Study on the learning curve during the transition from direct lateral to direct anterior approach in total hip arthroplasty : a consecutive one hundred and twenty-seven case series

Abstract Background: Direct anterior approach (DAA) for primary hip arthroplasty has received increasing attention recently. However, there have been no reports focused on the learning curve when transitioning from direct lateral approach(DLA) to DAA. This study evaluates a single surgeon’s learning curve by examining Procedure Time (PT), Operation Preparation Time (OPT), Operating Room Time(ORT) and other data. Methods: From 2019 to 2021, a single surgeon’s first 100 cases with DAA and 27 cases with DLA between the learning cure were reviewed. PT, OPT, ORT and other data were analyzed. Results: Compared with DLA, PT, OPT and ORT had a sharp rise in the first 10 cases. There was no statistical significance in PT after 20 cases, ORT after 30 cases, and OPT after 50 cases. The difference of PT and ORT between group 1(DLA) and group 2(DAA, 1-51 cases), group 2 and group 3(DAA, 51-100 cases) were statistically significant. OPT of Group 1 was the shortest, increased significantly in group 2, gradually decreased in group 3. There were significant differences in blood lossbetween group 1 and group 3, between group 2 and group 3. 4 complications in total, 1 case in group 1, 3 cases in group 2. There were no significant differences in blood transfusion, length of stay and complication rate. Conclusions: When transitioning from DLA to DAA, an experienced surgeon may be low efficient, with longer PT, OPT and ORT. Great changes appeared after DAA 50 cases, complications and blood loss could be controlled within the safe range.