Background: Obesity is increasingly prevalent in the United States. There are several reports of outcomes in obese patients after total knee or hip replacement. The purpose of this study was to compare the functional outcomes and complications of obese patients undergoing shoulder arthroplasty with those of overweight or normal-weight patients.
Methods: Seventy-six patients who underwent primary total shoulder arthroplasty were grouped according to body mass index. The groups were classified as: normal, which was denoted by a body mass index of <25 kg/m2 (twenty-six patients); overweight, which was denoted by a body mass index of 25 to 29.9 kg/m2 (twenty-five patients); and obese, which was denoted by a body mass index of ≥30 kg/m2 (twenty-five patients). Preoperative demographics and perioperative and postoperative complications were recorded. The American Shoulder and Elbow Surgeons score, Short Form-36, and visual analog scale pain and fatigue scores were evaluated at baseline and at the two-year follow-up visit.
Results: In the normal group, the mean scores (and standard deviation) improved for the American Shoulder and Elbow Surgeons score from 38.4 ± 15.5 points preoperatively to 80.2 ± 19.4 points at two years postoperatively (p < 0.001) and for the Short Form-36 Physical Component Summary score from 38.3 ± 6.5 points preoperatively to 53.7 ± 11.3 points at two years postoperatively (p < 0.001); the visual analog scale pain scores decreased from a mean score of 62 points preoperatively to 12 points at two years postoperatively (p < 0.001). In the overweight group, the mean scores (and standard deviation) improved for the American Shoulder and Elbow Surgeons score from 37.4 ± 18.1 points preoperatively to 75.2 ± 24.9 points at two years postoperatively (p < 0.001) and for the Short Form-36 Physical Component Summary score from 36.1 ± 8.0 points preoperatively to 39.8 ± 12.2 points at two years postoperatively (p = 0.21); the visual analog scale pain scores decreased from 68 points to 18 points (p < 0.001). In the obese group, the mean scores (and standard deviation) improved for the American Shoulder and Elbow Surgeons score from 35.8 ± 12.5 points preoperatively to 80.0 ± 20.6 points at two years postoperatively (p < 0.001) and for the Short Form-36 Physical Component Summary score from 36.3 ± 8.4 points preoperatively to 40.7 ± 12.4 points at two years postoperatively (p = 0.15); the visual analog scale pain scores decreased from 66 points preoperatively to 11 points at two years postoperatively (p < 0.001). There was one deep infection in the overweight group that required surgical irrigation and debridement. Two revisions of the components were required in the normal group.
Conclusions: Obesity did not have a detrimental effect on the improvement of short-term shoulder function. However, the overall physical function of obese and overweight patients does not significantly improve after total shoulder arthroplasty. In the normal body mass index group, patients did improve overall physical function after total shoulder arthroplasty.
Level of evidence: Prognostic level II. See Instructions for Authors for a complete description of levels of evidence.