Comparison of Postoperative Instability and Acetabular Cup Positioning in Robotic Assisted versus Traditional Total Hip Arthroplasty
Shaw JH, Rahman TM, Wesemann LD, Jiang C, Darrith B, and Davis JJ. Comparison of Postoperative Instability and Acetabular Cup Positioning in Robotic Assisted versus Traditional Total Hip Arthroplasty. J Arthroplasty 2022.
The Journal of arthroplasty
BACKGROUND: Robotic-assisted total hip arthroplasty (R-THA) affords precision yet uncertain clinical benefits. This study compares dislocation rates and related revisions between R-THA and manual total hip arthroplasty (M-THA). Secondarily we evaluated cup position, patient-reported outcome measures (PROMs), and postoperative complications.
METHODS: A three-surgeon cohort study was conducted on 2,247 consecutive patients (1724 M-THA and 523 R-THA) who received a primary THA between January 2014 and June 2020 at a single hospital. Demographics, PROMs, emergency department visits, readmissions, and 90-day complications were collected via the Michigan Arthroplasty Registry Collaborative Quality Initiative. Chart review yielded instability occurrence with average follow-up of 4 years. Multivariate regression analysis was performed and a sample of 368 radiographs including all dislocations were assessed.
RESULTS: There were significantly lower rates of dislocation in R-THA (0.6%) versus M-THA (2.5%; Multivariate odds ratio 3.74, p < .046). All cases of unstable R-THA were successfully treated conservatively, whereas 46% of unstable M-THA were revised for recurrent instability. Cup anteversion (25.6° ± 5.4° R-THA vs. 20.6° ± 7.6° M-THA) was greater and cup inclination (42.5° ± 5.3° R-THA vs. 47.0° ± 6.7° M-THA) was lower in the R-THA group (p < .05). No significant differences were noted for demographics, PROMs, or other complications (p > .05).
CONCLUSION: R-THA resulted in less than one-fourth the dislocation rate compared to M-THA and no revision for instability. It was associated with no difference in PROMs or other early complications. The influence of R-THA on stability goes beyond simply cup positioning and deserves further study.
ePub ahead of print