No clinical and functional benefit after medial congruent compared to ultra congruent total knee arthroplasty at 1...

Various conforming bearing designs are used during total knee arthroplasty (TKA), yet their impact on clinical outcomes remains uncertain. In recent years, the use of medial congruent (MC) and ultra congruent (UC) onlays has gained popularity. Hence, this study aims to evaluate the clinical outcomes of MC onlays compared to UC onlays in TKA.

A prospective randomized controlled trial including 80 patients with advanced varus knee osteoarthritis undergoing primary TKA was conducted. Patients were randomly assigned to receive either a MC (n = 40) or UC insert (n = 40). Seventy-six patients (MC = 38; UC = 38) completed the 12-month follow-up. The primary outcome was the Knee Society Score (KSS), assessed preoperatively, at 6 weeks and 12 months postoperatively. Secondary outcomes included range of motion (ROM) and patient-reported outcome measures (PROMs): Oxford Knee Score (OKS), Forgotten Joint Score (FJS-12) and High-Activity Arthroplasty Score (HAAS) at 3, 6 and 12 months. Patient satisfaction, recommendation and willingness to undergo the procedure again were evaluated at 12 months. Radiographic alignment was assessed pre- and postoperatively.

Both groups showed significant improvement in the primary outcome KSS (MC: 87.6 ± 24.9 to 172.2 ± 20.3; UC: 94.2 ± 20.6 to 174.0 ± 23.7; p < 0.001 within both groups), ROM and PROMs without significant intergroup differences at any time point (all p > 0.05). The overall satisfaction rate (very satisfied + satisfied) was 94.7% in the MC group and 92.1% in the UC group with no significant difference in the distribution of satisfaction responses between groups (p = 0.994).

Both MC and UC inserts provided excellent clinical and functional outcomes 1 year after TKA, with high patient satisfaction and no statistically significant differences between designs. Thus, MC or UC designs may be chosen according to surgeon preference.

Level I.