Several early reports of THA performed through the DAA demonstrated a decreased dislocation rate and quicker postoperative mobilization over the posterior approach. ^1-7 The abductor musculature is also never released, which is thought to result in a decreased rate of limping and quicker recovery compared with the lateral approach. ^8-11 Because of these benefits, the popularity of the DAA has increased in recent years; there are more surgeons performing THA through the DAA year over year and a greater number of patients requesting this approach in recent years. ¹² However, some authors have reported unique complications with the DAA and an equivalent or even increased complication rate with the DAA compared with other approaches, especially during a surgeon’s learning curve. ^{3 , 13-28} These reports have raised legitimate concerns about the appropriateness of the increasing popularity of the DAA for THA.

Most of the publications reporting outcomes of DAA THAs have small numbers, involve surgeries performed by a small number of surgeons, are retrospective, or have no comparison group. This raises questions about the external validity and generalizability of the studies. Studies with larger cohorts, those with prospectively collected data, and studies that are inclusive of many surgeons may yield a more robust perspective of outcomes with the DAA. Registry studies satisfy these criteria and are important to our growing understanding of many issues in orthopaedics. These reports show the prospectively collected results of a large number of THAs performed by numerous different surgeons with various backgrounds, increasing the power of their conclusions and generalizability compared with other studies.

As a result of the amalgamated data found in these data sets, registries are powerful tools that can be used to elucidate predictors of statistically uncommon postoperative complications, such as revisions and reoperations, as well as reasons for differences in subjective outcomes after THA (Table 49.1). ³⁷ However, registry studies do have limitations. They are retrospective studies that inherently suffer from selection bias of source inclusion, are expensive to maintain, are influenced by surgeon preferences and surgeon training, and are further limited by the data fields that the registry managers choose to collect. The purpose of this chapter is to review outcomes of DAA THA as reported by national databases.

We conducted a literature search of MEDLINE (PubMed) from which we used exploded Medical Subject Headings terms and key words to generate sets for the following themes: “Total Hip Arthroplasty” and “Surgical Approach” and “Anterior.” From here, we extracted all articles that were conducted from national databases. Additionally, we reviewed the reference lists of all included studies. All annual reports from national databases were found through an online search. Databases reporting outcomes on the DAA were included in the analysis.

The use of the DAA continues to increase worldwide. As a result, more registries are now reporting outcomes comparing DAA with other more common approaches (Table 49.2). Currently, there are only four registries reporting outcomes specifically delineating the DAA: the AOANJRR, NAR, Dutch Arthroplasty Registry, and Kaiser Permanente Registry. Registries from regions where the DAA is used but have insufficient outcome data include the American Joint Replacement Registry (AJRR), the Swedish Hip Arthroplasty Registry, the National Joint Registry of the United Kingdom, and the New Zealand Joint Registry.