• BACKGROUND
    • The surgical approach impacts the outcomes and recovery after total hip arthroplasty (THA), and approaches may affect the stem positioning. Contrary to the general concept of minimally invasive surgery, the direct anterior approach (DAA) results in more intraoperative blood loss. Therefore, the objective of this study was to compare stem positioning and hidden blood loss (HBL) among three surgical approaches: the minimally invasive DAA, Orthopadische Chirurgie Munchen (OCM), and the traditional posterolateral approach (PLA).
  • METHODS
    • A total of 201 patients undergoing their first non-cemented THA using the DAA, OCM, and PLA were included in the study. General demographic data, stem alignment, and blood loss were evaluated. Specific comparison measurements included femoral neck anteversion, femoral stem anteversion, alignment of the stem in coronal and sagittal planes, proximal and distal medullary ratios, and femoral offset. Blood loss was measured by calculating Intraoperative Blood Loss ( IBL), visible blood loss (VBL), and hidden blood loss (HBL).
  • RESULTS
    • There were no significant differences in age, gender, body mass index, preoperative diagnosis, or femoral Dorr classification among the three groups. The mean surgical time was longer for the DAA and OCM compared to the PLA (P < 0.01). IBL was highest in the DAA group and lowest in the PLA (P < 0.05). Postoperative stem anteversion were significantly different among the groups, with the DAA showing the greatest anteversion difference (P < 0.05). There was no difference in the stem coronal alignment. However, there were more valgus and varus implants in the sagittal plane for the DAA and OCM. The femoral offset reduction was less optimal in the DAA and OCM groups (P < 0.05). The proximal and distal medullary ratios were lower in the DAA and OCM (P < 0.05). HBL was significantly lower in the DAA and OCM compared to the PLA (P < 0.05).
  • CONCLUSION
    • Minimally invasive approaches such as DAA and OCM offer advantages in muscle and soft tissue preservation, leading to reduced HBL compared to the conventional PLA. However, these approaches present challenges in femoral stem positioning and longer surgical times.