To evaluate the association between preoperative hypoalbuminemia and length of stay in patients undergoing primary knee or hip arthroplasty.

From August 2017 to January 2019, 253 male and 640 female patients who underwent primary knee or hip arthroplasty were enrolled in this retrospective study. The patients with incomplete information, perioperative serious complications for specific treatment, bilateral arthroplasty, revision surgery, and hemophiliac arthritis were excluded. The age ranged from 19 to 95 years old. There were 492 cases of primary knee arthroplasty and 401 cases of primary hip arthroplasty. The patients were divided into the hypoproteinemia and normal group according to the serum albumin level. The lengths of total, preoperative and postoperative hospital stay of the two groups were recorded. The preoperative morbidities, perioperative blood transfusion rate, and postoperative complications in the two groups were recorded. The quantitative data between the two groups were evaluated by Mann-Whitney U test. The chi-square test was used to analyze the difference of gender, type of joint replacement, concomitant diseases, and postoperative complications between the two groups. Multivariate linear regression was used to analyze the factors affecting the length of stay. The association between hypoproteinemia and increase of length of stay was analyzed.

The total incidence of hypoproteinemia was 43.6%.There was no statistically significant difference in gender, age, or joint replacement type between the two groups (P>0.05). The total, preoperative, and postoperative lengths of stay in the hypoproteinemia group were significantly longer than those in the normal group [(11.5±4.0) d vs (10.5±3.9)d, U=78 375, P<0.001; (5.1±2.6)d vs (4.8±2.4)d, U=88 193, P<0.01; (6.4±2.8)d vs (5.7±2.8)d, U=76 023, , P<0.001]. The patients in hypoproteinemia group had a significantly higher proportion of hypertension, cerebral thrombosis and surgical history. There was no statistically significant difference in blood transfusion rate and postoperative complications between the two groups(all P>0.05). Multiple regression analysis showed that age, knee arthroplasty, history of cerebral thrombosis and hypoproteinemia were significantly correlated with length of stay.

Preoperative hypoproteinemia could significantly increase the length of stay in patients undergoing primary knee or hip arthroplasty.