Acetabular component malposition during total hip Arthroplasty (THA) increases the risk of dislocation, reduces the range of motion, and can be the cause of early wear and loosening. Variability in implant alignment also affects the result of THA. The purpose of this study was to compare acetabular cup positioning of three different approaches in THA.

Three different approaches for cementless THA were studied in 108 operations.

The direct anterior approach was used in 56, the anterolateral approach in 32 and the posterolateral approach in 50. The same cementless cup was used in all cases. The same surgeon performed all procedures with mini-incision surgery, using different approaches. To determine the accuracy of the cups, the inclination and anteversion angles were measured with a CT-investigation of the pelvis.

There were no statistical differences between the three groups regarding means of the inclination and anteversion angles. But a significant range of variance, the lowest variations being in the group of the direct anterior approach, the highest in the group of the anterolateral approach.

Purpose: The interest in minimally invasive surgery (MIS) for total hip arthroplasty has not waned in anyway (THA). Different surgical approaches have been used to do MIS-THA. The purpose of this study was to compare the outcome of the THA using the minimally invasive postero-lateral approach (MIS-PL) and minimally invasive antero-lateral approach (MIS-AL).

Patients and Methods: Fifty randomly assigned patients with MIS-PL and 32 patients with MIS-AL were included in the study. There were no significant differences in age, sex, diagnosis, JOA score or body mass index in each group. The operation time, length of incision, blood loss, implant position, muscle recovery and complication were observed.

Results: Total blood loss and pain was significantly less in patients undergoing THA via MIS postero-lateral approach. In addition, the MIS-PL had improved recovery of muscle strength (hip flexion and abduction) which was statistically significant. Median cup inclination was 42.3 degrees (MIS-AL) and 41.7 degrees (MIS-PL). Median cup anteversion was 18.3 degrees (MIS-AL) and 15.9 degrees (MIS-PL), respectively. Roentgenographic evaluation of femoral component positioning showed no significant difference. Other postoperative data (length of hospital stay, operation time, complication) were comparable.

Conclusion: The MIS antero-lateral approach have often been selected to decrease the risk of dislocation, but this approach needs to release the one third of the gluteus medius from the greater trochanter. MIS postero-lateral approach caused less pain and improve recovery time, postero-lateral approach is more suitable for minimally invasive total hip arthroplasty.