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. 2025 Mar 20;7(1):20.
doi: 10.1186/s42836-025-00299-x.

Cup accuracy and early-term clinical outcomes of a novel, pinless, robotic-assisted total hip arthroplasty system: A first-in-human pilot study

David Liu  1 , Atul F Kamath  2 , Jason Cholewa  3 , Luminita Stoenica  4 , Mike B Anderson  3 , Haig Lennox  5
Affiliations

Cup accuracy and early-term clinical outcomes of a novel, pinless, robotic-assisted total hip arthroplasty system: A first-in-human pilot study

David Liu et al. Arthroplasty. .

Abstract

Background: Malpositioning of the acetabular cup represents a challenge during total hip arthroplasty (THA). The purpose of this study was to evaluate the accuracy of acetabular cup placement and early postoperative clinical outcomes with a novel, pinless, fluoroscopic-guided, robotic-assisted application for direct anterior (DA) approach THA.

Methods: This prospective, pre-market phase 2 study enrolled 19 patients undergoing THA for osteoarthritis. Standing anteriorposterior (AP) and lateral radiographs up to 1 year postoperatively were assessed for component fixation and complications. Martell Hip Analysis software was used to assess radiographic acetabular anteversion and inclination from postoperative standing AP pelvis images and the results were compared to target and final component values from the surgical logs. Patient reported outcome measures (PROMs) were collected preoperatively, four weeks, three months, and one year after operation.

Results: Mean absolute difference for anteversion and inclination from respective targets on intraoperative fluoroscopic views was 1.4° ± 1.3° (P = 0.159) and 1.3° ± 1.1° (P = 0.378). The absolute difference between postoperative radiographs and intraoperative target values was 2.91 ± 2.40° (P = 0.019) for anteversion and 3.84 ± 2.57° (P = 0.007) for inclination. The difference in target and postoperative radiographic inclination and anteversion was within 5° in 77.8% of cases, and the cup was within the Lewinnek safe zone in 16 of 18. Oxford Hip Score (OHS) (44.3 ± 4.6 vs. 22.2 ± 11.3), score on Numeric Pain Rating Scale (NRPS) (0.5 ± 1.0 vs. 5.7 ± 2.6), and Hip Osteoarthritis Outcome Score-12 (HOOS-12) Overall Score (91.4 ± 11.2 vs. 42.8 ± 20.1) were significantly improved at one year. At one-year, 88.2% and 11.8% of patients were very satisfied or satisfied.

Conclusion: This first-in-human study on THA utilizing a pinless, fluoroscopy-based robotic arm demonstrated high accuracy in terms of radiographic inclination and anteversion, excellent hip-specific functional outcomes and safety one year after operation. Video Abstract.

Keywords: Acetabular cup; Arthroplasty; Direct anterior approach; Robotic; Total hip replacement.

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Conflict of interest statement

Declarations. Ethics approval and consent to participate: St John of God Health Care Human Research Ethics Committee, Project ID: 1749. All patients gave informed consent to participate after being given time to read the patient participation form and ask any questions. Consent for publication: Neither the manuscript nor any parts of its content are currently under consideration nor have been published in another journal. The manuscript is wholly original, and contributions made by the authors are listed in the title page. All authors have participated in the research and manuscript preparation and provided consent to publication of the manuscript. Competing interests: D.L. has received royalties from Zimmer Biomet, speaker honoraria from Zimmer Biomet, Depuy, LifeHealthCare, consultant honoraria from Zimmer Biomet, Depuy, has stock/stock options in Naviswiss, Formus Labs, ArthroLase, received research support from Zimmer Biomet, Depuy, Allay Therapeutics, Editorial Board for Knee Research and Related Research, Arthroplasty, and is a board member of Arthroplasty Society of Australia, Knee Arthroplasty Subspecialty Committee SICOT. A.K. has received royalties from Innomed, speaker honoraria from Zimmer Biomet, consultant honoraria from Zimmer Biomet, BodyCad, Ortho Development, United Ortho, has stock/stock options in Zimmer Biomet, and is a board member of AAOS, American Association of Hip and Knee Surgeons, Anterior Hip Foundation. J.C., L.S. and M.A. are paid employees of Zimmer Biomet and have stock/stock options in Zimmer Biomet. H.L. has received speaker and consultant honoraria from Stryker and other financial or material support from Stryker.

Figures

Fig. 1
Fig. 1
STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) flow diagram of patient inclusion into the study analysis
Fig. 2
Fig. 2
Intraoperative image intensifier radiographs of the leveled pelvis (a) and AP of hip (b) are obtained for surgical navigation with the ROSA hip system
Fig. 3
Fig. 3
Images on the C-arm monitor are captured using the ROSA tablet by the ROSA support team and then transferred to the robotic system
Fig. 4
Fig. 4
Anatomical landmarks on AP hip image required for surgical navigation and robotic arm guidance is automatically populated with surgeon verification
Fig. 5
Fig. 5
The ROSA robotic arm moves with surgeon collaboration (a) and haptic, visual and auditory feedback to the targeted inclination and version angles (b)
Fig. 6
Fig. 6
Final intraoperative cup position was validated and recorded into robotic surgical log files
Fig. 7
Fig. 7
Following final femoral component implantation, measurements of change in leg length, femoral offset and global offset are recorded
Fig. 8
Fig. 8
Scatter plot demonstrating the implants placed within the Lewinnek safe zones (red lines) according to postoperative radiographic analysis. The blue line indicates the upper limit of the Callanan safe zone for acetabular inclination. Values in degrees
See this image and copyright information in PMC

References

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