Robotic-Assisted Surgery Does Not Decrease Prosthetic Impingement in Total Hip Arthroplasty: A Retrieval Analysis

Prosthetic impingement after total hip arthroplasty (THA) has been associated with instability and may be a cause of accelerated polyethylene wear and pain. Previous retrieval studies report a high prevalence of impingement in acetabular liners. Robotic technology has the potential to reduce THA instability as it enables technical precision and optimizes implant positioning. However, whether robotics can improve impingement prevalence is unknown. Thus, the objectives of this study were to: (1) determine the prevalence and severity of acetabular liner impingement with robotic navigation; and (2) compare impingement prevalence with a control cohort of manually placed THA liners.

There were 18 robotic-assisted liners and 11 non-robotic controls scored for the presence and severity of impingement. Radiographic measurements of acetabular inclination and anteversion were assessed using prerevision standing radiographs. Femoral head size (36 being the most common), length of implantation, revision indication, age, gender, and body mass index were recorded.

Of the robotic liners, 61% showed impingement, while 45% of the non-robotic liners showed impingement (P = 0.14). The robotic group demonstrated a lower variance of inclination (robotic: 41.7° ± 3.9, control: 42.8° ± 7.1, P = 0.64) and lower anteversion variance (robotic: 22.8° ± 2.8, control: 20.8° ± 7.9, P = 0.43), but mean values did not differ between the groups. Impingement presence and severity were not related to head size, length of implantation, or other demographic variables.

This study suggests that the use of robotic-assisted technology employing modern-day implants with larger diameter heads does not reduce the prevalence or severity of prosthetic impingement in retrieved acetabular liners from revision THA.