JOA - 2026-04-13 - Journal Article
A Novel Classification System to Predict Case Difficulty in Direct Anterior Approach Total Hip Arthroplasty.
Antonioli SS, Ruff G, Kennedy MF, Novikov D, Rozell JC, Davidovitch R
Topics
Key Takeaway
DDA grade 4 cases had significantly longer operative times than grade 1 cases (P=0.011), with the classification effect most pronounced during the learning curve phase.
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Summary
This study developed and validated the Davidovitch Direct Anterior (DDA) classification system—derived from preoperative AP pelvis radiographs—to predict case complexity in DAA THA. Multivariate regression across 283 cases showed DDA grade 4 cases had significantly longer operative times than grade 1 (P=0.011), with higher BMI (P<0.001) and cemented fixation (P=0.004) as independent predictors; 13 complications and 2 revisions occurred within 90 days. The classification's effect on operative time diminished beyond the learning curve phase.
Key Limitation
The classification was developed and validated within a single institution by only two surgeons, limiting generalizability and introducing potential center-specific bias in both technique and patient selection.
Original Abstract
INTRODUCTION
While the learning curve for direct anterior approach (DAA) total hip arthroplasty (THA) is steep, no classification exists to predict technically challenging cases. We propose and validate a new Davidovitch direct anterior (DDA) classification system for predicting DAA THA case complexity.
METHODS
We retrospectively reviewed primary DAA THAs by two fellowship-trained surgeons (October 2019 to June 2025). Exclusions included fracture, contralateral hardware, incomplete pelvis radiographs, or less than one year of follow-up. Cases were grouped into learning curve, proficient, and expert phases. Classification was based on preoperative antero-posterior (AP) pelvis radiographs. Operative time served as a proxy for case difficulty. Univariate and multivariate regressions assessed the effects of classification, surgeon experience, fixation method, and body mass index (BMI).
RESULTS
Multivariate analyses of 283 cases, including DDA classification, surgeon experience, fixation method, and BMI, demonstrated that operative times were significantly longer for DDA 4 versus DDA 1 cases (P = 0.011). Operative time decreased across learning curve, proficient, and expert phases (P < 0.001). Higher BMI (P < 0.001) and cemented fixation (P = 0.004) independently increased operative time. There were 13 overall complications and two revision THAs within 90 days.
CONCLUSION
This novel radiographic classification system predicted case difficulty in DAA THA, as DDA 4 cases took longer than DDA 1 cases, particularly during the learning curve. Beyond the learning curve, the impact of DDA classification on operative time diminished. This classification system has the potential to serve as a valuable preoperative tool for operative planning and workday efficiency, particularly for early-career surgeons on their learning curve.