In a study of 15,288 patients who underwent shoulder arthroplasty it was found that the complication rate was very low. Dangers exist like with every surgery but based on this study from UCLA the complications are minimal. The study was published in the
J Shoulder Elbow Surg. 2011 Feb 14 by the Department of Orthopaedic Surgery, University of California-Los Angeles, Los Angeles, CA, USA. I am attaching the results and conclusion section of the paper:
RESULTS:
During the study period, 15,288 patients underwent shoulder arthroplasty. Patients undergoing total shoulder arthroplasty and hemiarthroplasty had no statistically significant difference in the aggregate risk of 90-day complications or the risk of implant failure within the study period. Fracture patients were shown to have a higher risk of short-term complications (odds ratio, 3.2; P < .001). Implant failure rates were lower in patients with fracture, rheumatoid arthritis, increased comorbidity, and advanced age.
CONCLUSION:
This study reports similar rates of short-term complications and implant failure in patients undergoing total or hemiarthroplasty, an overall mortality rate of 1.3%, and a pulmonary embolism rate of 0.6%. The findings of our study indicate that the risk of short-term complications is highest in patients undergoing total or hemiarthroplasty for a fracture compared with nonfracture indications. Our results also indicate that longer-term, implant survival is largely driven by factors associated with increased activity, such as age. In patients undergoing surgery for arthritis of the shoulder, we found no difference in implant survival rates between total and hemiarthroplasty of the shoulder.