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Novel Classification System to Predict Case Difficulty in Direct Anterior Approach Total Hip Arthroplasty.
Sophia S Antonioli1, Garrett Ruff1, Mitchell F Kennedy1
1Department of Orthopedic Surgery, NYU Langone Health, New York, New York.
The Journal of Arthroplasty
|April 15, 2026
Summary
A new Davidovitch direct anterior (DDA) classification system helps predict direct anterior approach (DAA) total hip arthroplasty (THA) case complexity. This radiographic tool aids surgeons, especially those early in their learning curve, in planning and improving efficiency.
Area of Science:
- Orthopedic Surgery
- Surgical Technique Innovation
Background:
- Direct anterior approach (DAA) total hip arthroplasty (THA) presents a steep learning curve.
- A need exists for a classification system to predict challenging DAA THA cases.
Purpose of the Study:
- To propose and validate the Davidovitch direct anterior (DDA) classification system.
- To assess the DDA classification's ability to predict case complexity in DAA THA.
Main Methods:
- Retrospective review of 283 primary DAA THAs performed by fellowship-trained surgeons.
- Classification based on preoperative anteroposterior pelvis radiographs.
- Operative time used as a proxy for case difficulty, analyzed with multivariate regression.
Main Results:
- The DDA classification significantly impacted operative time, with DDA 4 cases taking longer than DDA 1 cases (P = 0.011).
- Operative times decreased across learning curve, proficient, and expert phases (P < 0.001).
- Higher BMI and cemented fixation independently increased operative time.
Conclusions:
- The novel DDA classification system effectively predicts DAA THA case difficulty, especially during the learning curve.
- The classification's impact on operative time diminishes beyond the initial learning phase.
- The DDA classification system offers potential as a preoperative tool for planning and efficiency, particularly for early-career surgeons.

