The direct anterior approach for conversion to total hip arthroplasty after acetabular fixation is safe and effective.

Introduction: Total Hip Arthroplasty (THA) after prior acetabular fracture repair is known to be demanding as studies have shown inferior implant survival rates and higher infection rates for these procedures. The direct anterior (DA) approach might help mitigate some of these risks by utilizing a new surgical tissue plane. However, potential criticisms of the DA approach for these surgeries include the inability to access previous acetabular implants or heterotopic ossification (HO) if they were to inhibit implant placement. The goals of this study are to analyze the efficacy of the DA approach for conversion to hip arthroplasty surgery after previous acetabular fixation.

Methods: After reviewing all records at our institution using current procedural terminology codes, we isolated patients with previous acetabular repair who underwent conversion to THA through the DA approach. Patient records were reviewed, and patients were contacted to obtain Harris Hip Scores.

Results: 23 patients (16 males and 7 females) were found with a mean follow-up time of 46 months (range 16-156 months). The mean age was 50 (range 28 - 83) and mean BMI was 28.5 (range 15.2 - 39.2). The average blood loss was 400 ml (range 200 - 900). The average operative time was 140 min (range 85-200 min). In 7 cases (32%) implants were encountered during acetabular reaming but the implants were either removed entirely or removed partially with a burr so that the acetabular cup could be positioned within acceptable parameters. In 2 cases pre-operative HO was encountered and was resected. The average Harris Hip Score at final follow-up was 92 (range 75 - 100). There were no deep infections and no neurovascular injuries encountered. 2 patients (9%) underwent revision surgery for aseptic femoral stem loosening. There was 1 anterior dislocation (4.5%) at 3 days post-operatively that was successfully treated with closed reduction and maintenance of hip precautions. Otherwise, the remaining 19 (86%) patients went on to uncomplicated recovery.

Conclusion: This is the largest known cohort analyzing the DA approach for conversion to hip arthroplasty after previous acetabular fixation. Overall, we demonstrate that the DAA is safe for conversion THA after acetabular fixation.