Comparing cup placement, leg length, and offset discrepancy after total hip arthroplasty between CT-based robotic arm-assisted and navigation systems
2025

Comparing Robotic Arm-Assisted and Navigation Systems in Hip Surgery

Sample size: 74 publication 10 minutes Evidence: high

Author Information

Author(s): Shimizu Akira MD, PhD, Murakami Satoshi MD, Tamai Takayuki MD, Haga Yuuki MD, Kutsuna Tatsuhiko MD, PhD, Kinoshita Tomofumi MD, PhD, Takao Masaki MD, PhD

Primary Institution: Ozu Memorial Hospital, Ozu, Japan

Hypothesis

Does a CT-based robotic arm-assisted system improve cup placement accuracy and reduce leg length discrepancies compared to a CT-based navigation system?

Conclusion

Robotic arm-assisted total hip arthroplasty is more accurate in cup orientation and position than navigation-based methods, effectively reducing postoperative leg length and offset discrepancies.

Supporting Evidence

  • Robotic arm-assisted surgery showed significantly smaller absolute differences in cup orientation compared to navigation surgery.
  • Postoperative leg length discrepancies were significantly lower in the robotic arm-assisted group.
  • More hips in the robotic arm-assisted group had global offset discrepancies within 5 mm compared to the navigation group.

Takeaway

Using a robot to help with hip surgery makes it easier for doctors to place the hip joint correctly, which helps patients have fewer problems with leg length and joint position after surgery.

Methodology

The study involved 60 hips from 54 patients undergoing robotic arm-assisted surgery and 45 hips from 44 patients undergoing navigation surgery, with postoperative measurements taken using CT.

Potential Biases

Case selection bias may still be present despite propensity score matching.

Limitations

The sample size was relatively small, and the study was not a randomized controlled trial, which may introduce selection bias.

Participant Demographics

Patients included those with primary osteoarthritis or secondary osteoarthritis due to developmental dysplasia of the hip, with a mean age of approximately 69 years.

Statistical Information

P-Value

p = 0.002 for RI, p = 0.005 for ΔRI, p = 0.042 for SI

Statistical Significance

p<0.05

Digital Object Identifier (DOI)

10.1302/2633-1462.61.BJO-2024-0173.R1

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