# Is direct anterior approach associated with a compromise of femoral stem survival after total hip arthroplasty? A regional registry-based analysis

## TL;DR

A study using a large regional registry found that the direct anterior approach for hip replacement does not compromise implant survival or increase the risk of loosening compared to traditional methods.

## Contribution

This study provides population-level evidence that the direct anterior approach does not negatively impact femoral stem survival in total hip arthroplasty.

## Key findings

- The 12-year cumulative survivorship for all-cause revision was similar between DAA and DL-PL approaches.
- Surgical approach was not an independent predictor of aseptic revision after adjusting for patient and implant factors.
- DAA usage increased over time, and outcomes were comparable despite differences in patient demographics and implant types.

## Abstract

The direct anterior approach (DAA) for uncemented total hip arthroplasty (THA) has been advocated for early functional recovery, yet concerns persist regarding its influence on femoral component survival. We analysed a large regional registry to compare implant survivorship and the risk of aseptic femoral loosening between DAA and conventional direct lateral/posterolateral (DL-PL) approaches.

We conducted a retrospective cohort study of 30,753 primary uncemented THAs recorded in the Emilia-Romagna Prosthetic Implant Registry (RIPO) from January 2009 through December 2021. Procedures were classified by surgical approach as DAA (n = 7,663) or DL-PL (n = 23,090). Demographic variables, implant characteristics (including stem length), and reasons for revision were extracted. Kaplan–Meier analysis estimated cumulative survivorship for any-cause revision and for revision due to aseptic loosening; group differences were assessed with the log-rank test. Multivariable Cox proportional hazards models, stratified by age (< 65 vs ≥ 65 years) and adjusted for sex and stem length, evaluated the independent effect of surgical approach on aseptic revision risk. Median follow-up was 4.6 years (IQR 2.3–7.65).

Patients undergoing DAA were slightly younger (mean 67.6 ± 10.4 vs 69.6 ± 9.8 years; p 0.001), less frequently obese (21.5% vs 28.7%; p < 0.001), and more often received short femoral stems (58.6% vs 24.8%; p < 0.001). DAA utilization increased markedly over the study period. Twelve-year cumulative survivorship for all-cause revision was high and similar between groups (DAA 95.6%, 95% CI 94.5–96.7; DL-PL 94.9%, 95% CI 94.4–95.5; log-rank p = 0.554). For aseptic loosening, 12-year survivorship was also comparable (DAA 98.9% vs DL-PL 98.4%; p = 0.562). In age-stratified adjusted Cox models, surgical approach was not an independent predictor of aseptic revision (age < 65: HR 0.81, 95% CI 0.46–1.44; age ≥ 65: HR 1.32, 95% CI 0.77–2.26).

In this large registry-based series, the DAA was not associated with inferior long-term implant survivorship or a higher risk of aseptic femoral loosening compared with DL-PL approaches after adjustment for patient and implant factors. These findings indicate that, at a population level and with appropriate case and implant selection, DAA yields mechanical outcomes comparable to traditional approaches.