Summary

Exclusively mechanical prophylaxis with an unilateral portable intermittent pneumatic compression device reduces leg and ankle edema and also blood loss in the postoperative period of total knee arthroplasty, when compared to exclusively pharmacological prophylaxis with enoxaparin

Abstract

This is a randomized clinical trial aiming to evaluate edema in the operated lower limb and blood loss after total knee arthroplasty (TKA) in patients undergoing two methods of thromboprophylaxis: pharmacological (enoxaparin) compared with mechanical (a portable intermittent pneumatic compression device, IPCD). We included 150 adult patients who underwent unilateral primary TKA for any cause; we did not include those with a previous or family history of venous thromboembolism (deep venous thrombosis or pulmonary embolism), coagulation disorders, previous liver disease or body mass index higher than 40 kg/m2, as well as those undergoing bilateral surgery. Patients who missed follow- up visits were excluded. All were operated by the same technique with posteriorly stabilized prosthesis, without replacement of the patella, by the same main surgeon. They were randomized into two groups: group E, whose prophylaxis was exclusively pharmacological, with 40 mg of enoxaparin for 10 days, started 12 h after the end of surgery; and group M, with exclusively mechanical prophylaxis, using a portable IPCD continuously, only at the operated side and below the knee, from the end of surgery until the 10th postoperative (PO) day. Patients began walking on the same day of surgery, at an average of six hours postoperatively in both groups. Edema was assessed by measuring the circumference of the thigh, leg and ankle, between the preoperative period and the third PO day. Blood loss was evaluated by the volume of the suction drain output in 48 h and by the variation in the hemoglobin (Hb) and hematocrit (Ht) rates between the preoperative period and the second PO day. After hospital discharge, the participants were followed up in three consultations (10, 45 and 90 days of PO). Five patients were excluded because they did not attend follow- up visits (three in group E and two in M). Edema was greater in patients in group E than in group M at the three measured sites: thigh, leg and ankle, but this variation was statistically significant only in the leg (p = 0.002) and ankle (p < 0.001). Regarding blood loss, the drain volume was statistically higher in group E (p < 0.001), as well as the drop in Hb (p = 0.001) and Ht (p = 0.001). Based on the results of this study, we concluded that exclusively mechanical prophylaxis with a portable unilateral IPCD reduces leg and ankle edema and also blood loss in the postoperative period of TKA, when compared to exclusively pharmacological prophylaxis with enoxaparin.