¹Lin C, ²Qureshi I, ¹Anil U, ¹Lin L, ¹Leucht P
¹NYU Langone Orthopedic Hospital, New York, New York, United states; ²New York Institute of Technology College of Osteopathic Medicine, Mount Sinai, New York, United states

Introduction
Nonunion or malunion of fractures are complications after orthopedic trauma which often require surgical intervention. Low preoperative albumin levels have been shown to be predictive of complications after other orthopedic procedures such as total joint arthroplasty. The purpose of this study was to determine the association of hypoalbuminemia with adverse outcomes in patients undergoing surgical repair of nonunions or malunions of upper and lower extremity long bones. We aimed to compare complications, length of hospital stay and mortality within 30 days between patients with normal and low preoperative serum albumin levels.

Methods
Patients who underwent a surgical repair for nonunion or malunion of upper or lower extremity long bone fractures from 2005 to 2019 and who had preoperative serum albumin concentration levels recorded were identified from the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database. Patients were grouped into those with normal serum albumin concentrations (album >= 3.5 g/dl [n = 1,351]) and those who were hypoalbuminemic (album < 3.5 g/dl [n = 343]). Demographic variables, comorbidities and complications were collected and compared. Multivariate linear regression models were used to assess complications, adjusting for age, sex, BMI, hospital length of stay, and operation time.

Results
Patients with hypoalbuminemia had significantly increased postoperative surgical site infections, pneumonia, urinary tract infections and need for transfusions. They also had increased 30-day mortality rates, increased lengths of stay, and returns to the operating room. After adjusting for confounding variables, patients with hypoalbuminemia had significantly greater odds for any complication (OR: 2.57; 95% CI [1.74, 3.78]; p < 0.001), surgical site infections (OR: 2.66; 95% CI [1.36, 5.05]; p = 0.003) and transfusions (OR: 2.82; 95% CI: [1.64, 4.79]; p<0.001) compared to the normal albumin group.

Conclusions
There was a significant difference in 30-day postoperative complications between patients with normal albumin levels and those who were hypoalbuminemic after surgical repairs of nonunions or malunions. Albumin level is a risk factor that should be monitored and counseled upon prior to surgical intervention for nonunion or malunion correction.