Pre-operative predictors of lower extremity swelling following total knee arthroplasty in patients with venous insufficiency and osteoarthritis.

PURPOSE Post-operative swelling and oedema following total knee arthroplasty (TKA) are one of the most important causes of dissatisfaction. We aimed to assess the clinical variables associated with post-operative swelling and edema after TKA and to compare their performance in respect of predicting them pre-operatively. METHODS The study cohort comprised 116 patients who underwent TKA between January 2018 and May 2019 in our centre. The diameters and the grade of venous insufficiency (VI) in the lower extremity veins were measured with duplex ultrasonography preoperatively and at one and three months post-operatively. The study cohort was divided into the patients with leg swelling positive with a difference in leg circumference of > 2 cm (n = 56, 48.2%) and leg swelling negative with a difference of ≤ 2 cm (n = 60, 51.7%) from the pre-operative leg diameter. RESULTS Independent predictors for lower extremity swelling were pre-operative great saphenous diameter (GSV) diameter > 5.5 mm [odds ratio (OR) 2.51, 95% CI 0.24-0.91; p = 0.0012], GSV reflux > 1 s [OR 3.28, 95% CI 1.16-12.1; p = 0.003], deep only VI [OR 1.32, 95% CI 0.74-1.87; p = 0.021], CEAP C4-6 [OR 1.62, 95% CI 0.36-0.91; p = 0.018], and hypothyroidism [OR 1.55, 95% CI 1.31-11.2; p = 0.031]. CONCLUSION GSV diameter of > 5.38 mm and GSV reflux duration > 1.23 s had the best predictive value for lower extremity oedema following TKA.