Objective To summarize factors that are associated with a better treatment outcome after post-operative physical therapy in patients with shoulder arthroplasty. Data sources PubMed, Cochrane, and Web of Science. Review methods Studies examining factors that are associated with a better outcome after post-operative physical therapy interventions in patients with shoulder arthroplasty were included. Two independent reviewers performed screening, extracted data, and assessed the risk of bias and level of evidence, using the Quality In Prognosis Studies tool and Evidence-Based Guideline Development checklist. PRISMA guidelines were followed. Results In total, 460 articles were found and 14 studies were included. Two of the included articles had a moderate risk of bias, 12 high. The overall number of patients in the included studies varied from 20 to 2053. Patients had either a reverse ( N = 1863), an anatomic total shoulder arthroplasty ( N = 1029) or, a hemiarthroplasty ( N = 133). Anatomic total shoulder arthroplasty patients with a neutral rotation sling position showed less night pain and greater range of motion, which was awarded moderate evidence. Other modifiable and non-modifiable factors such as telemedicine, immediate range of motion exercises, and pre-operative function were only awarded preliminary or conflicting evidence. Conclusion Mainly preliminary and conflicting evidence was found. The possible causes of the conflicting evidence were the different measurement methods, implant types, and follow-up times used. The methodological quality was low and physical therapy protocols differed greatly. More high-quality research with standardized protocols is needed to determine the association of various factors with treatment outcomes after post-operative physical therapy in patients with shoulder arthroplasty.