Functional Outcome After Total Shoulder Arthroplasty in the Obese Patient Population: a Prospective Study With Greater Than 2 Years of Follow Up.

Introduction There is a high prevalence of obesity in the United States and the numbers are increasing. These patients comprise a significant portion of the shoulder arthroplasty patient population. There are several reports of outcomes in the literature on obese patients after total knee or hip replacement, however, this data is lacking in the shoulder arthroplasty patient population. The purpose of this study is to compare the functional outcomes and complications of obese patients undergoing shoulder arthroplasty with the non-obese population. Methods Between 2009 to 2010, 76 patients that had a primary total shoulder replacement were grouped according to their Body Mass Index (BMI) and followed prospectively for 2 years. The groups were divided as normal (BMI 30 BMI, N=25) according to the World Health Organization classifications. Preoperative demographics, age, comorbidities and postoperative complications were recorded. Perioperative operating room and hospital data were analyzed. Functional outcome measurements including ASES, SF-36 physical component (PC) scores, mental component (MC) scores and visual analog scale along with general health and fatigue were evaluated at the 0 and 2 year time period. Statistical analyses were performed. Results Functional outcome: In the normal BMI group: Average ASES scores improved from 38.4 +/− 15.5 (pre-op) to 80.2 +/− 19.4 (2 yr), SF-36 Physical Component (PC) scores improved from 38.3 +/− 6.5 (pre-op) to 53.7 +/− 11.3 (2 yr), and VAS decreased from 62 to 12 (2 yr). There were no intraoperative complications and two patients required revision of components. In the overweight BMI group: Average ASES scores improved from 37.4 +/− 18.1 (pre-op) to 75.2 +/− 24.9 (2 yr), SF-36 Physical Component (PC) scores improved from 36.1 +/− 8.0 (pre-op) to 39.8 +/− 12.2 (2 yr), and VAS decreased from 68 to 18. One patient had deep infection that required surgical irrigation/debridement, one intraoperative glenoid fracture converted to hemiarthroplasty and two patients required revision of components. In the obese BMI group: Average ASES scores improved from 35.8 +/− 12.5 (pre-op) to 80.0 +/− 20.6 (2 yr), SF-36 Physical Component (PC) scores improved from 36.3 +/− 8.4 (pre-op) to 40.7 +/− 12.4 (2 yr), and VAS decreased from 66 to 11 (2 yr). There were no intraoperative complications and no patients required revision surgery. * Statistical analysis showed significant difference in the SF-36 PC scores between both the overweight and the obese group compared to the normal BMI group. No statistical difference was seen between the three groups with the perioperative OR/hospital data, SF-36 MC scores, general health and fatigue scales. Conclusion Shoulder arthroplasty in all three groups were associated with significant improvements in ASES scores and decrease in overall pain. Obese and overweight patients after TSA had significantly less overall physical functional improvements compared to the normal BMI group. Both intraoperative and postoperative complications were minimal after TSA in all three BMI groups. OR time and intraoperative blood loss was higher in the obese group, but overall ASA scores and number of days of hospital stay were similar in all three groups.