Background: Shared decision-making is an approach to making treatment-based decisions that rely on the patient encounter and clear discussions between the patient and the healthcare provider. Patients with arthritis of the knee frequently seek care, and depending on arthritis severity and impact on daily life, joint arthroplasty may be considered as a treatment option. We will conduct a systematic review of shared decision-making trials in knee arthroplasty to determine the types of shared decision-making approaches used and their impact on care received. Methods: Our systematic review will describe and critically appraise shared decision approaches used in randomized trials of patients undergoing knee arthroplasty, the types of outcomes reported, and the impact of these approaches on the patients' care. We will use the following databases: PubMed, Web of Science, Embase, CINAHL, PsycINFO, and the Cochrane Library, from inception through December 2018. Additionally, we will assess ongoing research by querying experts and searching trial registries. Discussion: This study will characterize shared decision-making (SDM) approaches in knee arthroplasty randomized clinical trials and will summarize their effects of SDM on clinical and patient-reported outcomes. We anticipate this review will bring to light knowledge gaps and inform further research into the design and use of shared decision-making approaches in lower extremity arthroplasty.