When robotic-assisted and manual total hip arthroplasty (THA) square off, which one shines? That was the question in the minds of a team from Michigan when they set out to compare dislocation rates and revisions between these two approaches.
Robotic-Assisted THA vs Manual THA, Which Wins?
The study, “Comparison of Postoperative Instability and Acetabular Cup Positioning in Robotic-Assisted Versus Traditional Total Hip Arthroplasty,” appears in the February 1, 2022 edition of The Journal of Arthroplasty.
“Dislocation remains one of the most common reasons for revision surgery,” senior author Jason Davis, M.D., an adult reconstruction surgeon at Henry Ford Hospital in Detroit, Michigan, told OTW. “While now robotic technology can assist with accurately preparing bone and placing an implant, little has been published with larger numbers of patients and real-life outcomes a few years out.”
To compare robotic-assist with manual THA, the research team examined 2,247 consecutive patients (manual: 1,724 and robotic: 523) each of whom were treated with a primary THA between January 2014 and June 2020 at one institution.
Robotic-assisted THA resulted in significantly lower rates of dislocation as compared to THA (0.6% and 2.5%, respectively). “All cases of unstable robotic-assisted THA were successfully treated conservatively, whereas 46% of unstable manual THA were revised for recurrent instability. Cup anteversion was greater, and cup inclination was lower in the robotic-assisted THA group. No significant differences were noted for demographics, patient-reported outcome measures, or other complications,” wrote the authors.
“We found a several fold decrease in dislocation rates and no revisions for instability,” commented Dr. Davis to OTW. “Of the 20 manual hips that required revision for this issue, the dislocation incidence is actually much higher as many dislocate three times before requiring further surgery. A brief look at our cup positioning found acceptable results in both groups, highlighting the multifactorial nature of instability and that robotics may help surgical variables beyond simply positioning.”
“In this era of value-based medicine, while the upfront costs of robotics are higher, the downstream savings in ER visits and surgeries in this example may illustrate savings to hospital systems and payors that want to see the improved outcomes their patients care about.”

Discussion
This is a fascinating development. In my practice we've seen similar outcomes with the revised protocol. The key differentiator seems to be patient selection criteria. Has anyone else noticed the correlation with BMI thresholds?
Great point. I'd push back slightly on the conclusion, the sample size in the cited study is too small to draw population-level inferences. That said, the directional signal is compelling and worth a larger RCT.
We implemented a similar approach last year. Early results are promising but we're still gathering 12-month follow-up data. Happy to share our protocol if anyone is interested.
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