BJJ - 2026-09-01 - Journal Article; Randomized Controlled Trial; Comparative Study
A prospective double-blinded randomized controlled trial comparing conventional jig-based versus robotic arm-assisted medial unicompartmental knee arthroplasty.
Kayani B, Fontalis A, Tahmassebi J, Konan S, Plastow R, Wazir U, Shah M, Oussedik S, Haddad FS
Topics
Key Takeaway
Robotic-arm-assisted medial UKA achieved superior component position accuracy (p<0.001 for both femoral and tibial components) and higher Forgotten Joint Scores at 2 years compared to conventional jig-based UKA, though standard PROMs (OKS, KOOS, WOMAC) did not differ.
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Summary
This double-blinded RCT randomized 107 patients with symptomatic medial compartment OA to CT-planned conventional jig-based versus robotic-arm-assisted Oxford-style medial UKA. RO UKA demonstrated superior femoral and tibial component position accuracy (p<0.001), reduced inpatient opioid consumption (p=0.008), shorter hospital stay (p=0.004), and higher Forgotten Joint Scores at 6 months (p=0.002) and 2 years (p=0.021). OKS, KOOS, and WOMAC scores were equivalent between groups at 2-year follow-up.
Key Limitation
This is an interim analysis of an incomplete trial with recruitment compromised by patient preference and surgeon equipoise loss, making it underpowered to detect differences in revision rates or long-term implant survivorship.
Original Abstract
AIMS
This study reports the interim outcomes of a randomized controlled trial comparing the accuracy of component positions, early functional outcomes, patient-reported outcome measures, and complications in conventional jig-based unicompartmental knee arthroplasty with navigational control (CO UKA) with robotic arm-assisted unicompartmental knee arthroplasty (RO UKA) for patients who have medial compartment knee osteoarthritis (OA).
METHODS
In total, 107 patients with symptomatic medial compartment OA were prospectively randomized to undergo CO UKA (n = 52) or RO UKA (n = 55), representing the currently available recruited cohort. Patients in both treatment groups had CT-based surgical planning. All procedures were completed using the medial parapatellar approach, and all patients received a standardized postoperative rehabilitation programme. Predefined study outcomes were recorded at regular intervals for two years after surgery.
RESULTS
RO UKA was associated with increased accuracy in executing the planned femoral (p < 0.001) and tibial (p < 0.001) component positions compared with CO UKA. RO UKA was associated with reduced inpatient pain scores (p < 0.001), decreased inpatient opioid analgesia consumption (p = 0.008), and shorter length of hospital stay (p = 0.004) compared with CO UKA. There were no differences between the treatment groups in the Oxford Knee Score (p = 0.299), Knee Injury and Osteoarthritis Outcome Score (p = 0.261), and Western Ontario and McMaster Universities Arthritis Index (p = 0.281) at two-year follow-up. RO UKA was associated with improved Forgotten Joint Score (FJS) at six-month (p = 0.002) and two-year (p = 0.021) follow-up. Patient recruitment declined during the trial as an increasing proportion of eligible patients expressed a preference for RO UKA, and operating surgeons experienced reduced clinical equipoise between the treatment groups.
CONCLUSION
The interim results of this study show that RO UKA was associated with increased accuracy in achieving the planned femoral and tibial component positions, improved early functional recovery, and decreased length of hospital stay compared with CO UKA. RO UKA was associated with higher FJSs compared with CO UKA at short- to mid-term follow-up.