Total hip replacement performed via a direct anterior approach: A comparison of the lateral and supine position.

Background: The direct anterior approach (DA) is a recognised approach for performing a total hip replacement (THR). Proponents cite improved recovery times, lower pain levels and improved patient satisfaction in the early post operative period. The procedure can be performed in the supine or lateral position. We wanted to compare the direct anterior approach in lateral decubitus (LD) position and supine (SU) position. Methods: Single site, non-randomised, multiple surgeon retrospective cohort study between 2014 and 2021 to compare outcomes, complications and implant position for patients undergoing DAA THR in the SU or LD position. Results: A total of 39 patients (22 lateral/17 supine) were identified. Patients had an average follow up of 45 months (17-81). 95% of the cohort were ASA 1 or 2. The majority of cases were uncemented (95%). A greater implant selection was used in the lateral group and the supine group used mainly implants associated with the supine table. No significant differences were found in post operative oxford hip scores, haemoglobin, length of stay, operative time, cup inclination, offset or post operative leg length. There were no recorded intra-operative complications in the LA group and two in the SU group - one calcar fracture and one canal perforation. No patient in either group has undergone a revision procedure. Conclusion: Both the supine and lateral position have resulted in satisfactory patient and radiological outcomes. We identified a higher rate of intra-operative fracture in the supine group which is comparable with existing literature. Given the similar outcomes between both groups we would suggest that surgeons wishing to consider the DAA may consider performing this in the lateral position as this will be more familiar to them, they will be able to use their existing implants and do not need a specialised operating table.