Background: Total hip replacement with a collum femoris preserving (CFP) short stem prosthesis can reportedly reduce postoperativecomplications and preserve maximum bone tissue for long-term revision. However, CFP replacement has a relatively high risk of intraoperative periprosthetic fractures that can seriously harm hip function recovery. Therefore, this study aims to analyze risk factors for periprosthetic fractures and develop preventive measures to reduce postoperative complications.Methods/Design: A prospective, single-center, self-controlled, open-label study with 2-year follow-up will be carried out at the Department of Orthopedics, Third Hospital of Hebei Medical University, Shijiazhuang, Hebei Province, China. We will analyze data from 25 patients who undergo total hip replacement with the CFP prosthesis. Primary outcome measure is Harris hip score preoperativelyand 6, 12, and 24 months postoperatively. Secondary outcome measures include fracture severity as assessed by periprosthetic fracture classification according to the American Academy of Orthopaedic Surgeons guidelines, and bone healing as assessed by CT and radiographic findings preoperatively and 6, 12, and 24 months postoperatively, including parameters of the proximal and mesal medullary cavity of the fractured femur (width of the medullary cavity at the point 20 mm above the midpoint of the small trochanter, at the midpoint of the small trochanter, at the point 20 mm below the midpoint of the small trochanter, and at the fracture line; width of the corresponding prostheses), intertrochanteric width, femoral neck-stem angle, femoral neck anteversion, femoral neck length, ratio of the distal end of the prosthesis to the medullary space, and height of the femoral calcar. Other outcome measures are multiple logistic regression analysis results of risk factors for periprosthetic fracture during hip replacement, and the incidence of adverse events within 24 months postoperatively.Discussion: This study will be expected to provide references for reducing the incidence of periprosthetic fracture during hip replacementwith the CFP prosthesis.Trial registration: ClinicalTrials.gov identifier: NCT02981823.Ethics: Approved by the Ethics Committee of the Third Hospital of Hebei Medical University, China (approval number: KE2016-011-1), the study protocol will be performed in accordance with the guidelines of the Declaration of Helsinki, formulated by the World Medical Association.Informed consent: Written informed consent will be obtained from all participants prior to the trial.doi: 10.4103/2542-4157.194809How to cite this article: Qin D, Han YT, Li HJ (2017) Effect of periprosthetic fracture on hip function after femoral neck-preserving total hip arthroplasty: study protocol for a prospective, single-center, self-controlled trial with 2-year follow-up. Clin Trials Orthop Dis 2(1):24-30.