▪ PROJECT SUMMARY ▪ Metastatic bone disease afflicts the majority of patients with advanced carcinomas and is the most common oncologic disease of the skeleton. The proximal femur is the most frequently affected location in the appendicular skeleton and is a source of significant morbidity affecting patient mobility and quality of life. Stabilization of metastatic bone disease of the proximal femur has historically been achieved with internal fixation. This approach is meant to provide enough stability to ambulate without pain for the remainder of the patient’s life. However, with advances in systemic treatment options, many patients with metastatic carcinomas are experiencing significantly longer life spans. Therefore, internal fixation is increasingly resulting in devastating surgical failures and the need for revision surgery in up 20% of patients in the first year after surgery. Alternatively, complete resection of the affected bone followed by endoprosthetic reconstruction, although more invasive and conferring higher surgical risks than an internal fixation procedure, reduces the risk for implant failure to approximately 3%, and avoids the deleterious effects on function and quality of life caused by implant failure. However, at this time, the evidence supporting the use of resection and endoprosthetic reconstruction for metastatic bone disease of the proximal femur, although promising, is retrospective and methodologically weak, resulting in a gap in the necessary evidence to make this significant practice change. To address this need, we propose the Proximal FEmur Resection or Internal Fixation fOR Metastases (PERFORM) trial, which will aim to determine if resection and endoprosthetic reconstruction improves orthopaedic patient outcomes compared to internal fixation in patients with metastatic bone disease of the proximal femur. Our proposed trial planning period of two years is critical for the successful design and implementation of this potentially practice changing trial. During this planning phase, we will achieve the following three specific aims: 1) finalize the trial protocol; 2) establish the trial-specific infrastructure; and 3) determine feasibility at each clinical site and prepare relevant clinical sites for trial initiation.