Which patient benefit most from minimally invasive direct anterior approach total hip arthroplasty in terms of perioperative blood loss? A retrospective comparative study from a cohort of patients with primary degenerative hips.

Introduction: Total hip arthroplasty (THA) is a successful surgery, but despite the advancements in anesthesiology and orthopedics, sometimes blood transfusions are required to manage the anemia due to the blood loss, involving a substantial number of patients. The aim of this retrospective comparative study is to define how the choice of the surgical approach, either direct anterior (DA) or posterolateral (PL), may influence the postoperative blood loss and the need for transfusion in THA.

Materials and methods: Data collection was carried out retrospectively of THAs performed between 2016 and 2021 on primary hip osteoarthritis treated by DA or with PL approach. Clinical and perioperative anesthetic data were collected. Preoperative hemoglobin levels were compared with the lowest detected level by calculating ΔHb (hemoglobin decrease). Then, data from the two groups were cross-checked: duration of surgery, whether premedication with tranexamic acid, duration of the hospitalization, rate of need for hemotransfusions, and amount of blood transfused. The two samples were subdivided into subgroups according to age, BMI, tranexamic acid prophylaxis, and chronic treatment with drugs that alter coagulative properties.

Results: Time of surgery was longer for patients treated with DA access (mean DA: 78.8 min; mean PL: 74.8 min; p: 0.05; 95% CI), but the length of hospitalization was shorter for patients treated with DA group with a mean time of 6.23 days versus 7.12 days for the PL group (p < 0.01). DA THA resulted advantageous mainly in patients between 66 and 75 years, showing a reduced postoperative transfusion requirement in the postoperative period (DA: 13.43%-mean: 1.33 units; PL: 26.82%-mean: 1.18 units; p: 0.044, 95% CI). Patients that assume blood-altering drugs showed a higher transfusion rate (p < 0.01), but comparison of the two subgroups showed that the choice of the surgical approach did not significantly affect the transfusion rate in these patients (p: 0.512). Prophylaxis with tranexamic acid reduced the transfusion rate (p < 0.01).

Conclusion: Patients treated by minimally invasive direct anterior approach undergo a significantly shorter hospitalization. From the analysis of patient's subgroups those aged between 66- and 75-years benefit from the DA approach mainly for the minor blood loss with less frequent transfusion requirement.