of complications. Several concerns are addressed during the process from design of internal fixation equipment to selection of clinical treatment protocol including minimizing surgical trauma, shortening length of surgery, and promoting functional recovery of hip joint. Osteoporosis is generally considered the most difficult problem to be solved after surgery for femoral neck fracture in the elderly patients. The key points of internal fixation for femoral neck fracture are to optimize bone space and strengthen fractured bone trabecula, yielding strong fixation biomechanically. Percutaneous internal fixation with cannulated compression screws has become a preferred treatment method of osteoporotic femoral neck fracture in elderly patients because of its short length of surgery and less blood loss, but insufficient holding power of used screws in the femoral neck cannot lead to strong fixation. Therefore, joint prosthesis is recommended for repair of femoral neck fracture in elderly patients. Implantation of femoral stem for treatment of early proximal femoral neck fracture has achieved confirmed clinical efficacy, but the long-term therapeutic effects in the treatment of osteoporotic fracture of proximal femoral neck remain poorly understood in patients with avascular necrosis of the femoral head.

Novelty of this study The investigators performed a search of PubMed, Web of Science and Wanfang Database up to August 2016 for articles regarding artificial prosthesis treatment of osteoporotic femoral neck fracture and found that the majority of previous reports focused on early femoral neck fracture and patients were generally followed up no more than 6 months. In this study, we will for the first time investigate the feasibility of implantation of cemented femoral stem versus percutaneous internal fixation with cannulated compression screws in the treatment of osteoporotic femoral neck fracture in the elderly patients with avascular necrosis of the femoral head necrosis through a 12 month follow up observation in terms of hip joint function, pain, histocompatibility of biomaterial with host tissue, and postoperative complications.

Data collection, management, analysis and open access An electronic data capture (EDC) system will be used for data collection and management. All study data will be in time recorded on the electronic case report form provided by the sponsor after patient's visits for recheck unless the outcomes cannot be achieved immediately. Thus, the recorded information can reflect patient's latest outcomes. Information accuracy will be rechecked after all included patients are followed up. The electronic data capture system will be locked by the project manager and will not be altered. All information relating to this trial will be preserved by Qinghai University Affiliated Hospital. The electronic data will be fully disclosed to a professional statistician for statistical analysis. Anonymized trial data will be published at http: www.figshare.com.

Statistical analysis Normally distributed continuous variables will be expressed as the mean ±SD and non-normally distributed variables will be expressed as median and quartile. Categorical variables will be expressed as counts and percentages. All data will be statistically analyzed using SPSS 19.0 software (IBM Corp., Armonk, NU, USA). Two-samples t-test or Mann-Whitney U test will be used for comparisons of Harris hip scores and VAS scores between percutaneous internal fixation with cannulated compression screws and implantation of femoral stem. The chi-square test or Fisher's exact test will be used for comparison of histocompatibility of biomaterial with host tissue. A level of P < 0.05 will be considered statistically significant.

Confidentiality Only the necessary data limited to studying the effectiveness and safety of percutaneous internal fixation with cannulated compression screws/implantation of femoral stem in the treatment of osteoporotic femoral neck fracture in the elderly patients will be collected and processed.