Proceeding from direct lateral to anterolateral approach in total hip arthroplasty: A closer look on radiological and clinical aspects

Anterolateral approach may be superior to posterolateral approach in controlling postoperative lower limb discrepancy in primary total hip arthroplasty: A single-center, retrospective cohort study

OBJECTIVES

This study aims to investigate the possible association and comparison between anterolateral approach (ALA) and posterolateral approach (PLA) and postoperative lower limb discrepancy (LLD) in selective total hip arthroplasty (THA).

PATIENTS AND METHODS

April 2021 and July 2021, a total of 266 consecutive patients (126 males, 140 females; mean age: 46.7±13.6 years; range, 22 to 60 years) who underwent unilateral primary THA via the ALA or the PLA were retrospectively analyzed. The operations were performed by a single surgical team. All patients were divided into two groups according to the approach: ALA group (n=66) and PLA group (n=200). Relevant data were recorded. Diagnosis including hip osteoarthritis, developmental dysplasia of the hip (DDH), aseptic avascular necrosis (AVN), and inflammatory arthritis were noted. Perioperative follow-up radiographs were evaluated and measured to compare the postoperative LLD and offset. The association between two approaches and postoperative LLD and offset was analyzed using the univariate and multivariate linear regression analysis.

RESULTS

The mean follow-up was 20±3.7 (range, 16 to 25) months. Univariate analysis revealed that the postoperative LLD, the postoperative acetabular offset, and hospital costs were lower in the ALA group than the PLA group (p<0.01). However, the offset and length of stay were comparable between the two groups (p>0.05). Multivariate analysis revealed that the PLA (β=4.71; 95% confidence interval [CI]: 1.78 to 7.64), preoperative LLD (β=0.29; 95% CI: 0.21 to 0.37), DDH (β=5.01; 95% CI: 1.47 to 8.55), and AVN (β=3.81; 95% CI: 0.50 to 7.12) were the main contributors to the postoperative LLD.

CONCLUSION

Our study results suggest that the ALA may be superior to the PLA in controlling the postoperative LLD among some of the selective unilateral primary THA patients. Both the ALA and the PLA were comparable in terms of the restoration of offset.

Cementless total hip arthroplasty with anatomic-shaped implants. Does the minimal invasive anterolateral technique influence the stem position or subsidence in contrast to the standard lateral approach?

INTRODUCTION

Using cementless stems in total hip arthroplasty (THA) has revealed variable results. The risk for early aseptic loosening has been associated to certain surgical approaches and implant designs. This study determines misalignment of collared/collarless stems and the rate of subsidence using the anterolateral approach (ALA) compared to implantations via the direct lateral approach (DLA).

MATERIALS AND METHODS

One hundred consecutive patients underwent primary unilateral THA using the minimal invasive ALA in the lateral decubitus position and were compared to another cohort of 100 patients, treated trough the DLA. Clinical results were noted preoperatively and after 1 year using the WOMAC score. The radiographic evaluation included the stem alignment and subsidence.

RESULTS

Overall, all patients improved in WOMAC from 48.9 points (± 11.4; 21.0-82.0) to 3.1 (± 3.2; 0.0-22.0) (p < 0.001). For DLA and ALA, the stem was placed on average 2.5° in varus to the femoral axis. The mean alignment was about 0.5° more valgus for collarless stems. The mean subsidence in the DLA group was about 0.3 mm higher compared to the ALA group. With collarless implants, the subsidence was about 1.0 mm higher compared to collared implants (p < 0.05), especially in patients with Dorr type B femurs.

CONCLUSIONS

Changing from the DLA to the minimal invasive ALA did not significantly affect the implant position. Misalignment and a potential risk for early aseptic loosening could not be seen. The use of a collared cementless stem seems safe and is likely to prevent a relevant subsidence, even more so in Dorr type B femurs.

LEVEL OF EVIDENCE

III.