Direct lateral vs. posterior-lateral approach in robotic-assisted total hip arthroplasty: clinical and radiographic comparison

Introduction: The main goal of this study was to compare patient outcomes following robotic-arm assisted THA (RTHA) using the direct lateral approach (DLA) and the posterior-lateral approach (PLA) by analysing the clinical and radiographical data. Materials and Methods: 203 consecutive patients diagnosed with end stage hip osteoarthritis underwent RTHA at the same orthopaedic centre between 2015 and 2019. Patients were divided in two groups based on the surgical approach where 95 patients received PLA and 108 received DLA. All patients were assessed pre-operatively and at minimum 3-year follow-up using Harris Hip Score (HHS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). A radiographic evaluation was performed for every patient to assess the incidence of heterotopic ossification (HO). Results: Patients in the PLA cohort had higher scores in the post-operative WOMAC when compared to the DLA group (PLA: 96.2 ± 8.2 vs. DLA: 93.6 ± 10.3, p = 0.05). There was no statistical difference in the post-op HHS (PLA 86.3 ± 7 vs. DLA: 86.3 ± 9.5, p = 0.97). Accurate component positioning was achieved according to the pre-operative planning in both groups. There were no cases of dislocation. We found a significantly higher incidence of HO in the DLA group (59.3%) compared to the PLA group (12.6%). However, this difference was not associated with a poorer clinical outcome. Conclusions: Current controversy still persists regarding the surgical approach without clear evidence about which one is more appropriate. Nowadays, it seems that surgeons’ skill and experience to perform an approach are still more relevant than the choice of the approach. Both PLA and DLA represent valid surgical options for performing RTHA, yielding excellent clinical outcomes without clear evidence of superiority of one approach over the other.