Does surgical approach influence implant positioning in total hip arthroplasty? A radiological comparison of direct anterior and posterolateral approaches.

BACKGROUND

Total Hip Arthroplasty (THA) is one of the most frequently performed orthopaedic procedures worldwide. The direct anterior approach (DA) is increasingly utilised as a minimally invasive, muscle-sparing technique that allows quicker recovery. However, concerns remain regarding component positioning due to the limited access to the acetabulum and femur, particularly in the absence of robotic assistance. This study aimed to compare radiological parameters of implant positioning in conventional THA performed via DA and the posterolateral approach (PL).

METHODS

A retrospective case-control study was conducted on 100 patients (50 DA, 50 PL) who underwent primary THA for end-stage osteoarthritis or avascular necrosis. All procedures were performed by a single surgeon experienced in both approaches. Postoperative radiographs were assessed by two independent, blinded observers for acetabular inclination, anteversion, femoral offset, and limb length discrepancy (LLD). Statistical analysis was performed using an unpaired Student's t-test and Mann-Whitney U test, with p < 0.05 considered significant.

RESULTS

The mean acetabular inclination was 42.7° ± 3.1° in the DA group and 40.2° ± 4.7° in the PL group (p = 0.045). Mean anteversion (16.3° ± 3.9° vs. 16.8° ± 3.3°, p = 0.895) and LLD (10.7 mm ± 11.1 vs. 9.5 mm ± 7.6, p = 0.703) showed no significant difference. No periprosthetic fractures or LFCN injuries were noted in the DA group.

CONCLUSION

Implant positioning in the DA can be comparable to that achieved with the posterior approach when performed by an experienced surgeon. The use of intraoperative fluoroscopy in DA provides an added advantage. As a minimally invasive, muscle-sparing technique with proven early functional benefits and comparable radiological parameters, the DA represents a reliable option for primary THA.