Effect of body mass index on symptomatic venous thromboembolism and prosthesis revision risk after total knee arthroplasty: a long-term study from China

Objective To investigate the effect of body mass index (BMI) on the risk of symptomatic VTE and prosthesis revision after total knee arthroplasty (TKA). Methods Seven thousand one hundred eighty-two patients with primary unilateral TKA treated in our hospital from 2011 to 2020 were divided into four groups according to BMI: BMI < 25 kg/m(2), BMI 25 kg/m(2)-29.9 kg/m(2), BMI 30 kg/m(2)-34.9 kg/m(2) and BMI >= 35 kg/m(2). Incidence, Odds ratio and Kaplan-Meier survival analysis were used to evaluate the effects of BMI on symptomatic VTE and prosthesis revision risk after TKA. Results The incidence of VTE after TKA was 8.9 parts per thousand(64/7182). There was no significant difference in the incidence of VTE among different BMI groups(P = 0.452). Deep vein thrombosis mainly occurred in the distal lower extremities, especially in intermuscular veins. Revision rate of prosthesis after TKA was 6.4 parts per thousand(46/7182). There was no significant difference in revision rate among different BMI groups(P = 0.718). In the univariate analysis of TKA, compared with patients with normal BMI, the risk of postoperative VTE and prosthesis revision in patients with overweight, obesity class I and obesity class II did not increase. Higher prosthesis revision rate and lower prosthesis survival rate were observed in BMI >= 35 kg/m(2) group, although the difference was not statistically significant. Conclusions Through such a retrospective large sample data of long-term follow-up, we believe that the higher BMI was not associated with the increased risk of symptomatic VTE and prosthesis revision after TKA. When TKA was used for appropriate indications, high BMI should not be considered as a contraindication.