Posterolateral or direct lateral approach for cemented hemiarthroplasty after femoral neck fracture (APOLLO): protocol for a multicenter randomized controlled trial with economic evaluation and natural experiment alongside

Background and purpose - The posterolateral and direct lateral surgical approach are the 2 most common surgi-cal approaches for performing a hemiarthroplasty in patients with a hip fracture. It is unknown which surgical approach is preferable in terms of (cost-)effectiveness and quality of life.Methods and analysis - We designed a multicenter randomized controlled trial (RCT) with an economic evalua-tion and a natural experiment (NE) alongside. We will include 555 patients >= 18 years with an acute femoral neck fracture. The primary outcome is patient-reported health-related qual-ity of life assessed with the EQ-5D-5L. Secondary outcomes include healthcare costs, complications, mortality, and bal-ance (including fear of falling, actual falls, and injuries due to falling). An economic evaluation will be performed for quality adjusted life years (QALYs). We will use variable block randomization stratified for hospital. For continuous outcomes, we will use linear mixed-model analysis. Dichot-omous secondary outcome measures will be analyzed using chi-square statistics and logistic regression models. Primary analyses are based on the intention-to-treat principle. Addi-tional as treated analyses will be performed to evaluate the effect of protocol deviations.Study summary - (i) Largest RCT addressing the health-related patient outcome of the main surgical approaches of hemiarthroplasty. (ii) Focus on outcomes that are important for the patient. (iii) Pragmatic and inclusive RCT with few exclusion criteria, e.g., patients with dementia can participate. (iv) Natural experiment alongside to amplify the generalizability. (v) The first study conducting a cost -utility analysis comparing both surgical approaches.