Lessons from the learning curve of the direct anterior approach in total hip arthroplasty: a systematic review

The direct anterior approach (DAA) in total hip arthroplasty (THA) offers advantages in muscle preservation and early recovery but is challenged by a steep learning curve that may affect outcomes. This systematic review analyzed complication and reoperation rates during the learning phase of DAA in primary THA. A comprehensive search of PubMed, Cochrane Library, and Web of Science, was performed according to PRISMA guidelines. Studies reporting complications and reoperations during the DAA learning curve were included. Data on demographics, surgical volume, and adverse events were extracted. The primary outcomes were complication and reoperation prevalence with 95% confidence intervals (CI). Thirty-five studies encompassing 96,605 primary THAs met inclusion criteria. The overall complication prevalence during the learning curve was 2.75% (2,653/96,605; 95% CI: 2.65%-2.85%). The most frequent complications were aseptic loosening (22%), periprosthetic fracture (14%), dislocation (10%), and prosthetic joint infection (9%). The reoperation prevalence was 1.81% (1,743/96,605; 95% CI: 1.72%-1.90%), mainly due to aseptic loosening, infection, and fracture. Heterogeneity in surgeon experience and reporting limited comparability across studies. The adoption of DAA in THA is associated with a measurable learning curve characterized by increased complication and reoperation rates during early experience. Awareness of these risks, along with structured training and careful patient selection, is essential to mitigate early failures. Further prospective studies are needed to better define the learning curve threshold and standardize outcome reporting.