X-ray Analysis to Assess the Difference in the Accuracy of Components Placement in THA Surgeries between Different Surgical Approaches

Background:
Total hip arthroplasty (THA) is performed in 3 surgical approaches in our institution - Direct anterior (DA) , Antero-lateral (AL) and Posterior (POS). While DA approach is performed with intraoperative fluoroscopy, the other approaches are not. Therefore, The research hypothesis was that in the direct anterior approach the surgeon achieves greater accuracy in placing the implants components and restoring the normal hip biomechanics.

Methods:
We performed a retrospective X-ray analysis of patients who underwent THA between 2014 and 2019 at Sheba Medical Center in the three different approaches: DA, AL and POS.. The following radiologic parameters were assessed:

- Ilioischial offset.

- Medial offset.

- Femoral offset.

- LLD.

- Inclination.

- Anteversion.

- COR

- Stem alignment

Results:

210 patients were included in the study: 91 (41.33%) had DA approach, 41 (19.52%) POS approach and 78 (37.14%) AL approach. In the POS approach there was an increased anteversion relatively to the other approaches (28 (±9) degrees compared with 23 (±6) and 17(±6) degrees in the DA and the AL approaches, in concordance (p<0.001)). No significant differences were found in the other measurements.

In addition, the data shows that in the 3 approaches, the surgeons were able to preserve the normal hip biomechanics.

LLD- DA 0 (±4) mm, POS +1 (±6) mm, AL +1 (±6) mm. P=0.737.

Femoral offset- DA +1 (±7) mm, POS +2 (±10) mm, AL +2 (±7) mm. P=0.592.

Conclusions:
In THA surgeries in anterior approach using intraoperative X-ray versus posterior and anterolateral approaches no difference was observed in the accuracy of components placement or in maintaining the biomechanics of the hip joint, a difference was observed only in the degree of anteversion which was increased in the posterior approach group.