Natural outcome of hemoglobin and functional recovery after the direct anterior versus the posterolateral approach for total hip arthroplasty: a randomized study

BACKGROUND: Total hip arthroplasty (THA) is one of the most successful orthopedic surgeries. There are many common surgical approaches for THA. The direct anterior approach (DAA) and posterolateral approach (PLA) were compared, leading to controversial results. METHODS: We report on a prospective randomized study which compared the changes of perioperative hemoglobin (Hb), the Harris hip score (HHS) and a visual analog scale (VAS) pain score following THA using DAA or PLA. A total of 130 participants were randomly divided into two groups (65 DAA versus 65 PLA). Perioperative ΔHb and other clinical outcomes were recorded. RESULTS: A total of 130 participants completed follow-up, while 14 patients were not recorded in blood outcomes due to blood transfusions and complications. The average Hb decrease immediately after surgery in the DAA group was greater than that in the PLA group (21.1 versus 15.8 g/L, P < .001). However, post-operative Hb descent velocity was slower in the DAA group, and the lowest point was reached earlier. No significant differences in ΔHb levels could be observed after 1 month in the two groups. When compared with the PLA group, the DAA group had a shorter incision (9.1 versus 13.5 cm, P < .001) and shorter hospital stay (4.2 versus 4.7 days, P = .004). However, the operation time of the DAA group was longer (88.0 versus 66.8 min, P < .001). The DAA group had a better HHS and VAS pain score at 6 weeks post-surgery. However, no significant differences were observed at later time points. CONCLUSION: We concluded that DAA performed better on enhanced recovery after surgery (ERAS) than PLA in THA, while both DAA and PLA could result in a positive, similar result after 3 months. TRIAL REGISTRATION: The study was registered by the Chinese Clinical Trial Registry (ChiCTR1900020770, 19 January 2019).