As you have pointed out, patients contemplating shoulder replacement surgery who happen to be significantly overweight may have some special needs. The use of tobacco in any form adds even more risk. The presence of vascular (blood flow) problems often present in obese adults and anyone who smokes can increase your risk of complications during and after surgery. Poor wound healing and infection are common problems but life-threatening blood clots, heart attack, stroke, and even death have also been reported.
Traditional anatomic total shoulder replacements can be used to aid in reducing pain and improving motion and function in overweight and obese patients. But when compared with adults who are not overweight or obese (and who also receive an anatomic total shoulder replacement), results are definitely not as good. The obese patient is more likely to have problems and complications and less likely to be happy with the results.
A different type of implant has been developed that is being considered for use with obese adults who need a shoulder replacement. This alternate replacement device is called a reverse total shoulder arthroplasty (RTSA). This implant reverses the socket and the ball, placing the ball portion of the shoulder where the socket used to be and the socket where the ball or humeral head used to be.
This new design provides a much more stable shoulder joint and its use is NOT contraindicated for obese adults. But according to the authors of a recent study investigating the results of the reverse shoulder replacement, patients should be warned of the high complication rate, especially for the risk of infection. Of course, they can also expect the same improvements in motion and reductions in pain obtained by nonobese patients. Time will tell if other changes (positive or negative) will occur in the long-term results.