A retrospective analysis of the efficacy of oral venous thromboembolism prophylaxis for patients undergoing minimally invasive direct anterior approach total hip arthroplasty

BACKGROUND: Venous thromboembolism (VTE), comprising deep vein thrombosis (DVT) and pulmonary embolism (PE), is a pertinent and preventable complication following total hip arthroplasty (THA). Direct anterior approach (DAA) THA has gained global popularity for its potential benefits; however, the optimal duration of postoperative venous VTE prophylaxis remains controversial. This study aimed to compare the efficacy of two weeks versus four weeks of rivaroxaban as postoperative VTE prophylaxis in patients undergoing minimally invasive DAA THA. METHODS: We conducted a retrospective analysis of the medical records of 526 consecutive patients who underwent elective primary THA via the DAA between 1 January 2017 and 31 December 2022. We compared the incidence of symptomatic and asymptomatic VTE, and the rate of complications associated with VTE prophylaxis within six months postoperatively in patients who received either a two- or four-week course of rivaroxaban as VTE prophylaxis following DAA THA. Duplex venous ultrasound was routinely performed at three weeks for all patients to evaluate for the presence of lower limb DVT. RESULTS: The study included 356 patients who received four weeks of treatment and 170 patients who received two weeks of rivaroxaban for postoperative VTE prophylaxis. The two groups were equally matched for age, sex, comorbidities, and preoperative vTe risk, according to the Caprini score. The overall incidence of VTE was 1% (n = 6) and included three DVTs and three pulmonary emboli (PEs). Of the DVTs detected via duplex venous ultrasound, two were diagnosed as symptomatic DVTs, and one was diagnosed as an asymptomatic DVT. The incidence of VTE was significantly greater in the two-week group than in the four-week group (p = 0.043), and all patients in whom a VTE occurred had a body mass index (BMI) of > 30 kg/m2 and a preoperative Caprini score indicating moderate or high risk. No statistically significant difference was noted in the rate of wound complications (p = 0.40) or the incidence of periprosthetic joint infections between the two cohorts (p = 0.56). CONCLUSION: A four-week course of rivaroxaban demonstrated superior efficacy in reducing the incidence of VTE compared to a two-week regimen in patients undergoing DAA THA. Importantly, the extended duration of rivaroxaban prophylaxis did not result in a significant increase in the rate of complications associated with VTE prophylaxis. These findings underscore the potential benefits of a prolonged rivaroxaban regimen for optimising postoperative VTE prevention, particularly in obese patients and high-risk patients undergoing minimally invasive DAA THA.