Early Outcomes of Cruciate-Retaining Versus Posterior-Stabilized Total Knee Arthroplasty in Younger Patients: A Prospective Eastern European Cohort Study.

Background/Objectives: Cruciate-retaining (CR) and posterior-stabilized (PS) total knee arthroplasty (TKA) are both widely used in primary knee osteoarthritis (KOA), but evidence in younger patients remains limited. This study compared functional outcomes, pain, range of motion, quality of life, and psychological status between CR and PS implants in an Eastern European cohort. Methods: A prospective comparative cohort study was conducted in patients aged 40-64 years undergoing primary cemented TKA. The primary outcome was change in the Lower-Extremity Functional Scale (LEFS) at 12 months. Secondary outcomes included the Lysholm Knee Scoring Scale, EQ5D5L index, visual analogue scale (VAS) for pain, PROMIS Depression score, active knee flexion, and patient satisfaction. Outcomes were evaluated at baseline, 6 weeks, 3 months, 6 months, and 12 months. Between-group comparisons used Welch t-tests and results are reported as mean differences with 95% confidence intervals. Results: A total of 147 patients were included (CR n = 71; PS n = 76). The prespecified primary endpoint, 12-month change in LEFS, was very similar between groups (mean difference 0.14 points, 95% CI -3.80 to 4.08; p = 0.94). LEFS improved from 49.1 ± 14.8 to 66.8 ± 11.6 in the CR group and from 47.9 ± 14.6 to 65.8 ± 12.4 in the PS group at 12 months. Lysholm scores increased to 88.5 ± 11.4 (CR) and 86.2 ± 10.6 (PS) (p = 0.21). EQ-5D-5L improved in both groups, with a non-significant difference at 12 months (p = 0.077). VAS pain decreased from 7.39 ± 1.19 to 1.59 ± 0.84 (CR) and from 7.55 ± 1.46 to 1.75 ± 0.90 (PS) (p = 0.27). Active flexion increased to 117.5 ± 10.5° (CR) and 115.0 ± 11.3° (PS) (p = 0.15). PROMIS Depression improved similarly in both groups, and satisfaction levels at 12 months were comparable. Conclusions: Both CR and PS TKA produced comparable improvements in pain, function, quality of life, mental health, and knee flexion in KOA patients aged 40-64 at one year. Implant design did not influence clinical benefit or PROMs in this cohort.