Prospective, randomised controlled trial comparing robotic arm‐assisted bi‐unicompartmental knee arthroplasty to total knee arthroplasty

Farhan‐Alanie, Omer M. and Doonan, James and Rowe, Philip J. and Banger, Matthew S. and Jones, Bryn G. and MacLean, Angus D. and Blyth, Mark J. G. (2025) Prospective, randomised controlled trial comparing robotic arm‐assisted bi‐unicompartmental knee arthroplasty to total knee arthroplasty. Knee Surgery, Sports Traumatology, Arthroscopy. ISSN 1433-7347 (https://doi.org/10.1002/ksa.12644)

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Abstract

Purpose: The objective of this study was to compare the clinical outcomes 2 years following surgery between robotic-arm assisted bi-unicompartmental knee arthroplasty (bi-UKA) compared with conventional mechanically aligned total knee arthroplasty (TKA). Methods: This is a single-centre, double-blinded, randomised controlled trial comparing bi-UKA and TKA. Patient-reported outcome measures (PROMs) were collected from 60 patients (27 bi-UKA and 33 TKA patients) 2 years following surgery, including Oxford Knee Score (OKS), New Knee Society Score (NKSS), Forgotten Joint Score, EQ-5D-3L, UCLA activity scale, Hospital Anxiety and Depression Scale, Pain and Stiffness Visual Analogue Scales, Satisfaction and Range of Motion. Complications were also recorded at each visit. Results: TKA and bi-UKA continue to offer comparable PROMs. The clinical NKSS demonstrated a significant difference between the two interventions, TKA 59.5 (37–65) versus bi-UKA 26.0 (22–40) (p < 0.001). There were no significant differences shown between the interventions across all time points and remaining outcome measures (OKS at 2-year follow-up; TKA—42.0 [34.0–45.5] vs. bi-UKA—41.0 [28.0–45.0]) or the proportion of participant achieving bi-phasic gait at 2 years following surgery (p = 0.429). There was no difference in complication rates following surgery at 2 years. Conclusion: Robotic arm-assisted, cruciate-sparing bi-UKA and mechanically aligned TKA offer similar clinical outcomes 2 years following surgery with no difference in complication rates. Further, follow-up is required to monitor patients as they enter mid/long-term follow-up and determine whether patients will gain long-term benefits from the cruciate-sparing bi-UKA approach.

ORCID iDs

Farhan‐Alanie, Omer M., Doonan, James, Rowe, Philip J. ORCID logoORCID: https://orcid.org/0000-0002-4877-8466, Banger, Matthew S., Jones, Bryn G., MacLean, Angus D. and Blyth, Mark J. G.;