Excellent midterm functional and clinical outcomes of bi-cruciate retaining versus cruciate retaining total knee arthroplasty: A prospective cohort study

Purpose: bi-cruciate retaining total knee arthroplasty (BCR-TKA) is recognised as an alternative to a Cruciate Retaining Total Knee Arthroplasty (CR-TKA) in the pursuit of reducing joint awareness and approaching a ‘forgotten artificial knee joint’. The aim of this retrospective cohort study was to provide a short-term comparison on functional and clinical outcomes between BCR-TKA and CR-TKA in osteoarthritis patients. Methods: The cohort consisted of 61 BCR-TKA patients, matched for age, BMI and sex with 61 CR-TKA patients. They were operated on between 2014 and 2016. Patient-Reported Outcome Measurements, including the Forgotten Joint Score (FJS-12), Oxford Knee Score (OKS), Western Ontario and McMaster Osteoarthritis (WOMAC) and Visual Analogue Score (VAS) pain, were collected preoperatively and at 3-, 12-, 24-months and 5-years postoperatively. Additionally, domain-specific questionnaires were included, such as the FJS. Effect size for the FJS-12 was calculated at the 3-year follow-up to quantify the difference between BCR- and CR-TKA. Functional performance was additionally evaluated using a validated balance-based exergaming system, consisting of a pressure-sensitive balance platform delivering real-time visual feedback to quantify dynamic stability. Results: At 5-year follow-up, BCR-TKA showed significantly better patient-reported outcome measures (PROMs) than CR-TKA, including joint awareness, stiffness, function, pain and daily activity-related disabilities (FJS-12, OKS, WOMAC, VAS pain). In the subgroup completing exergaming assessment, BCR-TKA demonstrated superior dynamic stability (71.91% vs. 66.90%, p = 0.021). The 5-year survival rate was 98.4% for BCR-TKA and 95.1% for CR-TKA, with no significant difference in revision rates. Conclusion: BCR-TKA resulted in superior midterm joint awareness and functional outcomes compared to the CR-TKA. Additionally, objective data collected through exergaming demonstrated a positive trend in favour of BCR-TKA, further supporting its functional benefits. This study illustrates that the bi-cruciate retaining surgical technique for TKA is a promising step toward reducing joint awareness and achieving the ‘forgotten’ artificial knee. As ACL preservation may enhance rotational stability and proprioception, future research should incorporate high-resolution kinematic analyses such as 3D gait analysis. Level of Evidence: Level III therapeutic, retrospective cohort study.