Complications in total shoulder and reverse total shoulder arthroplasty by body mass index.
BACKGROUND
The purpose of this study was to identify the effects of body mass index (BMI) on long-term outcomes (revision rate, 1-year mortality rate, 3-year surgical site infection rate, and 90-day inpatient all-cause readmission rate) after total shoulder arthroplasty (TSA) and reverse TSA (RTSA).


METHODS
A large shoulder arthroplasty registry was used to review outcomes after TSA and RTSA. The registry monitors patient's revision, mortality, infection, and readmission rates. The exposure of interest was the patient's BMI at the time of the surgery, which was stratified by 5 kg/m2increments.


RESULTS
Selected for this study were 4630 patients who underwent TSA and RTSA between 2007 and 2013, of which 3483 (75.2%) were TSA and 1147 (24.8%) were RTSA. The overall combined (TSA and RTSA) revision rate was 1.7%. After adjusting for confounders in the overall models (TSA and RTSA combined), higher BMI was not associated with higher risk of aseptic revision, 1-year mortality, or 3-year deep infection. In TSA-specific models, every 5 kg/m2increase in BMI was marginally associated with a 16% increase in the likelihood of 90-day readmission. This association was not observed in the RTSA model. In RTSA-specific models, every 5 kg/m2increase in BMI was marginally associated with higher risk of 3-year deep infection. This association was not observed in the TSA model.


CONCLUSIONS
Shoulder arthroplasty in obese patients is not associated with higher risk of aseptic revision. The BMI has different effects on TSA and RSA. The surgeon should anticipate increased risk of readmission after TSA and infection after RSA.
Department of Orthopaedics, Southern California Permanente Medical Group, San Diego, CA, USA.
Oke
O
Anakwenze
Department of Orthopaedics, Southern California Permanente Medical Group, San Diego, CA, USA.
Alex
A
Fokin
Department of Research & Evaluation, Kaiser Permanente Southern California, Pasadena, CA, USA.
Mary
M
Chocas
Department of Orthopedic Surgery, The Permanente Medical Group, Sacramento, CA, USA.
Mark T
MT
Dillon
Department of Orthopaedics, Southern California Permanente Medical Group, Harbor City, CA, USA.
Ronald A
RA
Navarro
Department of Orthopaedics, Southern California Permanente Medical Group, Anaheim, CA, USA.
Edward H
EH
Yian
Department of Orthopaedics, Southern California Permanente Medical Group, San Diego, CA, USA. Electronic address: Anshuman.X.Singh@kp.org.
Anshuman
A
Singh
D000368:Aged; D000369:Aged, 80 and over; D000072228:Arthroplasty, Replacement, Shoulder / Q000009:adverse effects* / Q000379:methods / Q000401:mortality; D015992:Body Mass Index; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications; D010359:Patient Readmission / Q000706:statistics & numerical data*; D012086:Reoperation / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D013530:Surgical Wound Infection / Q000453:epidemiology*
Total shoulder arthroplasty; complications; infection; obesity; reverse shoulder arthroplasty; revision shoulder arthroplasty