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Randomized Controlled Trial
. 2025 Jul;33(7):2571-2580.
doi: 10.1002/ksa.12644. Epub 2025 Mar 10.

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

Omer M Farhan-Alanie  1 , James Doonan  1 , Philip J Rowe  2 , Matthew S Banger  2 , Bryn G Jones  1 , Angus D MacLean  1 , Mark J G Blyth  1
Affiliations
Randomized Controlled Trial

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

Omer M Farhan-Alanie et al. Knee Surg Sports Traumatol Arthrosc. 2025 Jul.

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.

Level of evidence: Level I.

Keywords: bi‐unicompartmental; knee arthroplasty; randomised controlled trial; survivorship.

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References

REFERENCES

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