Direct Anterior Approach Total Hip Arthroplasty Using a Morphometrically Optimized Femoral Stem, a Conventional Operating Table, Without Fluoroscopy

Abstract

Background: Our experience with direct anterior approach total hip arthroplasty (THA) suggests that it can be performed successfully with a morphometrically optimized metaphyseal-diaphyseal engaging femoral stem (NOT a short stem), a regular operating room table (NOT a special custom table), and WITHOUT intraoperative fluoroscopy. We report our minimum 2-year results.

Methods: A retrospective review of a single-surgeon series of primary direct anterior approach THAs was performed. All procedures were performed on a regular table, without fluoroscopy, using a cementless tapered femoral stem. Clinical, functional, and radiographic outcomes were evaluated at a minimum of 2 years.

Results: In total, 1017 primary THAs were performed. The preoperative Harris Hip Score was 40.7 ± 5.1 and improved to 95.3 ± 4.2 at minimum 2-year follow-up. There were 3 dislocations (0.3%) and 15 revisions (1.5%): 7 for infection (0.7%), 4 for periprosthetic fractures (0.4%), 2 for instability (0.2%), 1 for loosening (0.1%), and 1 for pain (0.1%). Five patients (0.5%) required blood transfusion. One patient developed deep vein thrombosis and pulmonary embolism. No intraoperative fractures, perforation, or THA-related mortality occurred. Neutral stem alignment was confirmed in 98.3%. Mean cup inclination was 38.8° ± 5.1° and anteversion was 16.2° ± 3.5°. The mean leg-length discrepancy was corrected from 1.2 ± 0.2 cm preoperatively to 0.2 ± 0.1 cm postoperatively.

Conclusion: Using a morphometrically optimized metaphyseal-diaphyseal engaging tapered femoral stem instead of a short stem reduces component malposition and minimizes risk of loosening. Combining the use of this implant design and the technique and elements described in our cohort demonstrated to have excellent results at 2 years. The patients will need continued follow-up to demonstrate further durability of this device and technique compared to others performing direct anterior THA.

Keywords: cementless tapered femoral stem; direct anterior approach; operating table; outcomes; total hip arthroplasty.